Article
Chemistry, Multidisciplinary
Desui Chen, Luying Ma, Yunhua Chen, Xiaoqi Zhou, Shiyu Xing, Yunzhou Deng, Yanlei Hao, Chaodan Pu, Xueqian Kong, Yizheng Jin
Summary: The study identifies a previously overlooked efficiency-loss channel, namely interfacial exciton quenching induced by surface-bound ethanol, in ZnO-based electron-transporting layers (ETLs). By using a surface treatment procedure to replace the redox-active ethanol with electrochemically inert alkali carboxylates, the electrochemical stability of the ZnO ETLs is improved, resulting in higher efficiency and longer operational lifetime of quantum-dot light-emitting diodes (QLEDs). This work provides crucial guidelines for designing ZnO-based ETLs in optoelectronic devices.
Article
Optics
Katarzyna Pieniak, Witold Trzeciakowski, Grzegorz Muziol, Anna Kafar, Marcin Siekacz, Czeslaw Skierbiszewski, Tadeusz Suski
Summary: The study examined electroluminescence from In0.17Ga0.83N/GaN quantum wells of LEDs and LDs, finding a transition from ground-states recombination to excited states recombination with increasing QW width. The effect is accompanied by partial or complete screening of the built-in electric field with increasing driving current, which was studied using a high pressure method. Investigations were supported by simulations of the variation with driving current of electron and hole wavefunctions overlap affecting the recombination channel and built-in electric field.
Article
Chemistry, Multidisciplinary
Zishan Yan, Tong Chen, Lingpeng Yan, Xinghua Liu, Jingxia Zheng, Fu-de Ren, Yongzhen Yang, Bin Liu, Xuguang Liu, Bingshe Xu
Summary: White-light emitting carbon dots (WCDs) with high color rendering index (CRI) were prepared through a one-step solvothermal reaction. The WCDs emit white light by combining red, yellow, green, and blue lights. The high CRI value of 97 achieved in WLEDs using the WCDs as phosphors is among the highest reported. Additionally, multicolor LEDs can be fabricated using the four multicolor CDs as phosphors.
Article
Thermodynamics
Mary Low, Yew M. Hung, Ming K. Tan
Summary: We investigated the use of plasma-activated water for enhancing heat transfer in LED cooling. By replacing deionized water with plasma-activated water, a significant increase in heat transfer coefficient and illuminance was achieved. This enhancement can be attributed to the presence of reactive oxygen and nitrogen species in the plasma-activated water that reduce surface tension and minimize surface oxidation.
APPLIED THERMAL ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Islam Mohammad Shafiqul, Raj Deep, Jie Lin, Toshiyuki Yoshida, Yasuhisa Fujita
Summary: In this study, nitrogen-doped zinc oxide nanoparticles were successfully synthesized using the gas evaporation method with DC arc plasma. The nitrogen concentration was found to have an impact on the Raman spectra and photoluminescence spectra of the nanoparticles.
Article
Optics
Jacob J. Ewing, Cheyenne Lynsky, Matthew S. Wong, Feng Wu, Yi Chao Chow, Pavel Shapturenka, Michel Iza, Shuji Nakamura, Steven P. Denbaars, James S. Speck
Summary: This article studied the method of achieving highly efficient long-wavelength InGaN LEDs through V-defect engineering, which utilized naturally occurring V-defects for lateral injection and improved the external quantum efficiency.
Article
Chemistry, Physical
Islam Mohammad Shafiqul, Toshiyuki Yoshida, Yasuhisa Fujita
Summary: Heterojunction light-emitting diodes (LEDs) based on p-type ZnO and n-type ZnMgO nanoparticles have been successfully fabricated. The experimental results show that the LEDs with the p-ZnO/n-ZnMgO/GZO structure exhibit better I-V characteristics and lower leakage current compared to the p-ZnO/GZO LEDs, and the emission intensity is improved by adding the ZnMgO NP layer.
