Review
Chemistry, Inorganic & Nuclear
Jayaraman Jayabharathi, Venugopal Thanikachalam, Shanmugam Thilagavathy
Summary: This review presents a low-cost fabrication process for efficient phosphorescent organic light-emitting diodes (PhOLEDs) based on Ir(III) complexes. The excellent charge transportation and injection abilities of Ir (III) complexes contribute to their usage as both charge transport materials and emissive materials in PhOLEDs. The reduced intermolecular aggregation and excellent hole and electron transporting abilities of Ir(III) complexes lead to highly efficient PhOLEDs. In doped PhOLEDs, the efficiency is determined by exciton confinement, charge trapping, and dopant concentration.
COORDINATION CHEMISTRY REVIEWS
(2023)
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, Inorganic & Nuclear
Zheng-Guang Wu, Bing Yang, Yu-Chen Qiu, Yang Wang, Hong Dai, You-Xuan Zheng, Yi Wang, Lanping Hu, Yi Pan
Summary: Cyclometalated iridium (Ir)(iii) complexes are currently the most promising emitters for OLEDs. Two novel blue Ir(iii) complexes were designed to achieve blue emission and good electron mobility simultaneously, showing improved electroluminescence performances. This provides an effective strategy for the future molecular design of blue Ir(iii) complexes with good electron transport property for OLEDs.
DALTON TRANSACTIONS
(2021)
Article
Optics
Qi Zhu, Liang Zhou, Weiqiang Liu, Yingjie Cui, Ruixia Wu, Jiahai Wang, Qingduo Duanmu
Summary: An efficient blue organic electroluminescent device was achieved by optimizing the double light-emitting layers structure, selecting appropriate host materials, and adjusting the doping concentration. The device exhibited good thermal stability and high current efficiency, making it a promising candidate for practical applications in the field of optoelectronics.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Jingwen Yao, Wei Liu, Chengwei Lin, Qian Sun, Yanfeng Dai, Xianfeng Qiao, Dezhi Yang, Jiangshan Chen, Dongge Ma
Summary: Fluorescent white organic light-emitting diodes (WOLEDs) with high efficiency, low-efficiency roll-off, and long lifetime were achieved through strategic control of the position of phosphor-sensitized fluorescent yellow emitter. Singlet excitons are utilized for blue emission and triplet excitons for yellow emission in optimized WOLEDs, demonstrating great potential for practical applications.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Physical
Kiun Cheong, Unhyeok Jo, Wan Pyo Hong, Jun Yeob Lee
Summary: A blue tetradentate Pt(II) complex named Pt-tmCyCz is developed by introducing a cycloalkyl unit fused to carbazole to improve the rigidity and bulkiness of the complex. The complex exhibits high external quantum efficiency, narrow full width at half maximum, and stable spectrum in OLEDs.
Review
Chemistry, Multidisciplinary
Mengxin Xu, Xinyi Li, Shihao Liu, Letian Zhang, Wenfa Xie
Summary: Near-infrared (NIR) light-emitting devices with emission wavelengths ranging from 700 nm to 2500 nm have gained significant interest for various applications. This review focuses on molecular design strategies for NIR materials, recent advancements in highly luminescent NIR materials, structural designs and underlying device physics of high-performing NIR organic light-emitting devices (OLEDs), practical applications in biomedicine and component determination, as well as current limitations and prospects for the development of NIR materials, devices, and applications.
MATERIALS CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Inorganic & Nuclear
Li-Li Wen, Chun-Xiu Zang, Ying Gao, Guang-Fu Li, Guo-Gang Shan, Xin-Long Wang, Kui-Zhan Shao, Wen-Fa Xie, Zhong-Min Su
Summary: In this study, high-quality white organic light-emitting diodes (WOLEDs) were constructed by designing compounds of Ir(III) phosphors and regulating the substituent moieties and pi conjugation of the chelated ligands. The resulting WOLEDs demonstrated superior performance and a low roll-off ratio compared to commercial green Ir(ppy)(2)acac and Ir(ppy)(3) in the same device configuration.
