Session Index

S7. Display and Solid State Lighting

Display and Solid State Lighting I
Friday, Dec. 1, 2023  13:00-15:00
Presider: Prof. Shie-Chang Jeng (National Yang Ming Chiao Tung University, Taiwan) Prof. Jian-Jang Huang (National Taiwan University, Taiwan)
Room: 92277 (2F)
13:00 - 13:30
Manuscript ID.  0651
Paper No.  2023-FRI-S0701-I001
Invited Speaker:
Tsung-Hsien Lin
Technological Development of Liquid Crystal Smart Window
Tsung-Hsien Lin, National Sun Yat-Sen University (Taiwan)

Smart window is the films/glasses having the incredible feature of controlling heat, privacy, and getting their transmission properties changed from opaque to translucent to transparent under the influence of voltage. The flow of light and heat between indoor and outdoor is controllable, providing human life more convenient and comfortable. This market is expected to witness notable growth in the coming years due to the increasing demand of smart film/glass based products in various industrial sectors, such as automotive and construction. Smart window technique such as Polymer dispersed liquid crystal (PDLC), Electrochromic glass (EC) and Suspended particles devices (SPD) accounted for 90% of the market. However, these techniques can be only operated at a single function. In order to achieve true energy conservation and versatility, it is highly desirable but challenging to design a single device capable of simultaneously modifying haze and tint as well as exhibiting multi-stability. In this presentation, I will talk about the recent technology and development of multi-functional LC smart windows.

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13:30 - 13:45 Award Candidate (Paper Competition)
Manuscript ID.  0183
Paper No.  2023-FRI-S0701-O001
Guan-Fu Sung A misrecognized heating effect originating seemingly from dielectric relaxation in a dual-frequency liquid crystal cell
Guan-Fu Sung, College of Photonics (Taiwan); Wei Lee, Institute of Imaging and Biomedical Photonics (Taiwan)

Our previous research has attracted considerable attention due to our newfound understanding of the pseudo-dielectric relaxation-induced heating effect, known as pseudo-dielectric heating (PDH). It has often been mistakenly considered as dielectric heating (DH) caused by orientational relaxation in liquid crystal (LC). However, the (co)existence of both PDH and DH effects in dual-frequency (DF) LC cells remains unclear. In this study, we unveil a completely new and never-before-seen heating behavior in a DFLC cell, ultimately providing evidence for the independent existence of DH and PDH behaviors in a DFLC cell.

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13:45 - 14:00 Award Candidate (Paper Competition)
Manuscript ID.  0171
Paper No.  2023-FRI-S0701-O002
Yu-Hua Chou Microfluidic laser based on polymeric chiral nematic liquid crystal cavity
Yu-Hua Chou, Jia-De Lin, National Dong Hwa University (Taiwan)

This work demonstrates the first miniature dye laser integrating a microfluidic gain medium and a self-organized laser cavity composed of a chiral nematic liquid crystal polymer template. The emission features of the microfluidic laser and the static laser are compared. By
continuously infiltrating fluidic gain medium into the chiral nematic polymer template, the lasting time for the lasing emission can be significantly prolonged compared to the static one. The prototype proposed in this work moves liquid crystal lasers further toward practical applications.

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14:00 - 14:15 Award Candidate (Paper Competition)
Manuscript ID.  0771
Paper No.  2023-FRI-S0701-O003
Zhi-Qun Wang Electro-regulatable reflective optical vortex generator based on polymer stabilized cholesteric liquid crystals
Zhi-Qun Wang, You-Jyun Chen, Chia-Rong Lee, National Cheng Kung University (Taiwan)

This experiment combines polymer-stabilized cholesteric liquid crystals (PSCLCs) reflection band broadening and planar phase modulation techniques, allowing cholesteric liquid crystals, typically characterized by narrow reflection bands, to achieve full visible light operation under applied electric fields. Taking the vortex beam element as an example and verified through Michelson interferometry, the fabricated device simultaneously reflects red, green, and blue vortex beams under low voltage (≤16 V) modulation, confirming the feasibility of applying PSCLC technology in planar phase elements.

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14:15 - 14:30 Award Candidate (Paper Competition)
Manuscript ID.  0788
Paper No.  2023-FRI-S0701-O004
Yuan-Chao Wang Improving Output Power Efficiency of InGaN/GaN Green Micro-LEDs through Selective Sidewall Ion Implantation
Yuan-Chao Wang, Yu-Hsiang Chang, Jian-Jang Huang, NTU (Taiwan)

In this work, we propose an ion implantation method to deliberately create high-resistivity sidewall in the InGaN/GaN green LED. Our study demonstrates that ion implantation improves electrical properties, manifested by increased forward current and decreased reverse leakage, mainly due to the effective suppression of sidewall defects.

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14:30 - 14:45 Award Candidate (Paper Competition)
Manuscript ID.  0757
Paper No.  2023-FRI-S0701-O005
Huai-Chin Huang The effects of V-defect semipolar sidewall plane on the red InGaN MQW LEDs with random alloy fluctuation effects
Huai-Chin Huang, Shih-min Chen, Yuh-Renn Wu, National Taiwan University (Taiwan)

Strong piezoelectric field-induced barriers hinder vertical QW injection in red nitride-based light-emitting diodes (LEDs). The V-defects can decrease the forward voltage (Vfor) with the semipolar InGaN QW at the inclined surface. Simulations demonstrate that the primary light-emitting QW layer will shift whenever the QW number rises to 10 due to the carrier injection, whether or not the V-defect is considered. Also, the indium composition on the sidewall affects carrier injection and balance. This study will analyze the impact of the QW number, the structure of the V-defect, and the indium composition of the inclined sidewall QW.

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14:45 - 15:00 Award Candidate (Paper Competition)
Manuscript ID.  0986
Paper No.  2023-FRI-S0701-O006
Ting-Jhih Kuo An investigation on an over-3000-PPI color conversion layer with colloidal quantum dots
Ting-Jhih Kuo, Han-Yu Chao, Chien-Chung Lin, National Taiwan University (Taiwan)

In this study, we demonstrate the QD patterning, which can be considered as a micro-sized color
conversion layer. Our QD patterning size is 2um, and it is achieved via dropping QD solution and
semiconductor processes.

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S7. Display and Solid State Lighting

Poster Session I
Friday, Dec. 1, 2023  13:30-16:30
Room: Building of Electrical Engineering (電機系館) (B1)
Award Candidate (Paper Competition)
Manuscript ID.  0822
Paper No.  2023-FRI-P0701-P001
Zheng-Wei Lu Passive liquid crystal smart window featuring selectable thermally normal- and reverse-mode operations
Zheng-Wei Lu, Institute of Photonic System (Taiwan); Wei Lee, Institute of Imaging and Biomedical Photonics (Taiwan)

We successfully developed a mode-selectable and temperature-controlled guest–host smart window. This achievement was realized by adjusting the concentration of a thermoresponsive chiral dopant along with a typical left-handed chiral dopant to optimally manipulate the gap-to-pitch ratio. Additionally, we harnessed the properties of a dual-frequency liquid crystal as the host. This innovative window offers both switchable normal- and reverse-modes, each capable of modifying the switching temperature by applying a low voltage with varying frequencies. Moreover, both modes can actively adjust transmittance at will. This design provides an expanded range of control options and holds significant potential for practical applications.

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Award Candidate (Paper Competition)
Manuscript ID.  0045
Paper No.  2023-FRI-P0701-P002
Yu-Chieh Chang Polymer-separated double-layer structure of cholesteric liquid crystals for wide bandwidths
Yu-Chieh Chang, Chun-Chuan Wang, Kuan-Wu Lin, Chun-Ta Wang, National Sun Yat-Sen University (Taiwan)

By exposing polymer-cholesteric liquid crystal (CLC) composites to ultraviolet
(UV) light, a polymer-separated double-layer structure can be formed due to the uneven
polymerized reactions of polymers in the top and bottom regions, respectively. This doublelayer cholesteric structure exhibits two reflection bands, allowing the reflection bandwidth in
CLCs to be broadened. The broadened bandwidth allows light to be manipulated in novel
ways, enabling the development of advanced optical devices with improved performance.

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Award Candidate (Paper Competition)
Manuscript ID.  0831
Paper No.  2023-FRI-P0701-P003
Chih-Hui Huang Electrochromic liquid crystals doped with dichroic dyes for multi-color displays
Chih-Hui Huang, Sin-Wei Lin, Cheng-Kai Liu, Ko-Ting Cheng, National Central University (Taiwan)

This report proposes a device possessing both electrochromism and dichroism, and both properties can be individually controlled by direct current (DC) and alternating current (AC) electric fields. A color-mixing result can be also obtained by applying DC and AC electric fields at the same time.

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Award Candidate (Paper Competition)
Manuscript ID.  0212
Paper No.  2023-FRI-P0701-P004
Cheng-Ying Wu Patterned nematic liquid crystals by two-photon polymerization
Cheng-Ying Wu, Jia-De Lin, National Dong Hwa University (Taiwan)

This work demonstrates two-photon polymerization direct laser writing (2PP-DLW) in polymer-stabilized nematic liquid crystals. The writing parameters, including laser power, writing velocity, writing repetition, and writing route, are discussed. According to the writing parameters, the patterned polymer-stabilized nematic liquid crystals can be transparent or opaque, which can result in the polarization modulation of light and scattering, respectively. With the electric-optical response of liquid crystals, electrically controllable phase or amplitude diffraction elements can be fabricated by this technique and applied to hidden optics or planar optics.

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Award Candidate (Paper Competition)
Manuscript ID.  0296
Paper No.  2023-FRI-P0701-P005
Guan-Yu Su Using localized surface plasmon resonance for realizing near-infrared OLEDs
Guan-Yu Su, Pin-Yin Huang, Ming-Jun Lin, Chia-Chen Chung, Jian-Sheng Hong, Chih-Hao Chang, Yuan Ze University (Taiwan)

This study proposes a unique electrode structure design for accelerated development
of near-infrared (NIR) OLEDs. Silver nanoparticles coated with titanium dioxide, followed by
ITO deposition, create a transparent electrode with localized surface plasmon resonance. Red
phosphorescent OLEDs on these electrodes utilize an exciplex system to optimize efficiency
and reduce operating voltages. The dopant used in OLEDs is an efficient deep-red
phosphorescent material, Ir(fliq)₂acac, with a wavelength of 650 nm. The results demonstrate
that this unique electrode design transforms deep-red light-emitting devices into near-infrared
devices with adequate efficiency. This design overcomes NIR material development limitations,
opening new directions for future advancements.

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Award Candidate (Paper Competition)
Manuscript ID.  0292
Paper No.  2023-FRI-P0701-P006
Yi-Ting Chen Advancing efficient red phosphorescent OLEDs using donor-acceptor-donor hosts
Yi-Ting Chen, Yi-Qi Chao, Chih-Hao Chang, Yuan Ze University (Taiwan); Tsz-Chung Yiu, Gnanasekaran Premkumar, Yun-Zi Zeng, Yu-Ting Lin, Yuan Jay Chang, Tunghai University (Taiwan)

Six donor-acceptor-donor (D-A-D) materials were designed and synthesized as efficient hosts for red phosphorescent OLEDs. These compounds, using three types of acceptors (TXO, DBTS, and SpDBTS) with phenyl-carbazole (CzP or PCz) donors, demonstrated triplet energy gaps higher than the emitter (Ir(piq)₂acac), ensuring effective energy transfer. Blending the synthesized compounds with CN-T2T improved carrier balance. Among them, the DBTS-CzT/CN-T2T mixed host showed excellent EL characteristics with a high efficiency of 21.7% (13.4 cd/A) and a low turn-on voltage of 2.2 V. These results highlight their potential for use in efficient red phosphorescent OLEDs.

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Award Candidate (Paper Competition)
Manuscript ID.  1017
Paper No.  2023-FRI-P0701-P007
Chun-Yu Chen Regulation of Singlet Fission Dominated by Tetracene-based Organic Light-emitting Diodes.
Chun-Yu Chen, Tzu-Yu Huang, Yulin Lin, Anas Mujahid, Tzung-Fang Guo, National Cheng Kung University (Taiwan)

Using magnetic field effects analysis, we report a significant change between tetracene-only and tetracene/C60 devices, after we deposit the C60 on the tetracene active layer, we got a huge different line shape in magneto-photocurrent (MPC) and photoluminescence (PL) which indicates that the tetracene/C60 device will form CT-complex (Charge Transfer complex). In addition, we further confirm this result from magneto-current (MC) and magneto-electroluminescence (MEL), We can verify that with and without C60 have a big effect on tetracene-based devices, and the main reason is the formation of the CT-complex.

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Award Candidate (Paper Competition)
Manuscript ID.  0085
Paper No.  2023-FRI-P0701-P008
Hsin-Yuan Huang Exciplex-forming Cohost Systems for High Efficiency Red OLEDs
Hsin-Yuan Huang, National Taiwan Ocean University (Taiwan); Yi-Sheng Chen, Ming Chi University of Technology (Taiwan); Ken-Tsung Wong, National Taiwan University (Taiwan); Wen-Yi Hung, National Taiwan Ocean University (Taiwan)

Two 2,7-dicyaonfluorene-based molecules are utilized as acceptors (A) to combine with hexaphenylbenzene-centered donors (D) for probing the exciplex formation. To further utilize the exciton electrically generated in exciplex-forming system, the D-A-D-configurated fluorescence emitter DTPNT is doped into the DDP-HPB:27-tDCN blend. The nice spectral overlap ensures fast and efficient Förster energy transfer (FRET) process between the exciplex-forming host and the fluorescent quests. The red device adopting DDP-HPB:27-tDCN:5 wt% DTPNT as the EML gives EL λmax of 655 nm and EQE of 6.1%.

