Article
Chemistry, Multidisciplinary
Chengcheng Wu, Kai-Ning Tong, Kefei Shi, Zhaoyun Jin, Yuan Wu, Yingxiao Mu, Yanping Huo, Man-Chung Tang, Chen Yang, Hong Meng, Feiyu Kang, Guodan Wei
Summary: By introducing bulky trimethylsilyl (TMS) groups, two newly designed and synthesized [3+2+1] iridium complexes, doped with a terminal emitter of v-DABNA, exhibit coincident overlapping spectra between the emission of these two phosphors and the absorption of v-DABNA, enabling efficient triplet harvesting through cascade resonant energy transfer. The optimized hyper-OLEDs achieve a high external quantum efficiency of 31.06%, pure blue emission peak at 467 nm with narrow full width at half maxima (FWHM) of 18 nm, and a CIEy value of 0.097, meeting the requirements for saturated blue OLEDs display set by the National Institute of Standards and Technology (NIST). Furthermore, the hyper-OLEDs demonstrate an impressive converted lifetime (LT50) of up to 4552 h at a brightness of 100 cd m(-2), indicating effective Förster resonance energy transfer (FRET) process. These results highlight the potential of employing bulky TMS substituent [3+2+1] iridium(III) complexes as effective sensitizers for the development of high efficiency and stable blue OLEDs in display and lighting applications.
Article
Chemistry, Inorganic & Nuclear
Sergej Stipurin, Thomas Strassner
Summary: The combination of strong electron-withdrawing groups in cyclometalated N-heterocyclic carbene ligands with known beneficial auxiliary ligands in phosphorescent platinum(II) complexes results in efficient light-to-deep-blue emission with quantum yields of up to 92%. The compounds were characterized and studied for their photophysical, electrochemical, and thermal properties, with three complexes being characterized by solid-state structures. Density functional theory calculations were performed using PBE0/6-311G* with dispersion correction.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Sunwoo Kang, Taekyung Kim, Jin Yong Lee
Summary: A series of Ir- and Pt-based blue phosphorescent materials were theoretically investigated using DFT calculations to improve their chemical stability in the excited state. Introducing intra- and inter-ligand interactions in Ir and Pt complexes significantly increased the Delta E((MC)-M-3-T-1) to prevent decomposition reactions, resulting in the highest reported values to date. The research provides insights into improving device lifetimes by enhancing the excited state chemical stability of deep blue phosphorescent materials.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Hea Jung Park, Jee-Hun Jang, Jeong-Hwan Lee, Do-Hoon Hwang
Summary: In this study, a bulky trimethylsilyl (TMS)-substituted blue phosphorescent Pt(II) complex (PtON7-TMS) is successfully synthesized to improve color purity, and it maintains a pure blue color even at high doping concentrations.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Peng Tao, Xiao-Kang Zheng, Xiao-Zhen Wei, Mei-Tung Lau, Yuk-Ki Lee, Zi-Kang Li, Ze-Ling Guo, Fang-Qing Zhao, Xing Liu, Shu-Juan Liu, Qiang Zhao, Yan-Qin Miao, Wai-Yeung Wong
Summary: Three efficient yellow iridium(III) complexes were designed using a chlorine-functionalization method, exhibiting extremely broad emission bandwidths and bright yellow phosphorescence in N-2-saturated dichloromethane with high photoluminescence efficiency. These complexes show great potentials in developing high-performance yellow and white electroluminescence, with high external quantum efficiency realized in the prepared OLEDs.
MATERIALS TODAY ENERGY
(2021)
Article
Chemistry, Multidisciplinary
Zijian Liu, Si-Wei Zhang, Meng Zhang, Chengcheng Wu, Wansi Li, Yuan Wu, Chen Yang, Feiyu Kang, Hong Meng, Guodan Wei
Summary: The successful synthesis of the novel iridium (III) complex Ir-dfpMepy-CN has opened a new pathway for developing advanced blue emitters and dopant alternatives for future efficient blue PhOLEDs, exhibiting high quantum efficiency and deeper blue emission.
FRONTIERS IN CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Yongjun Song, Renyou Yu, Mengzhen Chen, Lei He
Summary: This study reports the development of fluorine-free cyan to deep blue emissive cationic Ir(III) complexes with phenylimidazole-type cyclometalated ligands, showing good emission properties in both solution and diluted films, as well as promising applications in OLEDs and solid-state LEECs.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Shiro Koseki, Masaki Yoshii, Toshio Asada, Yuichi Fujimura, Takeshi Matsushita, Shigeyuki Yagi
Summary: Theoretical calculations were conducted to determine the best candidate for a blue-color phosphorescent complex among several derivatives of bis(2-phenylpyridine)(acetylacetonate)iridium(III). Results showed that the introduction of F and/or CN substituents in certain positions of the ligands causes a blue shift of emission spectra, with Ir(5CN,6-F-ppy)2(acac) being identified as a promising candidate due to its calculated rate constants for S1 -Aa T1 and moderate emission intensity.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Materials Science, Multidisciplinary
Bo-Sun Yun, So-Yoen Kim, Jin-Hyoung Kim, Ho-Jin Son, Sang Ook Kang
Summary: In this study, NHC-Ir complexes utilizing DBT and DBF moieties to enhance deep-blue phosphorescence emission efficiency were synthesized and compared for their electrochemical and photophysical properties. The use of DBT moieties resulted in longer emission wavelengths, while the meridional isomer exhibited easier oxidation and red-shifted emission compared to facial forms. The replacement of the oxygen atom in the DBF unit with sulfur did not significantly alter the emission efficiency, achieving high-end deep-blue phosphorescence with unprecedented CIE coordinates.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Optics
Jinwon Sun, Heechoon Ahn, Sunwoo Kang, Soo-Byung Ko, Dayoon Song, Hyun Ah Um, Sungbum Kim, Yoonkyoo Lee, Pyungeun Jeon, Seok-Hwan Hwang, Youngmin You, Changwoong Chu, Sunghan Kim
Summary: By using new dopant and host materials, a deep blue phosphorescent organic light-emitting diode with a lifetime exceeding 1,000 hours has been successfully produced. The application of these materials results in longer device lifetimes and higher color purity.