INORGANIC CHEMISTRY
(2022)
Review
Optics
Shi-Jie Zou, Xin-Yi Zeng, Yan-Qing Li, Jian-Xin Tang
Summary: WOLEDs, especially SEL-WOLEDs, are considered promising candidates for full-color display and solid-state lighting due to their high efficiency, white color balance, simple fabrication, and large-area manufacturing possibilities. Recent strategies focus on molecular design, energy transfer mechanisms, and combining different emitters to improve device performance in SEL-WOLEDs. Future prospects and technological challenges of SEL-WOLEDs are also discussed.
LASER & PHOTONICS REVIEWS
(2021)
Article
Nanoscience & Nanotechnology
Asim Onal, Guncem Ozgun Eren, Sadra Sadeghi, Rustamzhon Melikov, Mertcan Han, Onuralp Karatum, Melek Sermin Ozer, Houman Bahmani Jalali, Itir Bakis Dogru-Yuksel, Iskender Yilgor, Onder Metin, Sedat Nizamoglu
Summary: In the next decade, a majority of conventional light sources will be replaced by LEDs. Quantum dots are considered to have high potential for future LED technology because of their sensitive band-gap tuning, high PLQY, and mass-production capacity. This study successfully demonstrated high-performance white LEDs using quantum dots, showing their promise for next-generation lighting devices.
Article
Chemistry, Analytical
Qing Zhao, Dongfang Zhao, Xinchen Zhang
Summary: We successfully demonstrated efficient simplified orange and white organic light-emitting devices using a platinum(II) complex Tetra-Pt-N. The maximum current efficiency achieved from the optimized orange device was 57.6 cd/A. The emission mechanism of Tetra-Pt-N doped into 4,4'-bis(arbazole-9-yl)biphenyl was discussed. Moreover, a high-efficiency and simplified white device was fabricated by introducing an ultra-thin blue phosphorescent emission layer. The white device with a maximum current efficiency of 41.9 cd/A showed excellent stable spectra and low efficiency roll-off.
Article
Chemistry, Multidisciplinary
Chen Zhang, Dongdong Zhang, Zhengyang Bin, Ziyang Liu, Yuewei Zhang, Hyuna Lee, Jang Hyuk Kwon, Lian Duan
Summary: A novel double-emissive-layer device architecture is proposed in this study to capture hole-trapping TADF-sensitized emissions, achieving tunable colors and accelerated exciton emission dynamics for high efficiency. The WOLEDs demonstrate significant shifts in color coordinates and correlated color temperatures under various luminance conditions, maintaining high external quantum efficiency even at high brightness levels.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Applied
Hyung Jin Cheon, Chul Woong Joo, Da Yeon Lee, Gunel Huseynova, Jae-Hyun Lee, Jonghee Lee, Yun-Hi Kim
Summary: A new iridium complex based on (4-(3,5-dimethylphenyl)-2-(m-tolyl)pyridine) was synthesized for highly efficient orange phosphorescent organic light-emitting diodes (PhOLEDs). The introduction of a methyl substituent into the 4-position of the phenyl ring in a phenylpyridine chelating ligand was found to significantly improve the performance of PhOLEDs. The newly-synthesized iridium complex exhibited maximum external quantum and current efficiencies of 20.33% and 61.16 cd/A, respectively, with these values maintained even at high luminance levels.
Article
Materials Science, Multidisciplinary
Chao Shi, Hong Huang, Qiuxia Li, Jingwen Yao, Cuicui Wu, Yibo Cao, Fangxiang Sun, Dongge Ma, Hong Yan, Chuluo Yang, Aihua Yuan
Summary: The study describes a novel strategy towards a series of charged ligand-based neutral iridium(III) complexes with adjustable color emission from blue-green to near-infrared. These complexes show excellent chemical and thermal stability, making them suitable for OLED devices with high external quantum efficiency, low efficiency roll-off, and turn-on voltage. This research provides new opportunities for optoelectronic applications of novel phosphorescent iridium(III) complex materials with tunable properties.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Kai Chen, Ruixia Wu, Xiaokang Li, Weiqiang Liu, Zhipeng Wei, Jiahai Wang, Liang Zhou
Summary: By precisely optimizing the doping concentrations of guests and the thickness of each functional layer, broad-spectrum white organic light-emitting diodes (WOLEDs) based on all-fluorescent materials with excellent color stability were realized.