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Award Candidate (Paper Competition)
Manuscript ID.  0291
Paper No.  2023-FRI-P0701-P009
Ya-Hsin Cheng Carbazole-based molecules with star shapes for realizing efficient OLEDs
Ya-Hsin Cheng, Jia-Fan Wu, Chih-Hao Chang, Yuan Ze University (Taiwan); Yuan-Jay Chang, Tunghai University (Taiwan)

We designed three kinds of hole-transporting materials that use a phenyl or a pyrimidine to connect two 3,6-bis(trifluoromethyl)-9-methyl-9H-carbazole moieties with a different substitution. These compounds have an adequate energy bandgap suitable as host materials for green emitters. These materials are combined with B3PyMPM in a 3:7 ratio to construct a mixed host in the devices. As a result, the CFCz2/B3PyMPM-based OLEDs with Ir(ppy)₃ green emitter has the best performance, achieving a peak efficiency of 19.8% (68.4 cd/A, 85.0 lm/W), a low turn-on voltage of 2.4 V, and high maximum luminance of 91141 cd/m².

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Award Candidate (Paper Competition)
Manuscript ID.  0293
Paper No.  2023-FRI-P0701-P010
Jia-Fan Wu Efficient green phosphorescent OLEDs using bicarbazolebased hole-transporting materials
Jia-Fan Wu, Ya-Hsin Cheng, Chih-Hao Chang, Yuan Ze University (Taiwan); Yuan-Jay Chang, Tunghai University (Taiwan)

We designed a series of bicarbazole-based hole-transporting materials where two
carbazole moieties were connected at different positions to synthesize four compounds. These compounds have an adequate energy bandgap suitable as host materials for green emitters. These materials are combined with B3PyMPM to construct a mixed host in the devices. As a result, the H4/B3PyMPM-based OLED with Ir(ppy)₃ green emitter has superior performance, achieving a peak efficiency of 24.1% (84.5 cd/A, 110.6 lm/W), a low turn-on voltage of 2.2 V, and high maximum luminance of 87113 cd/m². These results demonstrate the effectiveness of our molecular designs and the device architectures.

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Award Candidate (Paper Competition)
Manuscript ID.  0707
Paper No.  2023-FRI-P0701-P011
Wei-Yun Hung Exciplex-forming Cohost Systems with Carbozole-based Donors for High Efficiency Sky-blue OLEDs
Wei-Yun Hung, National Taiwan University of Science and Technology (Taiwan); Dian Luo, Yi-Sheng Chen, Ming Chi University of Technology (Taiwan); Chih-Chien Lee*, National Taiwan University of Science and Technology (Taiwan); Shun-Wei Liu*, Ming Chi University of Technology (Taiwan)

Through the strategic optimization of the donor-to-acceptor ratio within the emissive layer (EML), effective conduction within the exciplex-based OLED is achieved. This optimization culminates in a notable enhancement of the external quantum efficiency of the exciplex-based OLED, elevating in to 8.51%.

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Award Candidate (Paper Competition)
Manuscript ID.  0760
Paper No.  2023-FRI-P0701-P012
Wei-Zhi Chen Simulations of the performance of different hyper triplet-triplet fusion OLEDs with carriers and exciton
Wei-Zhi Chen, Hsiao-Chun Hung, Chia-Hsun Chen, Hung-Yi Lin, Yuan-Zhen Zhuang, Jiun-Haw Lee, Tien-Lung Chiu, Yuh-Renn Wu, National Taiwan University (Taiwan)

In this work, the exciton diffusion model coupled with a drift-diffusion solver is used to simulate the hyper-TTF-OLEDs devices. We analyze the efficiency and loss mechanisms to demonstrate that the main reason for internal quantum efficiency (IQE) loss is the triplet-polaron quenching (TPQ) and the ability of triplet exciton diffusion. In device with PPC EML, the TPQ is the weakest, and triplet diffusion is the best. Hence, triplet excitons efficiently transfer to the NPAN layer and improve the triplet-triplet fusion (TTF) and IQE. The above results also confirm the excellent IQE in device C, which reaches up to 34.1%.

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Award Candidate (Paper Competition)
Manuscript ID.  1010
Paper No.  2023-FRI-P0701-P013
Sung-Jung Lin Quantum-Dot Vertical Light-Emitting Transistors based on Integration of ZnO transistor and Quantum-Dot Light-Emitting Diode
Sung-Jung Lin, Wei-Jie Liao, Ying-You Lin, Jia-Min Yu, Jui-Fen Chang, National Central University (Taiwan)

We develop quantum-dot (QD) vertical light-emitting transistors (QVLETs) by integrating ZnO transistors and QLEDs based on the encapsulated source electrode transistor geometry, and modify the nanocrystalline ZnO and polyethyleneimine (PEI) blend film as the electron injection layer (EIL) for device optimization. By blending an appropriate PEI ratio in the EIL, we achieve the optimal device with the highest external quantum efficiency of ~3% and uniform emission in the ZnO transistor channel area. This QVLET design features high performance and a controlled emission area, making it suitable for developing high-resolution display applications.

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Award Candidate (Paper Competition)
Manuscript ID.  0298
Paper No.  2023-FRI-P0701-P014
Fu-Chuan Fan A specific charge generation layer for realizing highly efficient red tandem OLEDs
Fu-Chuan Fan, Chih-Hung Ko, Yu-Chieh Chang, Cheng-Yung Ho, Chih-Hao Chang, Yuan Ze University (Taiwan)

This study focuses on the charge generation layer (CGL) structure to design more efficient tandem OLEDs with higher efficiency and brightness. We proposed a specific design of a CGL structure, which inserted a thin layer of Li₂CO₃ between the double organic heterojunction (OHJ) pair. The current density of the proposed CGL device exceeded the control CGL device. Furthermore, the tandem device with the proposed CGL exhibited much higher EL performance than the conventional CGL with double OHJ pairs. This result demonstrates that our proposed CGL design effectively simplifies the device architecture and improves efficiency.

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Award Candidate (Paper Competition)
Manuscript ID.  0295
Paper No.  2023-FRI-P0701-P015
Zih-Ru He Green thermally activated delayed fluorescence OLEDs using a carbene−Cu(I)−amide complex
Zih-Ru He, Chi-Hao Huang, Shih-Wei Huang, Kuan-Wei Chen, Chih-Hao Chang, Yuan Ze University (Taiwan); Kaspars Traskovskis, Riga Technical University (Latvia)

Luminescent carbene-metal-amide complexes bearing group 11 metals have drawn
significant attention due to exceptional emission and high radiative decay rates. Herein, a
newly developed Cu(I) complex bearing carbenes has been investigated and analyzed
concerning their light emission properties and OLED application. After finetuning the device
architecture, four different doping concentrations were adopted to maximize the EL
performance. The results revealed that the green TADF device with a doping concentration of
15 weight percent demonstrated the highest efficiency of 8.6% (26.3 cd/A), indicating the
potential of the synthesized complex for TADF emission.

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Award Candidate (Paper Competition)
Manuscript ID.  0488
Paper No.  2023-FRI-P0701-P016
Chen-huang Chiu Blue triplet-triplet annihilation organic light-emitting diode based on boron-containing anthracene derivative and bilayer structure
Chen-huang Chiu, Nation Taiwan University (Taiwan); Chia-Hsun Chen, Nation Taiwan University (Taiwan), National Taiwan Unversuty (Taiwan); Bo-Yen Lin, National Dong Hwa University (Taiwan); Man-kit Leung, National Taiwan Unversuty (Taiwan); Jiun-haw Lee, Nation Taiwan University (Taiwan); Tien-Lung Chiu, Yuan Ze University (Taiwan)

Blue organic light-emitting diode based on triplet-triplet annihilation (TTA) was demonstrated with boron-containing anthracene as the host of the emitting layer, together with bilayer structure, which achieved a current efficiency of 13.65 cd/A, a power efficiency of 11.96 lm/W, and an external quantum efficiency of 10.35%.

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Manuscript ID.  0670
Paper No.  2023-FRI-P0701-P017
Chen-Han Lu Efficient Deep-Blue OLEDs Based on Thermally Activated Delayed Fluorescence Emitters with Macrocyclic Donors
Chen-Han Lu, Chun-Yen Lin, Chia-Hsun Chen, Jiun-Haw Lee, Ken-Tsung Wong, Chung-Chih Wu, National Taiwan University (Taiwan)

In this work, a series of deep-blue thermally activated delayed fluorescence (TADF) emitters were developed based on macrocyclic donors. Thorough investigations on photophysical properties of the emitters were carried out to establish the structure-property relationship and verify the progressive hypsochromic shifts. Also, in the presence of macrocyclic donors, these new emitters show high horizontal dipole ratios. The efficient TADF character, high photoluminescence quantum yields, and high anisotropic emission dipole ratios work together to render the superior electroluminescence (EL) efficiencies, together with satisfactory deep-blue emissions.

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Manuscript ID.  0127
Paper No.  2023-FRI-P0701-P018
Chen-Hsun Wu Nanoparticles doped into Transparent Photoresist Enhance the Efficiency of the Color Conversion Layer for Micro-LED Displays Technology
Chen-Hsun Wu, Chi-Shiang Chen, Chih-Yuan Tsai, Shan-Yu Chen, Ching-Fuh Lin, National Taiwan University (Taiwan)

Micro-light emitting diodes (Micro-LEDs) displays with remarkable advantages are becoming mainstream in next-generation displays technology. However, further development of Micro-LEDs still encounters significant challenges, including mass transfer yield. In this study, we employed the color conversion layer (CCL) technology and doped the nanoparticles (NPs) into the transparent photoresist. The quantum yield (QY) variations of ZnO and SiO2 NPs are investigated. We achieve up to 70.6% QY and absorbance 93.0% in dual path measurements. This lays the foundation for achieving high-performance Micro-LEDs displays for AR/VR applications achieved pixel miniaturization in the future.

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Manuscript ID.  0004
Paper No.  2023-FRI-P0701-P019
Min-Chih Hou Light-Emitting Electrochemical Cells Based on Au(III) Complexes
Min-Chih Hou, National Yang Ming Chiao Tung University (Taiwan); Valerio Giuso, Matteo Mauro, Université de Strasbourg & CNRS (France); Hai-Ching Su, National Yang Ming Chiao Tung University (Taiwan)

A series of cationic complexes of general formula [(C^C)Au(P^P)]X, where C^C = 4,4'-di-tert-butyl-1,1'-biphenyl, P^P is a diphosphine ligand and X is a non-coordinating counter-anion, are employed as the electroactive materials of the first proof-of-concept light-emitting electrochemical cell (LEC) devices. These complexes show emission maxima in the green-yellow region with moderate to high photoluminescence quantum yields. The LECs achieve peak external quantum efficiency, current efficiency, and power efficiency up to ca. 1%, 2.6 cd A-1, and 1.1 lm W-1, respectively, showing the potential use of these novel emitters as emissive compounds in LEC devices.

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Manuscript ID.  0460
Paper No.  2023-FRI-P0701-P020
Lian-Chun Huang Pyrene-carbazole derivative as host of emitting layer for bilayer blue organic light-emitting diode
Lian-Chun Huang, Jiun-Haw Lee, Chia-Hsun Chen, National Taiwan University (Taiwan); Bo-Yen Lin, Donghua University (Taiwan); Yi-Ru Huang, Man-Kit Leung, National Taiwan University (Taiwan); Tien-Lung Chiu, Yuan Ze University (Taiwan)

In this study, pyrene-carbazole (PC) derivative was used as one host material for blue fluorescence organic light-emitting diode (OLEDs) exhibiting bilayer emitting layer (BEML) structure, which consisted of PC and anthracene as the hosts, respectively. By optimizing the dopant concentration of PC-EML, maximum current efficiency (C.E.max) of 15.40 cd/A, maximum power efficiency (P.E.max) of 10.92 lm/W, maximum external quantum efficiency (EQEmax) of 11.13% and CIE coordinates of (0.139 0.210) were achieved in this blue OLED.

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Manuscript ID.  0591
Paper No.  2023-FRI-P0701-P021
Zheng-Yu Wei Anthracene based host material for blue OLED
Zheng-Yu Wei, Chia-Hsun Chen, Jiun-Haw Lee, National Taiwan University (Taiwan); Bučinskas Audrius, Dmytro Volyniuk, Gražulevičius Juozas Vidas, Kaunas University of Technology (Lithuania); Pavel Arsenyan, Aizkraukles 21 (Lithuania); Tien-Lung Chiu, Department of Electrical Engineering (Taiwan)

In this research, a novel host material with anthracene moiety was used for blue organic light-emitting diodes (OLEDs). By incorporating dopants into the emissive layer (EML), the device achieved a maximum current efficiency (CEmax) of 8.31 cd/A, a maximum power efficiency (PEmax) of 7.45 lm/W, Commission Internationale de l'Eclairage (CIE) coordinates of (0.144, 0.196), and a peak emission wavelength at 462 nm. And the maximum external quantum efficiency (EQEmax) reached 5.43%.