Review
Optics
Mahdiyar Nouri Rezaie, Shahram Mohammadnejad, Shabnam Ahadzadeh
Summary: The review paper discusses various hybrid inorganic/organic light-emitting diodes (I/O LEDs) based on zinc oxide (ZnO) and conjugated polymers, analyzing their structural, electrical, and optical characteristics and applications. Optoelectronic features of these hybrid LEDs are influenced by n-type ZnO nanostructures, and their electroluminescent intensity can be enhanced by selecting suitable p-type conjugated polymers or adding dopants. Challenges, comparisons, and future prospects of these hybrid LEDs, including the use of nanotubes, quantum dots, and perovskite layers, have also been explored.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Physics, Applied
Zheng Chen, Jintao Wang, Jingquan Lin, Ying Shen, Muwei Wang, Yu Duan
Summary: To enable the rolling and folding of OLEDs, a flexible encapsulation layer is needed to protect the organic materials and metal electrodes. By optimizing the composition and stress gradient of the deposited films, better flexible encapsulation can be achieved. Testing showed that OLEDs with stress gradient encapsulation structure performed well after bending 10000 times, indicating promising applications in bendable and wearable products.
APPLIED PHYSICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Long Gao, Tuo Cheng, Lijie Gou, Yilin Zhang, Yuping Liu, Long Yuan, Xiaoyu Zhang, Yinghui Wang, Fanxu Meng, Jiaqi Zhang
Summary: By adding OctBr ligands to the surface of Cl/Br mixed perovskite NCs, surface light loss and ion migration pathways are effectively reduced, resulting in CsPbCl1.5Br1.5 NCs with exceptional blue emission. The study identified the nature of surface defects and proposed a surficial modification approach for developing high-performance and color-stable blue mixed-halide perovskite LEDs.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Fang Zhang, Hao Min, Ya Zhang, Zhiyuan Kuang, Jiaqi Wang, Ziqian Feng, Kaichuan Wen, Lei Xu, Chao Yang, Haokun Shi, Chunxue Zhuo, Nana Wang, Jin Chang, Wei Huang, Jianpu Wang
Summary: Tin-based perovskites show great potential to replace toxic lead-based materials in optoelectronic applications. However, the slow development of tin perovskite LEDs is hindered by the challenge of obtaining high-quality tin perovskite films. This study introduces a vapor-assisted spin-coating method to achieve high-quality tin perovskites and high-efficiency LEDs.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Xiangyu Fu, Yash Mehta, Yi-An Chen, Lei Lei, Liping Zhu, Nilesh Barange, Qi Dong, Shichen Yin, Juliana Mendes, Siliang He, Renuka Gogusetti, Chih-Hao Chang, Franky So
Summary: The study demonstrates highly directional and polarized light emission from LEDs by selectively diffracting the TE waveguide mode, showing potential for more efficient photonic applications.
ADVANCED MATERIALS
(2021)
Article
Multidisciplinary Sciences
Po-Wei Chen, Po-Wen Hsiao, Hsuan-Jen Chen, Bo-Sheng Lee, Kai-Ping Chang, Chao-Chun Yen, Ray-Hua Horng, Dong-Sing Wuu
Summary: The mechanism of carrier recombination in downsized mu-LED chips was investigated, showing that the smallest chip size exhibited the highest ideality factor due to carrier recombination in high-defect-density zones. The use of a passivation layer and a maskless technology improved the performance and efficiency of the mu-LED chips. The blue-shift phenomenon in the electroluminescence spectrum was attributed to carrier screening and band filling effects, with high EQE values observed in the high current density region for the 10 x 10 μm(2) mu-LED chip.
SCIENTIFIC REPORTS
(2021)
Review
Physics, Applied
Zhe Zhuang, Daisuke Iida, Kazuhiro Ohkawa
Summary: InGaN-based LEDs are efficient light sources in the blue-green range, but their efficiency decreases when extending to the red region, posing a challenge for integrating red, green, and blue LEDs for full-color micro-LED displays. This review summarizes the recent progress in InGaN-based red LEDs of various chip sizes, including epitaxial structures, device fabrication, and optical performance.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Review
Materials Science, Multidisciplinary
Saeedeh Mokarian Zanjani, Francesco Tintori, Sadra Sadeghi, Pavel Linkov, Sergey Dayneko, Afshin Shahalizad, Hamid Pahlevaninezhad, Majid Pahlevani
Summary: Recent improvements in efficiency and luminance of quantum-dot light-emitting diodes (QLEDs) offer a versatile technology for next-generation lighting and display applications. Advances in colloidal quantum-dot (CQD) synthetic methods and charge balance engineering have played a key role in these developments. This review summarizes the engineering improvements of ZnO-based electron transport layers (ETLs), highlighting significant enhancements achieved through various defect passivation methods.
ADVANCED PHOTONICS RESEARCH
(2022)
