Article
Chemistry, Multidisciplinary
Yu Zhang, Rana Biswas
Summary: A promising approach to enhance light outcoupling in OLEDs is to utilize internal periodic corrugations that can diffract waveguided and plasmonic modes back to the air cone. Conformally corrugated OLEDs with a photonic crystal substrate exhibit high light outcoupling efficiency around 60-65% and an enhancement factor exceeding 3 for optimal pitch values between 1 and 2.5 μm. Plasmonic losses remain below 10% for all corrugation pitch values, providing a pathway for achieving high light outcoupling over the full optical spectrum.
Article
Chemistry, Multidisciplinary
Jia Chen, Pingchuan Ma, Wenjing Chen, Zhengguo Xiao
Summary: Photon recycling plays a significant role in increasing the outcoupling efficiency of perovskite light-emitting diodes. Experimental results demonstrate that with the photon recycling effect, the external quantum efficiency (EQE) of PeLEDs can remain above 15%, showing a significant improvement compared to devices without PR.
Article
Materials Science, Multidisciplinary
Yungui Li, Naresh B. Kotadiya, Bas van der Zee, Paul W. M. Blom, Gert-Jan A. H. Wetzelaer
Summary: This study presents a numerical model to simulate the optical outcoupling efficiency of OLEDs with a broad recombination zone, demonstrating that single-layer OLEDs can achieve high outcoupling efficiency similar to multilayer OLEDs. The simulations are validated with experiments on OLEDs of different thickness, showing potential for efficient, stable, and simplified OLED designs.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Jae-Min Kim, Kyu Young Hwang, Sungmin Kim, Junseop Lim, Byungjoon Kang, Kum Hee Lee, Byoungki Choi, Seung-Yeon Kwak, Jun Yeob Lee
Summary: The external quantum efficiency (EQE) of OLEDs can be improved by controlling the light-emitting dipole orientation (EDO) through the design of new phosphorescent materials. This study demonstrates that by modifying the molecular structure of the phosphorescent emitter, the EDO can be effectively enhanced. The results show a linear relationship between EDO and the aspect ratio, and the enhancement of EDO is mainly attributed to the vertical alignment of the molecule's C3 axis.
Article
Chemistry, Multidisciplinary
Wenjing Chen, Jia Chen, Lianghui Gu, Zongming Huang, Pingchuan Ma, Yihan Zhang, Hui Liu, Hongmin Zhou, Nana Wang, Jianpu Wang, Zhengguo Xiao
Summary: The external quantum efficiency of planar-structure perovskite light-emitting diodes (PeLEDs) can be enhanced by forming textured perovskite films. By manipulating the dwell time of antisolvents, the film surface roughness and haze can be controlled, resulting in increased light outcoupling and boosted EQE.
ADVANCED MATERIALS
(2022)
Article
Optics
Haotao Li, Shiming Zhou, Shuming Chen
Summary: This study realizes top-emitting quantum-dot light-emitting diodes (QLEDs) with an outcoupling efficiency of over 45% by optimizing the thicknesses of indium-zinc-oxide (IZO) phase tuning layers and IZO top transparent electrodes simultaneously. Moreover, by applying a scattering layer on the IZO top electrode, the red QLEDs show record-breaking efficiencies of EQE 44.5%, power efficiency 92.2 lm W-1, and current efficiency 93.7 cd A(-1).
LASER & PHOTONICS REVIEWS
(2023)
Article
Materials Science, Multidisciplinary
Yidenekachew J. Donie, Dominik Theobald, Somayeh Moghadamzadeh, Adrian Mertens, Ihteaz M. Hossain, Ulrich W. Paetzold, Uli Lemmer, Guillaume Gomard
Summary: In this work, the extraction of waveguided and substrate modes in organic light emitting diodes (OLEDs) is improved by using compact light scattering layers composed of TiO2 nanopillars. The fabrication process allows for internal light outcoupling elements with limited parasitic absorption and easily tunable light scattering properties. Efficiency enhancement and ameliorated angular emission characteristics are demonstrated in a monochromatic bottom emitting OLED. This approach can be integrated in high-throughput fabrication routine and extended to other OLED layouts.