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Manuscript ID.  0014
Paper No.  2023-FRI-P0701-P022
Chih-Yuan Tsai Nanoparticle-enhanced Color Conversion Pixel Array for Micro-LED Displays
Yen-Chia Cheng, Chien-Hung Lin, Chih-Yuan Tsai, Chi-Shian Chen, Ching-Fuh Lin, National Taiwan University (Taiwan)

Micro light-emitting diode (Micro-LED) are gradually becoming the mainstream technology for high-end displays. This research achieves a full-color Micro-LED display by combining a color conversion layer (CCL) with a blue-light Micro-LED array. To enhance the color conversion layer and reduce pixel size, nanoparticles are utilized in the CCL, and a process is designed to address nanoparticle accumulation in the pixel array. In the fabrication of a 4×4 μm pixel array, the pixel density reaches 5080 PPI for single-color and 2540 PPI for full-color displays. By achieving a nanoparticle-enhanced full-color Micro-LED display, our results offer further possibilities for display technology.

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Manuscript ID.  0914
Paper No.  2023-FRI-P0701-P023
Zhi-An Lin Optimization of Graded EBL and Short Period Superlattice in DUV LEDs of Various QW Structures
Yi-Man Lin, Man-Fang Huang, Lin Lin, Jih-Yuan Chang, Yen-Kuang Kuo, Zhi-An Lin, National Changhua University of Education (Taiwan)

The performance of deep ultra-violet light-emitting diode may be improved by implementing graded layers for both electron-blocking layer and short period superlattice. Reduction in operation voltage is obtained, which is attributed to the reduction in polarization effect. Moreover, in order to reduce the influence of relatively large Auger nonradiative recombination rate in deep ultra-violet spectral range, the number of quantum wells is further increased to eight to reduce the carrier concentration in each individual quantum well. The overall nonradiative recombination rate in the active region is decreased and hence the performance of deep ultra-violet light-emitting diode is further improved.

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Manuscript ID.  0092
Paper No.  2023-FRI-P0701-P024
Min-Han Lu A thermally reverse-mode liquid crystal as an advancing smart window in active and passive operations
Guan-Fu Sung, College of Photonics (Taiwan); Min-Han Lu, Institute of Lighting and Energy Photonics (Taiwan); Wei Lee, Institute of Imaging and Biomedical Photonics (Taiwan)

We present an innovative smart window that employs dye-doped dual-frequency liquid crystal (LC) to enable electrically and thermally controlled reverse-mode operation. The devised window automatically adjusts its transparency in response to temperature, ransitioning between two optical states corresponding to two distinct levels of transmission. This smart window benefits from the unique properties of dielectric anisotropy tunability, permitting it to switch between distinct optical states including dynamic scattering at specific electric-field frequencies. We conducted an in-depth study of the temperature-dependent dielectric anisotropy of the material. Our research provides a new pathway toward applications in sensor-based optical devices.

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Manuscript ID.  1024
Paper No.  2023-FRI-P0701-P025
Jing-Xuan Wei Electro-optical bistability of polymer stabilized cholesteric liquid crystals
Wen-Chieh Chang, Tien-Jung Chen, Jing-Xuan Wei, Nation Taipei University of Technology (Taiwan)

Nematic liquid crystals (NLCs) composed of rod-shape molecules and bent-shape molecules, were added with chiral dopant to form cholesteric liquid crystals (CLCs). A mixture was formed by doping a small amount of monomers to cholesteric liquid crystals. The ULH (uniform lying helix) structure was obtained through a cooling-induced phase transition. A UV light was used to polymerize the monomer to stabilize the ULH structure. Applying a pulsed electric field to unwind the helical axis results in a mixed state, which applied with a pulsed electric field at a lower voltage, can be switched back to the ULH state.

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Manuscript ID.  0730
Paper No.  2023-FRI-P0701-P026
Zong-Ying He Qualitatively Evaluating Optical Aberrations of Liquid Crystal Lenses with Interferogram Analysis
Zong-Ying He, Guan-Chen Chen, Chia-Rong Sheu, National Cheng Kung University (Taiwan)

In this study, it is proposed that electrically driving liquid crystal lenses are investigated optical aberrations by means of interferogram analysis. Liquid crystal (LC) lenses possess a specific capability of electrically tunable focuses belonging to the type of GRIN (gradient refractive indexes) lenses, which propagating optical rays through the lens itself are curved trajectories rather than straight lines in the refractive lenses. In order to clearly analyze the imaging capabilities of electrically driving LC lenses, the interferogram analysis of Twyman-Green interferometer is used.

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Manuscript ID.  0875
Paper No.  2023-FRI-P0701-P027
Zi-Wen Su Pyrene-benzimidazole derivative as host of emitting layer in organic light-emitting diodes
Zi-Wen Su, Jiun-Haw Lee, Chia-Hsun Chen, National Taiwan University (Taiwan); Bo-Yen Lin, Donghua University (Taiwan); Man-Kit Leung, Chi-Chi Chang, National Taiwan University (Taiwan); Tien-Lung Chiu, Yuan Ze University (Taiwan)

In this research, a pyrene-benzimidazole derivative was synthesized and employed
as host of the emitting layer in blue fluorescence organic light-emitting diode (OLED), which achieved maximum external quantum efficiency (EQEmax) of 7.7% with the Commission Internationale de l'Eclairage (CIE) coordinates of (0.14, 0.23).

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S7. Display and Solid State Lighting

Display and Solid State Lighting II
Friday, Dec. 1, 2023  15:15-17:30
Presider: Prof. Tien-Lung Chiu (Yuan Ze University, Taiwan) Prof. Tzung-Fang Guo (National Cheng Kung University, Taiwan)
Room: 92277 (2F)
15:15 - 15:45
Manuscript ID.  0796
Paper No.  2023-FRI-S0702-I001
Invited Speaker:
Wai-yeung Wong
Recent Advances in Phosphorescent Metal Complexes
Wai-yeung Wong, The Hong Kong Polytechnic University (PolyU) (Hong Kong)

Organic light-emitting diodes (OLEDs) have received a great deal of interest owing to the huge market
application potentials as large-size, flexible, high-quality self-luminous display panels and lighting sources.
The performance of phosphorescent OLEDs is mainly limited by the phosphorescent transition metal
complexes (such as iridium(III), platinum(II)) and the hosts which can play a crucial role in furnishing
efficient energy transfer, balanced charge injection/transporting character and high quantum efficiency in
the devices. In this talk, the recent advances in the phosphorescent metal complexes functionalized with
various ligand moieties will be discussed from the point of view of their structure–property relationships.
Besides, near-infrared (NIR) light-emitting organic materials and their devices have aroused growing
interest recently due to their great potential for applications in photodynamic therapy, signal processing,
night-vision devices and information-secured displays. New and efficient strategies to develop NIR
phosphorescent emitters and soft salt complexes will also be presented and their optoelectronic applications
will be described.

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15:45 - 16:00 Award Candidate (Paper Competition)
Manuscript ID.  0725
Paper No.  2023-FRI-S0702-O001
Tzu-Yu Huang Modulating the Triplet-Triplet Annihilation to Singlet Fission Phenomena by Tuning the Thickness of Rubrene-Based Sub-bandgap Devices
Tzu-Yu Huang, Jun-Yu Cheng, Yulin Lin, Anas Mujahid, Tzung-Fang Guo, National Cheng Kung University (Taiwan)

Using magneto-electroluminescence (MEL), we report a significant change from triplet-triplet annihilation (TTA) to singlet fission (SF) in rubrene-based sub-bandgap devices through the modulation of rubrene thickness. We observe the dominant TTA when the rubrene layer is thinner, whereas; the thicker layer exhibits dominant SF during emission. In comparison to pristine rubrene devices, we find that the thickness of the rubrene layer in the sub-bandgap device effectively suppresses the TTA process.

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16:00 - 16:15 Award Candidate (Paper Competition)
Manuscript ID.  0268
Paper No.  2023-FRI-S0702-O002
Cheng-Rui Lu Emission Gate Driver Circuit with Adjustable Pulse for Use in AMOLED Displays
Cheng-Rui Lu, Cheng-Han Ke, National Cheng Kung University (Taiwan); Po-Cheng Lai, AUO Corporation (Taiwan); Chih-Lung Lin, National Cheng Kung University (Taiwan)

This work presents an emission (EM) gate driver circuit for AMOLED displays. The circuit decreases the gate voltage of the driving thin-film transistor (TFT) by capacitance coupling effect, enabling complete discharging. It also periodically stabilizes the output signal at a required low voltage (VGL). Furthermore, the EM signal can be adjusted depending on the input signals, meeting the requirements of AMOLED displays.

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16:15 - 16:30 Award Candidate (Paper Competition)
Manuscript ID.  0384
Paper No.  2023-FRI-S0702-O003
Yu-Hsuan Hsu Effects of ITO Contact Sizes on Performance of 40 μm and 10 μm Blue-Light MicroLEDs
Yu-Hsuan Hsu, Yi-Hsin Lin, Ray-Hua Horng, National Yang Ming Chiao Tung University (Taiwan)

In this study, the effect of contact ratio for blue light micro-light-emitting diode (μLED) with dimensions 40 μm and 10 μm were both assessed. As the contact ratio increased from 0.2 to 0.8, the turn-on voltage of μLEDs decreased and the leakage currents raised in both two dimensions devices. For optical properties, 40 μm μLED array with a 0.8 contact ratio presented the highest output power, which has the highest EQE value of 10.84%. However, the 0.5 contact ratio exhibited the highest EQE, 9.95%, in 10 μm μLED array. The simulation data using SpeCLED software agreed well with these experiments.

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16:30 - 16:45 Award Candidate (Paper Competition)
Manuscript ID.  0588
Paper No.  2023-FRI-S0702-O004
Chao-Che Wu Spiro-Acridine and Pyrimidine Bipolar Materials as TADF Host of TADF Emitters in an OLED
Chao-Che Wu, Han-Yun Szu, Chia-Hsun Chen, Man-Kit Leung, National Taiwan University (Taiwan); Tien-Lung Chiu, Yuan Ze University (Taiwan); Jiun-Haw Lee, National Taiwan University (Taiwan)

In this study, green thermally-activated delayed fluorescence (TADF) emitter was doped in a TADF host, consisting of the combination of acridine and pyrimidine units, and a spiro-ring structure, as the emitting layer (EML) of an organic light-emitting diode (OLED). By optimizing the doping concentration of the TADF emitter in the EML, maximum external quantum efficiency (EQEmax) of 11.73% was achieved, with Commission Internationale de l'Eclairage (CIE) coordinates at (0.321, 0.587). Notably, as the voltage was increased, the emission spectra displayed a distinct blue shift. Time-resolved electroluminescence (TrEL) measurements revealed prominent TADF characteristics, with a delayed emission time of 8 ms.

  Preview abstract
16:45 - 17:00 Award Candidate (Paper Competition)
Manuscript ID.  0596
Paper No.  2023-FRI-S0702-O005
Bang-Wei Huang Optimizing Luminous Efficiency through Phosphor-in-Glass Thickness Reduction
Bang-Wei Huang, Yu-Yuan Chang, Hsing-Kun Shih, Chun-Nien Liu, Wood-Hi Cheng, National Chung Hsing University (Taiwan)

In this experiment, We use sodium glass powder (SiO2-Na2O3-Al2O3-Ca2O), mixed with yellow phosphor powder (Y3Al5O12:Ce3+), and sintered at 700°C to form a glass phosphor. Through uniformity measurement Ensure that the difference in color coordinates is less than 3.9×1-3 after the four-inch wafer is cut into phosphor crystals. Finally, the PiG-80μm was tested at 250°C for 1008 hours and measured with an integrating sphere. Lumen loss is 1.3%, still maintaining high reliability physical characteristics. Therefore, the PiG with reduced thickness and reduced porosity in this study has high industrial value and can be applied to automobile lights.

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17:00 - 17:15 Award Candidate (Paper Competition)
Manuscript ID.  0685
Paper No.  2023-FRI-S0702-O006
Zi-Jia Huang Colloidal Quantum Dot LEDs Package With Porous Microcarrier
Zi-Jia Huang, Ching Chang, National Taiwan University (Taiwan); Guan-Teng Lin, Chung-Ping Huang, National Yang Ming Chiao Tung University (Taiwan); Chien-Chung Lin, National Taiwan University (Taiwan)

The porous structured microcarrier powders were mixed with CQD/PDMS packages to improve the dispersion of QD particles. Results show QDs intensity and PLQY of the containing microcarriers perform the more uniform light filed and slower decline rate under high QD dose conditions.

  Preview abstract
17:15 - 17:30 Award Candidate (Paper Competition)
Manuscript ID.  1049
Paper No.  2023-FRI-S0702-O007
Yu-Jui Chan Light Extraction Efficiency of Ultraviolet C AlGaN Light-Emitting Diodes
Yu-Jui Chan, Chia-Feng Lin, Chia-Lung Tsai, National Chung Hsing University (Taiwan)

Ultraviolet C AlGaN light-emitting diodes (UVC-LEDs) with an electrochemical (EC) treated hole array pattern were demonstrated. High electroluminescence (EL) emission images were observed in the UVC-LED with a hole array pattern. The EL emission peaks of the non-treated LED structure were measured at 277nm for AlGaN active layer and at 328 nm for the p-AlGN:Mg layer. By forming the EC-treated hole array pattern, the EL emission intensity of the treated LED was 1.8 times higher than that of the non-treated LED structure in the normal direction of the LED chips.

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S7. Display and Solid State Lighting

Display and Solid State Lighting III
Saturday, Dec. 2, 2023  10:45-12:00
Presider: Prof. Shun-Wei Liu (Ming Chi University of Technology, Taiwan)
Room: 92277 (2F)
10:45 - 11:15
Manuscript ID.  1092
Paper No.  2023-SAT-S0703-I001
Invited Speaker:
Jin Jang
A Study on Stretchable Active-Matrix Micro-LED Electronics
Jin Jang, Kyung Hee University (Taiwan)

I will talk about the issues related with stretchable AM electronics using oxide TFT array. I will discuss on the LTPO circuits for gate driver, EM gate driver, PWM pixel circuits for micro-LED displays. I will also discuss the transfer technology of micro-LEDs, and bonding to TFT array on stretchable PDMS substrate. We used the liquid metal for stretchable interconnection which is a key technology for stretchable electronics. The AM micro-LED display we have demonstrated could have 20% stretchability. I will conclude my talk by explain-ing some recent results on TFT electronics in ADRC.

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11:15 - 11:30
Manuscript ID.  0111
Paper No.  2023-SAT-S0703-O001
Yu-Ying Hung Ameliorating Uniformity and Color Conversion Efficiency of Blue and Quantum Well Intermixing UV Hybrid Micro-LED Display
Yu-Ying Hung, Tzu-Yi Lee, National Yang Ming Chiao Tung University (Taiwan); Wen-Chien Miao, Hon Hai Research Institute (Taiwan), National Yang Ming Chiao Tung University (Taiwan); Hao-Chung Kuo, National Yang Ming Chiao Tung University (Taiwan), Hon Hai Research Institute (Taiwan)

In this study, we used LightTools to simulate excitation of red and green quantum dots (QDs) and TiO2 QD photoresist by UV light from light-emitting diodes (LEDs). By fine-tuning QD and TiO2 concentrations and film thickness, we selected a QD film with 35% QD concentration, 17.5% TiO2, and 2 µm thickness. Simulation showed photoluminescence quantum yield of 57.8% for red and 45% for green QDs. For better color conversion efficiency, we added a multi-layer distributed Bragg reflector and combined red, green QDs with blue micro-LED for full-color display.

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11:30 - 11:45
Manuscript ID.  0491
Paper No.  2023-SAT-S0703-O002
Yulin Lin Regulating the triplet-triplet annihilation to fluorescence in polymer light-emitting diode
Yulin Lin, Mujahid1 Anas, Shi-Hong Luo, Chih-Ting Li, Tzung-Fang Guo, National Cheng Kung University (Taiwan)

Using magnetoelectroluminescence fingerprints, we observed significant triplet-triplet annihilation (TTA) processes in green poly(9,9-dialkylfluorene) derivative (G-PF)-based devices. TTA intensity was regulated through devices cathode structures. Adding a layer to block excitons increased triplet density and reduced metal cathode-induced quenching, improving TTA by 1.5 times. Importantly, the luminous efficiency also improved with the enhancement of TTA. Rational device design optimizes the advantages of TTA. In conclusion, TTA enhances the light emission of G-PF devices, thereby improving efficiency.

  Preview abstract
11:45 - 12:00
Manuscript ID.  0495
Paper No.  2023-SAT-S0703-O003
Anas Mujahid Magneto-electroluminescence Mediated by Magneto-conductance Polar Pair Model in Polymer and Thermally Activated Delayed Fluorescence Emitter-based Light Emitting Diodes
Anas Mujahid, Yulin Lin, Chih-Ting Li, Wei-Cheng Liu, National Cheng Kung University (Taiwan); Yi-Ting Lee, Soochow University (Taiwan); Tzung-Fang Guo, National Cheng Kung University (Taiwan)

Herein, we spectacle the precise technique to measure the magneto electro-luminance (MEL) by proposing a novel polaron pair model which depicts that positive magnetoconductance (MC) results directly from the polaron pairs dissociation and negative MC results from the triplet exciton charge reaction owing to the balanced and unbalanced device. Our model suggests that positive MEL results from the singlet exciton contributed to the positive MC. We validate our model by deploying it on the balanced and unbalanced light-emitting diodes (polymer and thermally activated delayed fluorescence based). We authenticate the MEL analysis is more trustworthy if measured at a constant current.

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S7. Display and Solid State Lighting

Display and Solid State Lighting IV
Saturday, Dec. 2, 2023  13:00-15:00
Presider: Prof. Kun-Yu Lai (National Central University, Taiwan) Prof. Chia-Yen Huang (National Yang Ming Chiao Tung University, Taiwan)
Room: 92277 (2F)
13:00 - 13:30
Manuscript ID.  0652
Paper No.  2023-SAT-S0704-I001
Invited Speaker:
Dong-Sing Wuu
Recent progress on advanced brightness enhancement films for display applications
Dong-Sing Wuu, National Chi Nan University (Taiwan)

The brightness enhancement film (BEF) has been widely used for displays, which deflects light rays toward
the normal direction and produces ray concentration and brightness enhancement effects. The typical BEF
structure is a prism with a 90-degree apex angle. To improve the visualization of displays, BEF is usually
combined with a diffusion layer or embedded with diffusion particles to achieve diffusion and better
visualization, which require post-processing or additional diffusion materials. In this study, we will present a
novel multifunctional optical film with nanoscale porosity features (pBEF). Micron-scale patterns are
distributed on the surface of pBEF, providing diffusion and visual modification functions. Nanoscale pores are
distributed in the inner layer of pBEF, which increase the transmittance of pBEF, reduce light recycling and
suppress color shift. Finally, the pBEF is applied to a direct type mini LED backlight unit, the brightness is
enhanced by a factor of up to 7% compared to the BEF incorporating dispersed particles and the color shift
∆xy is reduced by 15 - 40‰ compared to the regular BEF.

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13:30 - 13:45
Manuscript ID.  0890
Paper No.  2023-SAT-S0704-O001
Zong-Han Yang Secondary Optical Design of High Efficiency LED Direct-lit Lighting Board
Zong-Han Yang, Bo-Xiang Peng, Chi-Shou Wu, Tsung-Hsun Yang, Yeh-Wei Yu, Ching-Cherng Sun, National Central University (Taiwan)

This paper utilizes dual-die-encapsulated white LED as the light sources and employs a secondary optical design lens for application in a direct-type backlight panel. The designed lens in this study can decrease the number of light sources used in the direct-type backlight module, achieving a sparse arrangement effect. Furthermore, this study addresses the issue of the yellow halo phenomenon observed in practical samples. We propose a simplified blue-yellow light model, which helps explain the occurrence of the yellow halo phenomenon in real samples.

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13:45 - 14:00
Manuscript ID.  0080
Paper No.  2023-SAT-S0704-O002
Fu-He Hsiao Investigations on the high performance of InGaN red micro-LEDs with single quantum well structure
Fu-He Hsiao, Hon Hai Research Institute (Taiwan), National Yang Ming Chiao Tung University (Taiwan); Tzu-Yi Lee, National Yang Ming Chiao Tung University (Taiwan); Wen-Chien Miao, Hon Hai Research Institute (Taiwan), National Yang Ming Chiao Tung University (Taiwan); Yi-Hua Pai, Chun-Liang Lin, Chi-Wai Chow, National Yang Ming Chiao Tung University (Taiwan); Kazuhiro Ohkawa, King Abdullah University of Science and Technology (Saudi Arabia); Yu-Heng Hong, Hon Hai Research Institute (Taiwan); Chiao-Yun Chang, National Ocean University (Taiwan); Hao-Chung Kuo, Hon Hai Research Institute (Taiwan), National Yang Ming Chiao Tung University (Taiwan)

We have demonstrated the potential of InGaN-based red micro-LEDs for visible light communication. Our findings indicate that the sample with a single quantum well (SQW) structure performs better than InGaN red micro-LED with a double quantum wells structure. Furthermore, the SQW device has a superior modulation bandwidth with a higher data transmission rate. These results demonstrate that InGaN-based red micro-LEDs hold great promise for realizing full-color micro-display and visible light communication applications.

  Preview abstract
14:00 - 14:15
Manuscript ID.  0769
Paper No.  2023-SAT-S0704-O003
Nitzan Dar Optical Properties and Applications of Cyanine J-aggregates
Nitzan Dar, Rinat Ankri, Ariel University (Israel)

Cyanines are unique molecules whose absorption and emission can be shifted over a broad spectral range from the ultraviolet to the near infrared. They can readily transform into J-aggregates with narrow absorption and emission peaks accompanied by a red shift in their spectra. Due to their high absorption coefficient, they can be used as a layer in photovoltaics; moreover, their high absorption and emission properties and their advantage of increased tissue penetration depth can be used for bioimaging.

  Preview abstract
14:15 - 14:30
Manuscript ID.  0853
Paper No.  2023-SAT-S0704-O004
Pravinraj Selvaraj Versatile Energy-Efficient Smart Windows based on Self-Assembled Multistable Dynamic Scattering Mode
Pravinraj Selvaraj, Wen-Fa Cheng, Hsiu-Ming Kuo, Cheng-Kai Liu, Chao-Hsuan Wu, Chung Kung Lai, Jyun-Cong Lai, Sharon-Tan Fang-Jie, Ko-Ting Cheng, National Central University (Taiwan)

Here, we present novel self-assembled ionic liquid crystals (ILCs) doped with a negative cholesteric liquid crystal (CLCs) to offer electrically switchable and sustaining stable scattering mode light modulators based on dynamic fingerprint chiral textures (DFCT). The DFCT device can rapidly switch between stable transparent and stable scattering states by external stimuli, maintaining multistable states for extended periods, even after removing external stimuli. Furthermore, the DFCT device has polarization-independent scattering, transparent mode LC light modulators, low operating voltage, high contrast, wide viewing angles, and multistable full-color see-through windows.

  Preview abstract
14:30 - 14:45
Manuscript ID.  0874
Paper No.  2023-SAT-S0704-O005
Shao-An Chen Green Thermally Activated Delayed Fluorescence OLED Based on Acridine Derivative with Different Dopant Concentrations
Shao-An Chen, Fu-En Shi, Chia-Hsun Chen, Man-Kit Leung, National Taiwan University (Taiwan); Tien-Lung Chiu, Yuan Ze University (Taiwan); Jiun-Haw Lee, National Taiwan University (Taiwan)

In this research, a green thermally activated delayed fluorescence (TADF) emitter based on an acridine derivative was used in the emitting layer (EML) of an organic light-emitting diode (OLED) with a maximum external quantum efficiency (EQEmax) of 16.21% with CIE coordinates of (0.339, 0.584). From time-resolved electroluminescence (TrEL) measurements, a significant decrease in the delayed emission time was observed with increasing doping concentration.

  Preview abstract
14:45 - 15:00
Manuscript ID.  0302
Paper No.  2023-SAT-S0704-O006
Mu-Ju Wu Investigated aging test of blue/red micro-LEDs with various sizes
Mu-Ju Wu, Yi-Chun Lai, Shao-Yu Chu, Hsin-Ying Lee, National Cheng Kung University (Taiwan); Ching-Ting Lee, National Cheng Kung University (Taiwan), Yuan Ze University (Taiwan); Kai-Ling Liang, Wei-Hung Kuo, Industrial Technology Research Institute (Taiwan)

In this work, the gallium nitride (GaN)-based blue micro-light-emitting diodes (micro-LEDs) with various luminous areas of 15×15 and 9×9 μm^2 were fabricated. The red quantum dots (QDs) with and without titanium dioxide (TiO2) passivation layers were used as the color conversion layers to produce the red micro-LEDs. The TiO2 passivation layer was used to avoid the red QDs degraded by external environmental influences. After the aging test, the properties of the resulting blue and red micro-LEDs with various luminous areas driven by a constant current density of 667 A/cm^2 for 500 hr were measured and investigated.

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S7. Display and Solid State Lighting

Poster Session II
Saturday, Dec. 2, 2023  13:30-16:30
Room: Building of Electrical Engineering (電機系館) (B1)

Manuscript ID.  0863
Paper No.  2023-SAT-P0702-P001
Jia-Cheng Chen Effect of polymer networks and photoinitiators on liquid crystal structures
Jia-Cheng Chen, Yuan-Jang Tsai, Ko-Ting Cheng, National Central University (Taiwan)

This paper aims to investigate the widely accepted belief that polymer networks can stabilize LCs without deforming their structural characteristics such as tilt and twist angles. However, uncertainties remain regarding whether this stabilization affects the structural variations. To address this, we employed a twisted-hybrid LC (THLC) to analyze the impact of the polymer network on tilt and twist angles. Additionally, we explored the influence of the doping concentration of DMPAP on the LC structure. In this research, it can be concluded that the presence of DMPAP affects the twist angle, while the polymer network affects the tilt angle.

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Manuscript ID.  0078
Paper No.  2023-SAT-P0702-P002
Kuan-Hsuan Chen Broadband Double-layer Cholesteric Liquid Crystal Elastomer Films with Hyper-reflectivity
Kuan-Hsuan Chen, Chun-Ta Wang, Hyeonseok Lee, National Sun Yat-sen University (Taiwan); Yu-Chieh Cheng, National Taipei University of Technology (Taiwan)

In order to improve the optical performance of cholesteric liquid crystal elastomers (CLCEs), we have proposed a hyper-reflective CLCE film consisting of a two-layer structure. The two CLCE layers with helical structures of opposite handedness have the reflection spectra at the same position, but they reflect circularly polarized light with different handedness, resulting in high reflectivity. The results show that the reflection bandwidth of the original CLCE layer is broadened by the added CLCE layer.