ADVANCED OPTICAL MATERIALS
(2021)
Review
Chemistry, Physical
Feisong Qin, Min Lu, Po Lu, Siqi Sun, Xue Bai, Yu Zhang
Summary: Perovskite light-emitting diodes (PeLEDs) show great potential for next-generation display and lighting applications due to their excellent optoelectronic properties. However, a systematic overview of the luminescence and degradation mechanisms is currently lacking. This study provides a detailed discussion of the photophysical processes, electroluminescence mechanism, and device degradation of perovskite materials and PeLEDs. Strategies to improve device performances, including optimization of photoluminescence quantum yield, charge injection and recombination, and light outcoupling efficiency, are also summarized. This work aims to guide future development of PeLEDs and facilitate their industrial applications.
Article
Engineering, Electrical & Electronic
Qing Ci, Xingang Ren, Yeqiang Yan, Hao Ren, Kaikun Niu, Guoxing Sun, Zhixiang Huang, Xianliang Wu
Summary: Perovskite light-emitting diodes (PeLEDs) have gained considerable research interest in recent years due to their decent and tunable optoelectronic characteristics. By incorporating nanopatterns, PeLEDs not only exhibit substantial improvement in light extraction intensity, but also reveal remarkable directivity, with the emission angle continuously engineered over 65 degrees. This work is of great importance for engineering highly directional and efficient luminescence devices.
IEEE PHOTONICS JOURNAL
(2021)
Article
Multidisciplinary Sciences
Jin-Hoon Kim, Jin-Woo Park
Summary: An intrinsically stretchable organic light-emitting diode, made of highly stretchable constituent materials, is able to emit light under strains as large as 80%. It has a low turn-on voltage of 8 V and a maximum luminance of 4400 cd m(-2) from both the anode and cathode sides. The device can withstand repeated stretching cycles up to 200 times and shows improved light-emitting efficiency with small stretches up to 50%.
Article
Optics
Bo -Yen Lin, Ya-Xun Lin, Shao-Ju Lin, Yi-Yen Lin, Su-Hua Chen, Mao-Kuo Wei
Summary: The use of self-assembly microlens array films (MAFs) made of silica microspheres and acrylic resin significantly improves the light extraction efficiency (LEE) and angular-spectrum stability of organic light emitting diodes (OLEDs). The MAFs, fabricated through a simple and cost-effective spin-coating process, have a high fill factor of 71.42% and exhibit high transmittance (86.2-90.6%) and high haze (78.9-82.4%) in the UV-Vis regime. The incorporation of MAFs enhances the external quantum efficiency (EQE) of OLEDs by 66% compared to reference OLEDs, while maintaining a small angular shift of CIE-indices and a wide viewing angle range.
JOURNAL OF LUMINESCENCE
(2023)
Article
Physics, Applied
Yungui Li, Qi-Ran Li, Paul W. M. Blom, Gert-Jan A. H. Wetzelaer
Summary: This study demonstrates that top-emitting organic light-emitting diodes using a thin Au/Ag top electrode can achieve high light-outcoupling efficiency and reduce spectral narrowing compared to thick silver electrodes. Tuning the organic capping layer thickness can achieve this without affecting the electrical properties, and can be applied to both intrinsic and doped charge transport layers.
APPLIED PHYSICS EXPRESS
(2021)
Article
Multidisciplinary Sciences
Sudhir Kumar, Tommaso Marcato, Frank Krumeich, Yen-Ting Li, Yu-Cheng Chiu, Chih-Jen Shih
Summary: The authors demonstrated the control of transition-dipole-moment orientation in quantum dot solids using colloidal lead halide perovskite anisotropic nanocrystals, leading to an enhanced external quantum efficiency.
NATURE COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Yungui Li, Bas van der Zee, Gert-Jan A. H. Wetzelaer, Paul W. M. Blom
Summary: The study combines electrical and optical model calculations to demonstrate that the light-outcoupling efficiency in PLEDs is influenced by electron traps and the anisotropy factor of optical dipoles. Electron trapping confines recombination near the cathode, resulting in strong optical trapping in surface plasmon polariton modes.