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Manuscript ID.  0541
Paper No.  2023-SAT-P0702-P003
Chien-Lin Lin Investigation of High Brightness Blue Quantum Dot Light-Emitting Diodes with Hybrid Charge Transport Layers
Chien-Lin Lin, Chih-En Chang, National Yang Ming Chiao Tung University (Taiwan); Hsin-Chieh Yu, National Yang Ming Chiao Tung University (Taiwan), National Cheng Kung University (Taiwan)

In this study, blue quantum dot light-emitting diodes (QLEDs) comprised of
inorganic/organic hybrid charge injection/transport layers with solution-process was reported.
Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) was used as hole
injection layer (HIL), Poly-TPD as hole transport layer (HTL) and magnesium doped zinc
oxide nanoparticles (MgxZn1-xO NPs) with different magnesium mole fraction served as
electron transport layer (ETL) prepared by synthesis nanoparticles method were demonstrated.
The maximum luminance (Lmax) of the fabricated QLEDs can be up to 48,865 cd/m2 with
current efficiency of about 2.4 cd/A.

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Manuscript ID.  0690
Paper No.  2023-SAT-P0702-P004
GAUTHAM KUMAR KABBINAHITHLU Plasmonic Enhanced Photoluminescence of Perovskite Quantum Dots Using Gold Nanoparticles and Light-Emitting Applications
GAUTHAM KUMAR KABBINAHITHLU, FANG CHUNG CHEN, National Yang Ming Chiao Tung University (Taiwan)

Gold nanoparticles (NPs) are adopted to enhance the photoluminescent properties of perovskite quantum dots (QDs) and the localized surface plasmon resonance induced by the NPs effectively increases the efficiency of radiative recombination. The Au NPs are integrated as a photopatternable color conversion layer for micro-light-emitting diodes. The presence of Au NPs in the thin films does not affect the photolithography process.

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Manuscript ID.  0801
Paper No.  2023-SAT-P0702-P005
Hao-Jen Chang Small-Sized Indium Gallium Nitride Micro-LED Array With Atomic Layered Deposition Passivation
Hao-Jen Chang, Ke-His Chiang, Yu-Ming Jao, Chien-Chung Lin, National Taiwan University (Taiwan)

In this study, we fabricate different array sizes of square-shape Micro-LEDs and compare them with their performances, including electrical and photonic properties, to reveal a possible candidate of high power micro LED applications.

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Manuscript ID.  0706
Paper No.  2023-SAT-P0702-P006
Jin-San Shih Exciplex-forming System with Macrocyclic-based Donor for High Efficiency OLEDs
Jin-San Shih, National Taiwan University of Science and Technology (Taiwan); Dian Luo, Yi-Sheng Chen, Shun-Wei Liu*, Ming Chi University of Technology (Taiwan); Chih-Chien Lee*, National Taiwan University of Science and Technology (Taiwan)

Exciplexes, possessing similar characteristics with TADF emitters, have the potential to achieve a 100% IQE (Internal Quantum Efficiency), rendering them profoundly significant within the current research landscape. In this study, we extracted the donor component from a TADF material and combined it with two acceptor materials, CN-T2T and PO-T2T, to create exciplexes. Consequently, organic light-emitting diode (OLED) devices utilizing Donor:CN-T2T and PO-T2T blends as the emitter layer exhibited a maximum external quantum efficiency (EQE) of 9.39% and 11.03%, respectively.

  Preview abstract

Manuscript ID.  0870
Paper No.  2023-SAT-P0702-P007
Ke-Cheng Huang A Neural-Network Based Spectrum Generator for Multi-Channel LED Illuminator
Yu-Chen Cheng, Ke-Cheng Huang, Yi-Chun Chen, National Central University (Taiwan)

This study develops a spectrum generator for a 14-channel LED illuminator. Through genetic algorithms, a dataset is generated with corrected color temperature (CCT) of 3000K, 4000K and 5000K, and illuminance of 500 lx. The dataset includes lighting parameters such as CCT, Duv, general color rendering index (Ra) and circadian stimulus (CS), along with channel weights. Using this dataset, a neural network is trained. Results show that CS is affected by the blue-yellow color mechanism (b-y); the data of 4000K have lower CS than that of 3000K and 5000K. The spectrum generator can accurately produce spectra within the dataset’s parameter range.

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Manuscript ID.  0164
Paper No.  2023-SAT-P0702-P008
Zhi-An Lin Numerical Analysis and Optimization of InGaN-Based Red Light-Emitting Diodes with Delta-InN in the Active Region
Zhi-An Lin, Man-Fang Huang, Jih-Yuan Chang, Yen-Kuang Kuo, National Changhua University of Education (Taiwan)

InGaN-based light-emitting diodes with insertion of a delta-InN layer in the quantum well are investigated and optimized numerically using APSYS. By adjusting the indium content and the width of single InGaN quantum well, the aim is to design an optimized structure that can achieve a red emission wavelength of around 650 nm and maintain a high wall plug efficiency. The simulation results show that increase of carrier overlap in the quantum well is the key to enhance the device performance. The best wall plug efficiency is achieved with a quantum well composition of In0.32GaN and a width of 1.5 nm.

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Manuscript ID.  0294
Paper No.  2023-SAT-P0702-P009
Rong-Miao Chang High-brightness tandem white organic light-emitting diodes using a specific device architecture design
Rong-Miao Chang, Fong-Yu Yang, Song-Han Ou, Yu-Hsuan Chen, Chih-Hao Chang, Yuan Ze University (Taiwan)

OLEDs offer flexibility, thinness, durability, and non-directionality. However, OLEDs still lag in efficiency and brightness compared to inorganic LEDs. Tandem OLEDs exhibit higher efficiency and lifespan with multiple electroluminescence units connected through charge generation layers (CGLs). Herein, our purpose is to develop high-brightness tandem white OLEDs. To design our tandem white OLEDs, we introduced multi-alternating organic heterojunction (OHJ) structures in the CGL. The conventional white OLEDs achieved a maximum efficiency of 16.1% and a brightness of 63379 cd/m². Tandem devices with CGL containing four OHJ pairs achieved an efficiency of 34.5% (76.7 cd/A) and a brightness of 78657 cd/m².

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Manuscript ID.  0306
Paper No.  2023-SAT-P0702-P010
Guang-Ling Lee High Performance Poly-Si TFT with Structural Laser Crystallization Enhancement for Next Generation Display Technology Applications
Guang-Ling Lee, Industry Academia Innovation School, National Yang Ming Chiao Tung University (Taiwan); Tsung-Che Chiang, Zhen-Hao Li, Yu-Ting Tsai, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University (Taiwan); Po-Tsun Liu, Industry Academia Innovation School, National Yang Ming Chiao Tung University (Taiwan), College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University (Taiwan)

In this work, we demonstrate a improvement method of green laser crystallization (GLC) for poly-Si crystallization by depositing Ni before GLC. By increasing the grain size, the device exhibits higher field effect mobility (μFE) of 26.03 cm2/V-s, lower threshold voltage (VTH) of -0.4V than the device without depositing Ni before GLC, and remains great on/off current ratio (ION/IOFF) of 1.75e7.

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Manuscript ID.  0326
Paper No.  2023-SAT-P0702-P011
Yu-Ming Zhang High Performance Tin-doped Indium Zinc Oxide TFT for Ultra-high Resolution VR/AR Display Technology
Yu-Ming Zhang, Tsung-Che Chiang, Zhen-Hao Li, Zong-Han Wu, Po-Tsun Liu, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University (Taiwan)

In this work, a bottom gate TFT based on the sputter-deposited ITZO is investigated. For seeking the improved electrical properties, the variation of annealing temperature and oxygen partial pressure will be analyzed respectively. At an oxygen flow ratio of 1.4% and under 350°C annealing temperature for 30 minutes, the device exhibits a maximum on-off current ratio (ION/IOFF) of 1.46×108, a high mobility of 22.0 V/cm2∙s, a nearly ideal sub-threshold (S.S.) swing of 65.5 mV/dec., and a low leakage current of 1.11×10-12 ampere. Clearly, the electrical characteristics is highly beneficial for the applications for ultra-high resolution VR/AR display technology.

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Manuscript ID.  0699
Paper No.  2023-SAT-P0702-P012
Yi-Jia Li Deep Learning-based Image Quality Assessment for Subpixel Rendering Algorithm
Yi-Jia Li, Jun-Ying Lin, Chieh-En Lee, Chung-Hao Tien, National Yang Ming Chiao Tung University (Taiwan)

A subpixel rendering algorithm for GRGB micro-LED panel was proposed. We designed a linear transformation that can render high-resolution images through low-resolution panels while maintaining the image quality. To mimic the human perception on image quality, we conducted a deep learning-based merit. The result shows the proposed algorithm has better performance.

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Manuscript ID.  0037
Paper No.  2023-SAT-P0702-P013
Yo-Lin Chang Gate Driver on Array with Emission Signals for Application of Mini LEDs.
Yun-Chia Bao, Yo-Lin Chang, Guang-Ting Zheng, Po-Tsun Liu, National Yang Ming Chiao Tung University (Taiwan)

In this study, a high-reliability gate driver circuit (GOA) was designed using hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) for a 4.7-inch high-definition (1280xRGBx720) TFT-LCD panel. The gate driver circuit utilizes eight clock signals with a 50% signal overlap. This GOA circuit can provide both sequential square waves and simultaneous driving EM signals as inputs for the mini LED, resulting in a reduction in the number of ICs and signal usage, leading to cost savings and a smaller layout area. Finally, the proposed GOA underwent reliability testing and demonstrated excellent simulation results under strict simulation conditions (85°C and -40°C).

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Manuscript ID.  0039
Paper No.  2023-SAT-P0702-P014
Wen-Hui Chih Gate Driver On Array with Adjustable Pause Stage to Prevent Degradation for In-Cell Touch Liquid-Crystal Display
Si-Yu Huang, Wen-Hui Chih, Guang-Ting Zheng, Po-Tsun Liu, National Yang Ming Chiao Tung University (Taiwan)

This article proposed a new gate driver circuit using amorphous silicon (a-Si) for in-cell touch with time-division driving method (TDDM). Pre-charge node (Q node) could be pulled to the lowest level (VSS) during the touch period to prevent the long-term DC stress of driving TFT. The circuit could freely choose the touch stage. Therefore, the degradation of the node P[n] which is used to temporarily store the voltage during the touch stage could be evenly distributed. The simulation results show that the rising time and falling time are both less than 5us at 25 ℃.

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Manuscript ID.  0068
Paper No.  2023-SAT-P0702-P015
Shan-Yu Chen Highly-Efficient Polymer Color Conversion Hybrid Materials doped with Nanoparticles for Ultra-High Resolution Micro-LED Displays
Jian-Hong Lin, Yen-Chia Cheng, Shan-Yu Chen, Ching-Fuh Lin, National Taiwan University (Taiwan)

Micro light emitting diode (Micro-LED) display technology is considered the most promising display approach for the future. We have introduced the color conversion Micro-LED display, achieving a quantum yield and blue light absorption rate exceeding 70% and a conversion efficiency surpassing 50% through the integration of TiO2 nanoparticles (TiO2 NPs) with non-rare earth green luminescent materials. Our successful development of an efficient color conversion microarray allows for a single-color pixel density of up to 5080 PPI and a full-color pixel density of up to 2540 PPI. This significant research breakthrough offers a promising technological solution for manufacturing ultra-high-resolution Micro-LED displays.

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Manuscript ID.  0136
Paper No.  2023-SAT-P0702-P016
Chi-Shiang Chen Nonlinear Thermal Quenching Behavior of DCJTB Color Conversion Films
Chi-Shiang Chen, Chih-Yuan Tsai, Shan-Yu Chen, Chen-Hsun Wu, Ching-Fuh Lin, National Taiwan University (Taiwan)

This study investigates the impact of baking temperatures on the temperature tolerance of fluorescent dye (DCJTB) in the fabrication of color conversion films (CCF). In the experimental range of 50 to 150°C, we measured the quantum efficiency and absorbance of the thin films at different baking temperatures to understand the thermal quenching behavior of DCJTB. The results indicate an irreversible thermal quenching effect of DCJTB at high temperatures, primarily due to a reduction in the radiative recombination rate of charge-transfer excitons. Notably, the film exhibits the highest blue light absorption rate at 90°C, resulting in the optimal photon conversion efficiency.

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Manuscript ID.  0281
Paper No.  2023-SAT-P0702-P017
Guan-Wen Wang New Structure of Micro Light-Emitting Diode Color Conversion Layer Array with Color Purification
Guan-Wen Wang, Ching-Fuh Lin, National Taiwan University (Taiwan)

Micro-light-emitting-diode (Micro-LED) display is the future trend in displays. In the past, Micro-LED displays were produced using mass transfer techniques, facing challenges in the manufacture and the high cost. In this work, photolithography is used to create a 5080PPI high-resolution and efficient color conversion array. The novel Color Purity Enhancement Film (CPEF) structure further improves color purity and gamut range, with a Full width at half maximum of about 15nm and a gamut of 144% DCI-P3. Compared to traditional mass transfer, this research offers lower production costs and faster manufacturing. The technology holds potential for application in the metaverse.

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Manuscript ID.  0126
Paper No.  2023-SAT-P0702-P018
Shan-Yu Chen Utilizing negative photoresist solution with nanoparticles for ultra-high-resolution micro-LED displays
Shan-Yu Chen, Yen-Chia Cheng, Jian-Hong Lin, Chih-Yuan Tsai, Chen-Hsun Wu, Ching-Fuh Lin, National Taiwan University (Taiwan)

Doping nanoparticles (NPs) and red-green color conversion materials into transparent negative photoresist enhances the conversion efficiency (CE). By using mature semiconductor manufacturing process technology, a 4 x 4 um pixel array of red and green colors can be created. In the study, the single-color pixel density reaches 5080 pixels per inch (PPI), and the full-color pixel density reaches 2540 PPI. This lays the foundation for subsequent high-efficiency and high-resolution full-color conversion technology.

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Manuscript ID.  0582
Paper No.  2023-SAT-P0702-P019
Jing-Xiang Huang Near ultraviolet organic light emitting diode with different dopant concentrations
Jing-Xiang Huang, Chia-Hsun Chen, National Taiwan University (Taiwan); Jian-Haur Lee, Academia Sinica (Taiwan); Bo-Yen Lin, National Dong Hwa University (Taiwan); Chin-Ti Chen, Academia Sinica (Taiwan); Tien-Lung Chiu, Yuan Ze University (Taiwan); Jiun-Haw Lee, National Taiwan University (Taiwan); Yi-Ting Lee, Soochow University (Taiwan)

Near-ultraviolet organic light emitting diodes (OLEDs) were demonstrated with different dopant concentrations which showed a maximum external quantum efficiency (EQEmax) of 6.02% with electroluminescence (EL) emission peak of 394 nm and CIE coordinates of (0.161,0.042)

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Manuscript ID.  0478
Paper No.  2023-SAT-P0702-P020
Yu-Li Chang Chien Thin-Film Post-Hot Casting Annealing Deposition of Large-Area Perovskite Light-Emitting Devices Treated with Multifunctional Organic Molecule
Yu-Li Chang Chien, Jun-Qing Liu, Lung-Chien Chen, National Taipei University of Technology (Taiwan); Ching-Ho Tien, Ming Chi University of Technology (Taiwan)

High-quality large-area (4 cm2) perovskite CsPbBr2.5Cl0.5 doped with 2-amino-1,3-propanediol (APDO) material was prepared using post-hot casting annealing method. The photoluminescence wavelength of ADPO:CsPbBr2.5Cl0.5 perovskite shows cyan color at 508 nm. The ADPO:CsPbBr2.5Cl0.5 large-area perovskite LED exhibits a maximum luminance of 2660 cd/m2.

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Manuscript ID.  0678
Paper No.  2023-SAT-P0702-P021
Yi-Sin Cheng Electroluminescence Properties of Green InGaN nano-rod Light Emitting Diodes with Red Emission Light
Yi-Sin Cheng, Hongta Yang, Yu-Cheng Kao, Chia-Feng Lin, National Chung Hsing University (Taiwan)

Green InGaN-based nano-rod array light-emitting diodes (LEDs) has been demonstrated. Mono-layer of close-packed SiO2 sphere array with 250 nm diameter was used as the mask layer for the dry etching process. 50 um-diamer micro-LED with integrated nano-rods were fabricated through the ion-implantation process and top ITO layer. The electroluminescence (EL) emission wavelength was shifted from 513 nm for flat LED to 691.7 nm for nano-LED structure. The enlarging of the quantum confinement stack effect in the InGaN MQW active layers caused the redshift EL emission peak of the nano-rod LED.

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Manuscript ID.  0522
Paper No.  2023-SAT-P0702-P022
Chung-Kai Chi High Brightness Red Quantum Dots Light Emitting Diodes with MgZnO Electron Transport Layers
Chung-Kai Chi, National Yang Ming Chiao Tung University (Taiwan); Cheng-Tien Liu, Institute of Lighting and Energy Photonics, College of Photonics (Taiwan); Hsin-Chieh Yu, Institute of Lighting and Energy Photonics, College of Photonics (Taiwan), National Cheng Kung University (Taiwan)

In this study, we employed an inorganic/organic hybrid charge injection/transport layer and solution process to fabricate red quantum dot light-emitting diodes. By using MgZnO nanoparticles with different magnesium mole fraction as the electron transport layer, we observed remarkable operation performance enhancement with highest luminance of 479,536 cd/m² and maximum current efficiency of 9.69 cd/A.

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Manuscript ID.  0795
Paper No.  2023-SAT-P0702-P023
Chun-Wei Huang Light extraction of thin-film encapsulated OLED displays using 3D reflective pixel and angle-selective optical film
Po-Hsiang Liao, Wei-Kai Lee, Chang-Cheng Lee, Chun-Wei Huang, Sheng-Wen Wen, Yi-Ting Chen, National Taiwan University (Taiwan); Chung-Chia Chen, Wan-Yu Lin, B. Leo Kawk, Robert Jan Visser, Applied Materials (USA); Chung-Chih Wu, National Taiwan University (Taiwan)

In this work, influences of thin film encapsulation on light extraction of reflective 3D OLED pixels are considered by simulation studies, which unfortunately reveals strong reduction of the light extraction efficiency induced by TFE layers. As such, an additional angle-selective optical film between the pixel and the encapsulation layers is introduced to control the angular distribution of the light coupled into the encapsulation layers. As a result, TFE-induced losses can be substantially reduced to retain much of light extraction efficiency. The results of this study provide useful insights and guides for developing even more efficient and power-saving AMOLEDs.

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Manuscript ID.  0467
Paper No.  2023-SAT-P0702-P024
Chih-Hsuan Shih Color Vision Intelligent Inspection for Correcting Color Deficiency
Chih-Hsuan Shih, Fu Jen Catholic University (Taiwan); Yun-Ting Chiu, Taipei Medical University (Taiwan); Chia-Ying Tsai, Fu Jen Catholic University Hospital (Taiwan); Shao-Rong Huang, National Central University (Taiwan); Jin-Cherng Hsu, Fu Jen Catholic University (Taiwan), National Central University (Taiwan)

The research team has developed a color vision intelligent inspection aimed at human color discrimination. This system operates under the full-color gamut spectrum and features fast testing time, user-friendly operation, high sensitivity, and accurate detection of color blindness. The illumination system is equipped with a D65 light source with a power exceeding 100 Lux [1]. By passing light through a grating, it can generate 16 color sets for Farnsworth D-15 test, assessing color deficiencies comprehensively.
This innovative instrument can also simulate customized color correction glasses for patients, improving their condition through coating and wearing these glasses.

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Manuscript ID.  0189
Paper No.  2023-SAT-P0702-P025
Zhe-Chen Lin Low Voltage InZnSnO Photo-TFT with High Responsivity in the Visible Band and Fast Recovery by Using SubPc/Pentacene Light Absorbing Layers
Chun-Huag Kao, Zhe-Chen Lin, Ching-Lin Fan, National Taiwan University of Science and Technology (Taiwan)

In this paper, we reported a high-performance IZTO photo-TFT using heterojunction SubPc/Pentacene absorption layers. To reduce the operating voltage (VGS = -2 ~ 6 V and VDS = 3 V), we use high-k HfO2 as gate insulator. IZTO/SubPc/Pentacene heterojunction scheme can form well-organized band structure and interface characteristics in the visible band, to achieve a high responsivity of 25.5 A/W at 525 nm wavelength, and with a rise time of less than 50 ms and a fall time of less than 350 ms.

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Manuscript ID.  1100
Paper No.  2023-SAT-P0702-P026
Chi‑Ta Li Using Regrowth Crystal MAPbBr3 to Improve CsPbBr3 Perovskite Light-Emitting Diodes
Chi‑Ta Li, Sea‑Fue Wang, Kuan‑Lin Lee, Lung‑Chien Chen, National Taipei University of Technology (Taiwan)

The MAPbBr3 layer employed MAPbBr3 powder as the evaporation source, which was obtained from using MAPbBr3 bulk crystals prepared by the inverse temperature crystallization method. The devices exhibited the best quality and performance when a 20-nm-thick MAPbBr3 layer was used as the nucleation and hole transport layer. The rc-MAPbBr3/CsPbBr3 structure apparently boosted the carrier lifetime such that the injection holes and electrons quickly recombine and then transfer into photons and emissions. The champion luminescence and external quantum efficiency were 21850 cd/m2 at a bias of 7.0 V and 1.18% at a bias of 6.5 V, respectively.

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S7. Display and Solid State Lighting

Display and Solid State Lighting V
Saturday, Dec. 2, 2023  16:00-17:00
Presider: Prof. Jia-De Lin (National Dong Hwa University, Taiwan)
Room: 92277 (2F)
16:00 - 16:15
Manuscript ID.  1079
Paper No.  2023-SAT-S0705-O001
Sergiy Valyukh Highly Energy Efficient LCDs
Sergiy Valyukh, Kenneth Järrendahl, Linköping University (Sweden)

The lighting efficiency of conventional liquid crystal displays (LCDs) usually does not exceed 8-10% for a white screen and 4-5% when the screen image consists of equal numbers of bright and dark pixels. The present work is devoted to development of LCDs utilizing light recycling and multilayered birefringent structures acting as non-absorbing polarizing color filters. An analysis of the characteristics of such a LCD versus parameters of the color filters is carried out. We demonstrate that it is possible to reach the lighting efficiency up to 75% at contrast ratio 20:1 for any numbers of bright and dark pixels.

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16:15 - 16:30
Manuscript ID.  0115
Paper No.  2023-SAT-S0705-O002
Tien-Hung Peng A smart window that uses dye-doped cholesteric liquid crystal as an electrically tunable thermoresponsive optic switch
Yi-Cheng Chang, Tien-Hung Peng, Sheng-Hsiung Yang, Institute of Lighting and Energy Photonics (Taiwan); Wei Lee, Institute of Imaging and Biomedical Photonics (Taiwan)

We developed an electrically controlled and thermally responsive cholesteric liquid crystal (CLC) smart window that transitions from high transmission to low transmission state as the temperature increases, functioning as a tunable thermo-optic switch. This device combines thermoresponsive chiral dopants, a dichroic dye, and a nematic liquid crystal (LC) to create a thermosensitive CLC. As the temperature changes, the thickness/pitch ratio of the CLC bulk varies, and combined with the absorption characteristic of the dispersed dichroic dye, it creates transparent and opaque optical states. This passive mechanism requires no additional energy, resulting in energy efficiency, and can be enhanced by actively

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16:30 - 16:45
Manuscript ID.  0249
Paper No.  2023-SAT-S0705-O003
Ching-Han Yang Active planar chiro-optic devices with broadband tunability and invertible chirality
Ching-Han Yang, Pei-Ru Song, Chia-Rong Lee, National Cheng Kung University (Taiwan)

Photon-based communication has the potential to significantly expand information capacity due to its multi-dimensional properties. In this study, we utilized the photo-alignment technique to fabricate various geometrical phase elements doped with photo-responsive molecular motors. When the incident light's wavelength falls within the bandgaps of cholesteric liquid crystals (CLCs), the reflected light acquires geometrical phases depending on the morphology of the micro-patterned CLCs on the substrate. By controlling the concentrations of molecular motors with opposite handedness, we can tune both the working bands and polarization handedness of the reflected beams, resulting in a high degree of freedom in tailoring light’s properties.

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16:45 - 17:00
Manuscript ID.  0118
Paper No.  2023-SAT-S0705-O004
Pei-Ching Wei Thermally adaptive polymer-stabilized cholesteric texture windows without surface orientation treatment
Yu-Xian Lin, Institute of Imaging and Biomedical Photonics (Taiwan); Pei-Ching Wei, Institute of Photonics System (Taiwan); Wei Lee, Institute of Imaging and Biomedical Photonics (Taiwan); Guan-Fu Sung, College of Photonics (Taiwan)

We propose a novel self-adaptive switchable device of a thermally responsive polymer-stabilized liquid crystal (LC) that alters transmittance levels based on the SmA–N* phase transition. Through photopolymerization subject to a curing voltage, a polymer network is formed to create the homeotropic configuration of the SmA phase in a cell, eliminating the need for an alignment layer. As the temperature rises, the LC bulk transforms to a disordered N* texture. The SmA–N* phase transition enables reversible self-switching of the polymer-stabilized cholesteric LC cell between the transparent and haze states. The proposed device presents a promising avenue for advanced technologies in

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S7. Display and Solid State Lighting

Display and Solid State Lighting VI
Sunday, Dec. 3, 2023  09:00-11:00
Presider: Prof. Chih-Hao Chang (Yuan Ze University, Taiwan) Prof. Tsung-Hsien Lin (National Sun Yat-sen University, Taiwan)
Room: 92277 (2F)
09:00 - 09:30
Manuscript ID.  1076
Paper No.  2023-SUN-S0706-I001
Invited Speaker:
Tae-Woo Lee
Perovskite Nanocrystals for High-Efficiency, Stable and Large-area Light-Emitting Diodes
Tae-Woo Lee, Seoul National University (Korea)

Metal halide perovskites (MHPs) are potential next-gen display emitters due to high color
purity and affordability. Despite their promise, they still trail existing LEDs in efficiency and
stability. This presentation discusses commercialization strategies for MHPs. We introduce a
material strategy to suppress defect formation in perovskite nanocrystals (PNC). Techniques
include doping with guanidinium for improved carrier confinement and using a bromine-based
molecule for halide vacancy healing. A modified-bar coating allows for efficient large-area
applications. Moreover, an in-situ core/shell PNC structure boosts efficiency and device
lifetime by enhancing charge transport and confinement

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09:30 - 09:45
Manuscript ID.  0407
Paper No.  2023-SUN-S0706-O001
Chen-Da Du Applying Surface Plasmon Resonance to 355-nm Ultraviolet Light Emitting Diodes
Chen-Da Du, National Central University (Taiwan), Academia Sinica (Taiwan); Kun-Yu Lai, National Central University (Taiwan)

355-nm UV LEDs were grown on sapphire substrates. The devices were fabricated with Al electrodes on the p-GaN contact layer with varied thickness. According to photoluminescence (PL) measurements, it was observed that the LED device exhibited the surface plasmon resonance (SPR) effect when the Al electrode and AlGaN multiple quantum well (MQW) were separated by 50-nm of p-GaN (grown for 5 minutes).