ADVANCED ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Physical
Haotao Li, Fengshou Tian, Shuming Chen
Summary: By synergistically optimizing the optical and electrical performances, the efficiency of quantum-dot light-emitting diodes (QLEDs) can approach the theoretical limit. With the introduction of a high refractive index indium zinc oxide (IZO) electrode and the optimization of its thickness, the light outcoupling efficiency is significantly improved, resulting in an external quantum efficiency (EQE) of 33.2% for red QLEDs. By using a high refractive index plastic substrate and a microlens array, the EQE can be further improved to a record value of 37.5%.
Article
Materials Science, Multidisciplinary
Jinfei Dai, Chenjing Zhao, Jie Xu, Hossein Roshan, Hua Dong, Francesco Di Stasio, Fang Yuan, Bo Jiao, Zhaoxin Wu
Summary: In this study, the performance of perovskite nanocrystal light emitting diodes (PNC-LEDs) was enhanced through rational device structure design and the application of high-performance perovskite nanocrystal emitting layers.
ORGANIC ELECTRONICS
(2024)
Article
Materials Science, Multidisciplinary
Jia-Hua Yeh, Suhendro Purbo Prakoso, Leon Lukhas Santoso, Shi-Ju Chen, Bryan Chiang, Ju-Chieh Cheng, Ru-Ning Zhang, Yu-Cheng Chiu
Summary: This study demonstrates the application of a renewable material called dextrin-SMS in the production of electret filters and transistor memory. Dextrin-SMS material can maintain prolonged electrostatic charges and has a relatively wide memory window, making it suitable for the production of biodegradable face masks and green electronics.
ORGANIC ELECTRONICS
(2024)
Article
Materials Science, Multidisciplinary
Ahmad Telfah, Qais M. Al-Bataineh, Ahmad A. Ahmad, Rund Abu-Zurayk, Carlos J. Tavares, Johannes Etzkorn, Farzad Foadian
Summary: Polyacrylic acid complexed with polyaniline (PAA/PANI) composite materials have the potential to form organic mixed ion-electron conductive (OMIEC) films, which can be used in optoelectronic and energy storage applications. The composite films are formed through an acid-base reaction, resulting in strong electrostatic interactions and intermolecular hydrogen bonds between PANI and PAA. The separation of PANI-rich domains from PAA-rich matrix in the composite films is observed. The electrical conductivity of the composite films is higher when the content of PANI is 33 wt%, due to the high ionic-electronic coupling at the interface between phase-separated regions.
ORGANIC ELECTRONICS
(2024)
Article
Materials Science, Multidisciplinary
Min-Chih Hou, Dian Luo, Yu-Ting Huang, Shun-Wei Liu, Chin-Wei Lu, Chih-Hao Chang, Hai-Ching Su
Summary: Light-emitting electrochemical cells (LECs) have great potential for novel emission applications, but their relatively low device efficiency hinders their competitiveness with other emission technologies. A study finds that increasing the concentration of small TiO2 nano-particles in the diffuser film can enhance light extraction and improve the device efficiency of LECs.
ORGANIC ELECTRONICS
(2024)
Article
Materials Science, Multidisciplinary
Qiaoli Niu, Yao Xu, Jun Yang, Wei Hua, Baoxiang Chai, Zequan Zhang, Yuhui Ma, Wenjin Zeng, Ana Flavia Nogueira, Ruidong Xia
Summary: By introducing CPB as a defect passivation agent in the perovskite precursor solution, the optoelectronic properties of perovskite films can be significantly improved and non-radiative carrier recombination can be effectively suppressed. CPB-modified perovskite solar cells exhibit lower trap-state density and stronger carrier migration capability, leading to enhanced power conversion efficiency and stability.
ORGANIC ELECTRONICS
(2024)
Article
Materials Science, Multidisciplinary
Hulya Ozturk Dogan, Fatma Yildirim, Zeynep Orhan, Ali Ben Ahmed, Mostefa Benhaliliba, Sakir Aydogan
Summary: In this study, efficient self-powered visible and UV photodetectors based on hybrid organic-inorganic materials were demonstrated. The photodetectors showed excellent UV detecting capability and good photoresponsivity.
ORGANIC ELECTRONICS
(2024)