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09:45 - 10:00
Manuscript ID.  0067
Paper No.  2023-SUN-S0706-O002
Tsun-Han Wang Thermo-responsive smart glass
Tsun-Han Wang, Shie-Chang Jeng, National Yang Ming Chiao Tung University (Taiwan)

Nearly 40% of global energy is consumed in buildings, of which windows are the least energy-efficient one in building envelopes. An eco-friendly aqueous solution with surfactant is applied as the thermo-responsive dimmers to solve both of the solar radiant and privacy.

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10:00 - 10:15
Manuscript ID.  0246
Paper No.  2023-SUN-S0706-O003
Meng-Shu Rao Optimization of EL Intensities in Hybrid 2-D WSe2/AlGaInP Light Emitting Device through Dielectric Layer Thickness Engineering
Meng-Shu Rao, Ya-Hui Chang, Yen-Shou Lin, Academia Sinica (Taiwan), National Yang-Ming Chiao-Tung University (Taiwan); Konthoujam James Singh, Academia Sinica (Taiwan); Min-Hsiung Shih, Academia Sinica (Taiwan), National Yang-Ming Chiao-Tung University (Taiwan)

Multi-wavelength light-emitting devices have significant applications in various fields, such as displays and optical communication systems. In this study, we investigated the optimization of electroluminescence (EL) intensities in hybrid 2-D WSe2/AlGaInP quantum wells light-emitting devices with different thicknesses of AlOx layer. Increasing the AlOx thickness resulted in higher threshold voltages and reduced EL intensities ratio between GaP-based multiple quantum wells (MQWs) and WSe2 monolayer, offering the potential for optimized full-color light emitting devices.

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10:15 - 10:30
Manuscript ID.  0343
Paper No.  2023-SUN-S0706-O004
Yu-Min Chang Sub-pixel-matched meta-collimator array design for micro-light-emitting diode display
Yu-Min Chang, Teng-Li Shao, Wen-Hsuan Hsieh, Tien-Chiu Chen, Hung-Chang Hsieh, Yao-Wei Huang, Tien-Chang Lu, Chia-Yen Huang, National Yang Ming Chiao Tung University (Taiwan)

We proposed a metasurface collimator array made of GaN circular pillars, whose span matched the sub-pixel of a 3000 pixel-per-inch micro-light-emitting diode (μ-LED) display. Finite-difference time-domain simulation revealed the well-designed meta-collimator could narrow the divergence angle from 118 degree to 4.8 degree. The integrated intensity within ±10 degree divergence could be enhanced 13.6-fold after capping the μ-LED display with the subpixel-matched meta-collimator array with an optimized airgap in between.

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10:30 - 10:45
Manuscript ID.  0355
Paper No.  2023-SUN-S0706-O005
Jo-Hsiang Chen High quality Liquid-type White Light-emitting Diode with Zn0.8Cd0.2S White Quantum Dots
Jo-Hsiang Chen, Tsung-Sheng Kao, Hao-Chung Kuo, National Yang Ming Chiao Tung University (Taiwan)

In this study, liquid-type WQDs were demonstrated to be highly efficient color conversion layers in UV LED packaging. We designed a glass box to protect the white light Zn0.8Cd0.2S (Zn0.8 for short) quantum dot material, keeping it in a liquid state to improve the luminous efficiency and reliability of WQD-based devices. The luminous efficiency, color rendering index (CRI) and correlated color temperature (CCT) of the liquid-type white QD LED (LWQD-WLED) are 332lm/Wop, higher than 80 and 4360K, respectively. Furthermore, the ultrahigh reliability of the devices means progress towards the superior performance of commercially viable solid-state lighting.

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S7. Display and Solid State Lighting

Poster Session III
Sunday, Dec. 3, 2023  09:00-11:00
Room: Building of Electrical Engineering (電機系館) (B1)

Manuscript ID.  0540
Paper No.  2023-SUN-P0703-P001
HOI WAI CHOI Phosphor-free InGaN white LED by nanostructuring with random clusters of mono-sized nanospheres
WAI YUEN FU, HOI WAI CHOI, University of Hong Kong (Hong Kong)

In this study, a novel method for fabricating phosphor-free InGaN-based LEDs using cost-effective nanosphere lithography with mono-sized nanospheres is introduced. The induction of various degrees of spectral blue-shift is known to occur when nanopillars of different sizes are fabricated, a phenomenon attributed to the reduction of the Quantum Confined Stark Effect. In this work, a distribution of nanopillar clusters resulting in a broadband white emission, is realized by controlling the concentration of the mono-sized nanosphere solution. Under current operation, white emission is achieved with a color rendering index of 76.

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Manuscript ID.  0220
Paper No.  2023-SUN-P0703-P002
Pei-Chi Tsai Rose Petal Structure Patterning on Phosphor Layer for Improving the Angular Color Uniformity of pcLEDs
Pei-Chi Tsai, Bing-Mau Chen, Shang-Ping Ying, Minghsin University of Science and Technology (Taiwan)

In this study, the rose petal surface structure on the surface of phosphor layer of the phosphor converted light-emitting diodes (pcLEDs) was fabricated to reduce the angular color variation. The two-step fabrication process was used to fabricate the rose petal surface structure on the surface of phosphor layer directly. It is found that the rose petal surface structure on the surface of phosphor layer on pcLEDs can reduce the angular color variation, and then improve the color uniformity.

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Manuscript ID.  0876
Paper No.  2023-SUN-P0703-P003
Tsung-Chou Tsai Enhanced optical stability of the titled-twist state in a chiral nematic π-cell
Shun-Yi Chiu, Institute of Imaging and Biomedical Photonics (Taiwan); Tsung-Chou Tsai, Institute of Photonic System (Taiwan); Jy-Shan Hsu, Department of Physics (Taiwan); Wei Lee, Institute of Imaging and Biomedical Photonics (Taiwan)

The effects of doping a small amount of chiral dopant S811 into a binary liquid crystal (LC) mixture of CB7CB and E55 have been thoroughly investigated. Due to the unique molecular structure of the LC dimer CB7CB, it influences various properties, including changes in dielectricity, flexoelectricity, and elastic constant, resulting in the emergence of distinct optical states. These modifications contribute to shorter response times in LC displays and improved optical stability in the left-handed tilted-twist state.

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Manuscript ID.  0999
Paper No.  2023-SUN-P0703-P004
Jin Ho Park Enhanced Performance of Pixelated Quantum Dot Light-Emitting Diodes by controlling ZnO Uniformity using Inkjet Printing Process
Jin Ho Park, Woo Jin Jeong, Hee Jung Kwak, Kiguye Collins, Jun Young Kim, Gyeongsang National University (Korea)

In this report, we studied Inkjet Printing of Zinc Oxide(ZnO), a material normally used as the Electron Transport Layer(ETL) in Quantum-Dot Light Emitting Diode(QLED). To improve the uniformity of the deposited ZnO film through inkjet printing in pixels using a co-solvent system. so, the Flatness ratio(Fr) of Zinc Oxide Nanoparticle (ZnO NP) Ink in D was initially observed to be 0.3. the addition of the co-solvent lowered Fr to 0.01. And, the External Quantum of Efficency(EQE) of fabricated QLED increased from 1.5% to 3.2% as the uniformity of the ZnO film improved.

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Manuscript ID.  1041
Paper No.  2023-SUN-P0703-P005
Seok Je Lee Effects of Molecular Ordering on the Electrical Properties of Polymer Organic Light-Emitting Diode
Seok Je Lee, Woo Young Kim, Chul Gyu Jhun, Hoseo University (Korea)

We explained the mechanism of the molecules ordering by the different coating method. The emission layer (EML) of organic light-emitting diode (OLED) was fabricated by the spin coating method and bar coating method, respectively. By the bar coating method, the organic molecules within the EML are aligned. We verified the correlation between molecular ordering and device performance based on various analyzes such as complex dielectric anisotropy and molecular crystallinity. The electro-optical characteristics of the OLED device were quantitatively compared.

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Manuscript ID.  0005
Paper No.  2023-SUN-P0703-P006
Hung-Chung Li Optimal light sources and an evaluation model for improving the visual color perception of cosmetic colors
Hung-Chung Li, National Chung Hsing University (Taiwan); Hsin-Pou Huang, Chihlee University of Technology (Taiwan)

The study investigates how the light source's illuminance, correlated color temperature (CCT), distance to the black-body locus (Duv), and color rendering indices (CRI) affect the user's perceptual attributes when viewing cosmetic color. The results show that a light source design with a high illuminance level, high CCT, high color rendering, and Duv=0 or -0.02 is beneficial to improving the three perceptual attributes.

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Manuscript ID.  1061
Paper No.  2023-SUN-P0703-P007
Seok Je Lee The Enhanced Electro-Optical Properties of Organic Light-Emitting Diode with Nanoparticles
Seok Je Lee, Woo Young Kim, Chul Gyu Jhun, Hoseo University (Korea)

To improve electro-optical performance, we propose metal oxide nanoparticles on anode of organic light-emitting diode (OLED). When metal oxide nanoparticles are coated on the anode, the work function of the anode changes. We calculated the change of the work function of the anode, which improve the hole injection performance of OLED.

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Manuscript ID.  0603
Paper No.  2023-SUN-P0703-P008
Yan-Fang Lai Characterization of white light LED by a home-built hyper spectrometer
Hung Ji Huang, Yan-Fang Lai, National Formosa University (Taiwan)

The hyperspectral imaging technology successfully inspects the throughput spectra of the white and warm white LEDs at various positions by a home-built instrument. The results present the difference in diffuse and conversion efficiency of various phosphors in white and warm white LEDs from the data of various light throughput at the center and the side positions of the main light-delivering spot.

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Manuscript ID.  1027
Paper No.  2023-SUN-P0703-P009
Chan-Chi Lin Electro-optical properties of polymer stabilized cholesteric liquid crystals doped with bent-shape molecules
Mei-Chuan Chiang, Tien-Jung Chen, Chan-Chi Lin, National Taipei University of Technology (Taiwan)

A polymer-stabilized cholesteric liquid crystals (CLCs) doped with bent-shape molecules was studied. Applied with a vertical electric field, the proposed CLCs can be converted from a stable ULH state to the other stable state, addressed as a mixed state. The dopant of bent-shape molecules in CLCs affects the electro-optical properties of the mixed state and the ULH state. The mixed state is investigated by polarized optical microscope (POM), while the ULH state is measured about its rotation angle to evaluate the flexoelectric effect.

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Manuscript ID.  1035
Paper No.  2023-SUN-P0703-P010
Pei-Jung Wu The Investigation of Objective Visual Fatigue Evaluation under Different Classroom Lighting Environments
Pei-Jung Wu, National Taichung University of Science and Technology (Taiwan); Ching-Ju Chou, Chien-Yu Chen, National Taiwan University of Science and Technology (Taiwan); An-Pin Wei, National Taichung University of Science and Technology (Taiwan)

With students’ class needs and physiological and psychological health as the core, students’ visual fatigue in blue light with different band composition under the same white light (same color temperature 4000K) and different desk illuminance (400lx and 700lx) is discussed. In this study, the blink rate is as the parameter of the objective visual fatigue. The results found the subjects in 400lx white light environment have more visual fatigue than in 700lx white light environment and they have less visual fatigue in the while light with blue pumps of 420nm.

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Manuscript ID.  0434
Paper No.  2023-SUN-P0703-P011
Yen-Ru Chen Study on the Impact of Different Contact Ratios on the Characteristics of Red Micro-LED Device Components
Yen-Ru Chen, Po-Hsiang Wang, Po-Liang Liu, Dong-Sing Wuu, National Chung Hsing University (Taiwan)

This study explores the difference in different pixel contact ratio using AlGaInP epitaxial material for fabrication of 80x80 μm² pixel size. Single devices are arranged in a 3x3 pixel array, and micro-LEDs are fabricated with different contact ratios (0.8, 0.6, 0.4, and 0.2) between the cathode metal (AuGe/Au) and the n-GaAs layer. Flip-chip bonding is employed for backside light emission measurements to eliminate light obstruction caused by metal deposition and enhance light extraction efficiency. Discuss the results separately for the four contact ratio, including current-voltage characteristics, light output power, external quantum efficiency, and electroluminescence spectral analysis.

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Manuscript ID.  1066
Paper No.  2023-SUN-P0703-P012
Jian-Ting Wu Evaluation of Static Work Concentration under Different Correlated Color Temperature and Circadian Stimulus
Jian-Ting Wu, Yi-Chun Chen, National Central University (Taiwan)

This study investigates users’ concentration under different lighting scenarios. Genetic algorithms are used to generate specific lighting spectra with different correlated color temperatures and circadian stimulus. An electroencephalogram device is used to measure the brainwaves during the psychophysical experiments. Subjective assessments are obtained via questionnaires. The signal processing of acquired brainwaves includes the time-frequency analysis using Hilbert-Huang transform, and the time-domain analysis characterized by the fractal dimension obtained from the Higuchi method.

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Manuscript ID.  0622
Paper No.  2023-SUN-P0703-P013
Hsin-Pou Huang Visual Comfort of a Head-up Display under Dark Condition
Hsin-Pou Huang, Chihlee University of Technology (Taiwan); Hung-Chung Li, National Chung Hsing University (Taiwan); Hung-Wen Dao, Bo-Yu Lin, Chihlee University of Technology (Taiwan)

A psychophysical experiment is devised to explore the impact of differences in text-background brightness on visual comfort while using a head-up display in dark condition. Sixty participants are taking part in this experiment, with a balanced distribution of 20 individuals in each of the following age groups: young, middle-aged, and older participants. Each observer is tasked with evaluating a total of 190 paired comparisons. The results show that the older observers tend to prefer the lightness difference around 100, however, the young observers tend to prefer the lightness difference around 50 when reading on the head-up display.

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Manuscript ID.  0567
Paper No.  2023-SUN-P0703-P014
Ke-Peng Chang Fabrication of Microlens Array with Light Shaping for Laser Scanning Smart Headlights
Ke-Peng Chang, Kuo-Yin Huang, National Chung Hsing University (Taiwan), Taiwan Color Optics Inc. (Taiwan); Yung-Peng Chang, Taiwan Color Optics Inc. (Taiwan); Chun-Nien Liu, Wood-Hi Cheng, National Chung Hsing University (Taiwan)

We present an innovative microlens array (MLA) as an optical diffuser for laser scanning smart headlights. The MLA achieves uniform energy distribution, overcoming the "hot spot" issue. By precise glass etching control, beams with FWHM divergence from 5° to 34° were fabricated. This advancement holds promise for enhancing laser scanning smart headlight performance and autonomous vehicle technology.

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Manuscript ID.  0524
Paper No.  2023-SUN-P0703-P015
Szu-An Chen Enhancing luminescence efficiency in small-sized micro light-emitting diodes using digital etching technology
Szu-An Chen, Jian-Jang Huang, Hung-Yi Chiang, Yi-Kai Jin, National Taiwan University (Taiwan); Kuan-Heng Lin, Chia-An Lee, AU Optronics Corporation (Taiwan)

We propose a digital etching technology that employs multi-step etching and
treatment to mitigate sidewall defects exposed after mesa dry etching. In this study, by twostep etching and N2 treatment, the electrical properties of the diodes show an increase of
forward current and a decrease in reverse leakage due to suppressed sidewall defects. We also
demonstrated only 1.1% decrease in output power density for a 10×10-µm2 LED as compared
with a 100×100-µm2 device without performing digital etching.

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Manuscript ID.  0055
Paper No.  2023-SUN-P0703-P016
Hao-Chuan Chang The Analytical Model for the System Stability of the Lighting System Applying Organic Light-Emitting Diode
Henglong Yang, Jun-Hong Chen, Hao-Chuan Chang, National Taipei University of Technology (Taiwan)

We applied control theory to analyze the stability issues of the lighting system with degradable organic light-emitting diode (OLED) by system characteristics. Our simulation result of system parameters indicated that the close-loop control with feedback and compensation is essential to improve the system stability as OLED intrinsically degraded.

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Manuscript ID.  0186
Paper No.  2023-SUN-P0703-P017
Jun-Wei Wu Analysis of Device Variation Effect in MicroLED Display Driven by Pulse Width Modulation with Gamma Correction
Jun-Wei Wu, Wei-Lin Wu, Ya-Hsiang Tai, National Yang Ming Chiao Tung University (Taiwan)

This study examines a popular TFT-based microLED (μLED) pixel circuit using pulse width modulation (PWM) driving and explores its device variation tolerance. It highlights the importance of compensating for both threshold voltage and mobility, revealing challenges in achieving gamma 2.2 in PWM pixel circuits.

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Manuscript ID.  0042
Paper No.  2023-SUN-P0703-P018
Ji-Hoon Choi Fluoropolymer encapsulated perovskite quantum dots for air-stable color conversion devices
Ji-Hoon Choi, Joo Yeon Kim, Electronics and Telecommunications Research Institute (Korea), University of Science and Technology (Korea); Hyunsu Cho, Electronics and Telecommunications Research Institute (Korea); Stephy Jose, Electronics and Telecommunications Research Institute (Korea), University of Science and Technology (Korea); Jaehyun Moon, University of Science and Technology (Korea), Electronics and Telecommunications Research Institute (Korea); Chan-Mo Kang, Sukyung Choi, Dae-Hyun Ahn, Koo-Joo Kim, Jin-Wook Shin, Jae-Eun Pi, Electronics and Telecommunications Research Institute (Korea)

Perovskite quantum dots (PeQDs) have the advantage of narrow FWHM, high PLQY and high absorption coefficient. However, PeQDs are easily decomposed oxygen and moisture due to their ionic bonding structure. To solve this problem, PeQDs are encapsulated with PFPE-based fluoropolymer resin. Crosslinked fluoropolymer matrix prevents decomposition of PeQDs owing to blocking oxygen and moisture. PeQD color conversion layers are fabricated on blue OLED devices. In this study, the fabricated green and red devices retained their initial PL intensity of ~72% and ~100% over 100 days, respectively.

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Manuscript ID.  0517
Paper No.  2023-SUN-P0703-P019
Chee-Keong Yee Measurement of Red AlGaInP-based micro-LED Arrays with Light Output Enhancement Using Surface Roughness
Chee-Keong Yee, Prechatavanich Natchanon, Ming-June Wu, Chao-Hsin Wu, National Taiwan University (Taiwan)

The AlGaInP-based red micro light-emitting diode (micro-LED) arrays in 620nm wavelength are demonstrated in our works. The micro-LED arrays with 10x10 pixels in 13x20 mesa size were fabricated which achieved enhancement with surface treatment and light improvement with surface roughness We also measured and comparing the characteristics of micro-LED arrays with and without the surface roughness in (NH4)2Sx passivation treatment.

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Manuscript ID.  0406
Paper No.  2023-SUN-P0703-P020
Yun-Cheng Hsu Arsenic Ion Implantation Effect on Performance of Micro-Light Emitting Diodes Array
Xin-Dai Lin, Yun-Cheng Hsu, Ray-Hua Horng, Institute of Electronics Engineering (Taiwan)

The LED arrays define the light-emitting area using multi-energy arsenic ion implantation, all with the same light-emitting area. As the pixel size reduces (from 50×50 μm² 1 pixel to 5×5 μm² 100 pixels), LOP and EQE decrease. Based on PL analysis, we assume that this reduction is due to light absorption by defects caused by ion implantation. Assuming a higher sidewall surface ratio for smaller pixel sizes, the defect density increases, resulting in lower LOP and EQE. Despite not achieving the elimination of sidewall effects, the micro-LED arrays still maintain excellent electrical performance and EL uniformity.

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Manuscript ID.  1053
Paper No.  2023-SUN-P0703-P021
Seok Je Lee Color Conversion Method to Expand the Emission Spectrum of Linearly Polarized Organic Light-Emitting Diode
Seok Je Lee, Woo Young Kim, Chul Gyu Jhun, Hoseo University (Korea)

To fabricated a linearly polarized OLED, not only the hole transport layer must be used as an alignment layer, but also the molecules of the emission layer (EML) must have a liquid crystalline phase. Since the EML material with a liquid crystalline phase is limited so the emission spectrum of linearly polarized OLED is also limited. We fabricated linearly polarized OLEDs that emit green and blue light, respectively. Using the emission spectra of two different colors, we propose a simulation algorithm in the color coordinates depending on concentration conditions.

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Manuscript ID.  0159
Paper No.  2023-SUN-P0703-P022
Shing-Hong Hou Al-based local surface plasmonic resonance in ultraviolet spectral region with wavelength tunability
Shing-Hong Hou, Hung-Chang He, Tien-Chiu Chen, Jhih-Sheng Wu, Chia-Yen Huang, National Yang Ming Chiao Tung University (Taiwan)

Tuning the local surface plasmon resonance (LSPR) peak to UVC spectral region is
important to achieve plasmonic-enhanced AlGaN-based light-emitting diodes. In this study, we
chose the height of aluminum nano-rod and the thickness of underlying SiO2 spacer as the major
tuning parameters for extinction spectrum. We observed that reducing the height of aluminum
nano-rod height to 50 nm~ 60 nm effectively brings the LSPR peak to UVC spectral region, and
the peak wavelength be fine-tuned with SiO2 spacer thickness.

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Manuscript ID.  0160
Paper No.  2023-SUN-P0703-P023
Wei-Lin Wu Power and Color Shift Analysis of Driving MicroLED Display with Gamma 2.2 Correction in Low Grayscale
Wei-Lin Wu, Jun-Wei Wu, Ya-Hsiang Tai, National Yang Ming Chiao Tung University (Taiwan)

This study examines the performance of HPP drivers in terms of power and color shift at low grayscale, and further investigates the impact of PPI variation on product applications. Based on the quantified results of power and color shift, these findings serve as reference factors for early-stage circuit design.

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Manuscript ID.  0584
Paper No.  2023-SUN-P0703-P024
Tsung-Chih Wan Improving the luminous performance of GaN-based micro-LEDs through KOH texturing and laser lift-off
Tsung-Chih Wan, Institute of Electronics (Taiwan); Yu-Yun Lo, Hsiao-Wen Zan, Department of Photonics, College of Electrical and Computer Engineering, (Taiwan); Ray-Hua Horng, Institute of Electronics (Taiwan)

In order to enhance the luminous efficiency of GaN-based micro-LED and the poor heat dissipation performance of sapphire substrate, flip-chip bonding and laser lift off technology were adopted to remove the sapphire substrate, and simultaneously form GaN thin-film. The gallium atoms generated after laser lift off are etched by HCl:H2O = 1:1 at room temperature for reducing the light radiated from MQW to be absorbed. The 4 M of KOH etching at 50 ℃ for 1 min and 2 min makes the output power and EQE of the GaN-based blue micro-LED be improved.

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Manuscript ID.  1034
Paper No.  2023-SUN-P0703-P025
XinYu Lin Reducing degradation ability of Quasi-2D over MAPbBr3 (3D) Perovskite Light-Emitting Diodes
XinYu Lin, Tzung-Fang Guo, Thi-Hoai Do, college of science (Taiwan)

In recent years, organometal halide perovskite light-emitting diodes (LEDs) have attracted widespread attention due to rapid advances in device efficiency. However, rapid degradation under continuous operation is one of the major issues limiting perovskite light-emitting diode (PeLED) technology. In general, ion migration is the most important source of PeLED degradation. Therefore, under this background, this experiment uses transient ion drift to study the role of ion migration in MAPbBr3 perovskite and quasi-two-dimensional perovskite.

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Manuscript ID.  1037
Paper No.  2023-SUN-P0703-P026
Pei-Sheng Hsieh Two-photon polymerization of chiral nematic liquid crystals
Pei-Sheng Hsieh, Cheng-Ying Wu, Yu-Hua Chou, Jia-De Lin, National Dong Hwa University (Taiwan)

Chiral nematic liquid crystal is nematic liquid crystal with chirality; thus, the molecules tend to rotate helically. The inherent helical structure of chiral nematic liquid crystal results in various optical features, such as optical activity, Bragg diffraction, and scattering, depending on the orientations of the molecules. In this work, we aim to modulate the molecular arrangements of polymer-stabilized chiral nematic liquid crystals and thus their optical features by two-photo polymerization direct laser writing (2PP-DLW). The influence of the writing parameters on the polymer-stabilized chiral nematic liquid crystals is discussed.

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Manuscript ID.  1047
Paper No.  2023-SUN-P0703-P027
Yi-Hong Tsai Birefringence measurement of the ULH cholesteric liquid crystals
Yi-Hong Tsai, Tien-Jung Chen, National Taipei University of Technology (Taiwan)

The uniform lying helix (ULH) structure formed by cholesteric liquid crystals (CLCs) has a negative optical birefringence, different from that of nematic liquid crystals (NLCs) commonly used in displays.
NLCs have a positive birefringence, while negative birefringence often requires a special molecular structure, such as discotic LC molecules.
In this study, CLCs composed of different constituents were used to form the stable ULH state.
We measure the phase difference of the ULH structure and calculate the corresponding birefringence.

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Manuscript ID.  1111
Paper No.  2023-SUN-P0703-P028
Tse-Jui Chen Tröger base scaffold introduces carbazole for application in green Organic Light-emitting Diodes
Tse-Jui Chen, Tunghai University, (Taiwan)

Tröger’s base containing carbazole was designed and synthesized to serve as a host material for phosphorescent organic light-emitting diode (OLED) applications. Tröger's base is C2 symmetric, offering high Tg values (171–211°C) for thermal stability. Its unique V-shaped twisted structure has been used to create amorphous host materials for OLEDs with high thermal stability. From the tests, it has been determined that it can serve as a green phosphorescent host for Ir(ppy)3, achieving an EQE of 11.8% and a Von dropping to 2.6V, showcasing commendable efficiency. In the future, through component improvements, even better efficiency is expected.

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Manuscript ID.  1136
Paper No.  2023-SUN-P0703-P029
Cong-Yuan Chou Distributed Computing Design for Augmented Reality System of Tour Bus
Cong-Yuan Chou, Yung-Jhe Yan, National Yang Ming Chiao Tung University (Taiwan); Chieh-Han Yang, Tzu-Yi Yu, Chun Yen Huang, Yu Hsiang Tsai, ndustrial Technology Research Institute (Taiwan); Mang Ou-Yang, National Yang Ming Chiao Tung University (Taiwan)

The augmented reality system primarily integrates virtual information into the sight
of an observer to achieve an augmented reality effect.Multiple augmented reality systems can
be applied to a tour bus. How to effectively allocate hardware resources for accelerating the
computation speed is a key issue when the computing power of each augmented reality system
is limited.Thus,this paper intends to accelerate the computation speed of the augmented reality
system using a distributed computing framework.In the experiment,one host device shares
image frames with the other two client devices for object detection. The computation speed
using two and three devices is approximately 1.4and1.8 times that of a single device.

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