Article
Chemistry, Physical
Z. -L. Zhu, L. -Y. Hsu, W. -S. Tai, S. -F. Ni, C. -S. Lee, Y. Chi
Summary: Novel bis-tridentate Ir(III) complexes with 6-(1,2,4-triazolyl)-2-phenoxypyridine (tazPx) as chromophoric chelates show improved photostabilities and competitive performances in blue-emitting organic light-emitting diodes, with high quantum yields and shortened radiative lifetime compared to complexes using other chelates. Theoretical calculations reveal the significant contribution of the triazolate moiety to the radiative transition, leading to enhanced performance of the tazPx-based complex.
MATERIALS TODAY ENERGY
(2021)
Article
Nanoscience & Nanotechnology
Yumeng Chen, Chunyue Qian, Ke Qin, Hongbo Li, Xiaobo Shi, Zhenzhong Lu, Huili Ma, Tianshi Qin, Xiao-Chun Hang, Wei Huang
Summary: The stable complex Pt(mpzpyOczpy-mesi) described here embodies efficient, narrow blue emission due to its highly twisted structure that reduces intermolecular interactions. This complex shows high photoluminescence efficiency (>95%) in solution and a narrow emission spectrum, enhancing the stability and efficiency of photo- and electroluminescence. The top-emitting phosphorescent devices TE1, TE2, and TE4 achieve ultrapure blue color with high brightness and efficiency, demonstrating almost negligible color deviation at various viewing angles.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Chengcheng Wu, Min Wang, Kai-Ning Tong, Meng Zhang, Wansi Li, Zhuhua Xu, Wei-Long Zhang, Yuan Wu, Chen Yang, Hong-Yan Fu, Season Si Chen, Maggie Ng, Man-Chung Tang, Guodan Wei
Summary: A family of six coordinated 2-(2 ',4 '-difluorophenyl) pyridine-based Iridium(III) complexes with intermolecular interactions were designed to improve their emission properties. These complexes were successfully applied to blue phosphorescent organic light-emitting diodes (OLEDs), demonstrating excellent performance.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Campbell F. R. Mackenzie, Le Zhang, David B. Cordes, Alexandra M. Z. Slawin, Ifor D. W. Samuel, Eli Zysman-Colman
Summary: The synthesis of four new deep-blue-emitting iridium(III) NHC complexes with sterically demanding ligands shows promising results for application in organic light-emitting diodes.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Multidisciplinary Sciences
Zhen Zhang, Dehai Dou, Rongrong Xia, Peng Wu, Eduard Spuling, Ke Wang, Jin Cao, Bin Wei, Xifeng Li, Jianhua Zhang, Stefan Braese, Zixing Wang
Summary: In this study, a novel molecule was designed to achieve highly efficient and stable blue organic light-emitting diodes (OLEDs), resulting in deep-blue emission with high external quantum efficiency at high luminance through fast and efficient reverse intersystem crossing.
Article
Chemistry, Multidisciplinary
Ze-Lin Zhu, Sheng-Fu Wang, Li-Wen Fu, Ji-Hua Tan, Chen Cao, Yi Yuan, Shek-Man Yiu, Ye-Xin Zhang, Yun Chi, Chun-Sing Lee
Summary: By fusing the pyrazinyl pyrazole entity to form a pyrazolo[3,4-f]quinoxaline chelate, the Os(II) based NIR emitter exhibits efficient electroluminescence with a peak at 811 nm, a maximum external quantum efficiency of 0.97%, and a suppression of efficiency roll-off up to a current density of 300 mA cm(-2).
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Fang Fang, Yi Yuan, Yingpeng Wan, Jing Li, Yueyue Song, Wen-Cheng Chen, Dongxu Zhao, Yun Chi, Menglin Li, Chun-Sing Lee, Jinfeng Zhang
Summary: Thermally activated delayed fluorescence (TADF) materials with extremely small singlet-triplet energy offsets have shown potential for the development of metal-free photosensitizers. This study designs TADF nanoparticles as purely organic photosensitizers, which demonstrate promising potential in two-photon-excited (TPE) photodynamic therapy (PDT) and near-infrared imaging.
Review
Chemistry, Multidisciplinary
Yu-Chen Wei, Kai-Hua Kuo, Yun Chi, Pi-Tai Chou
Summary: Designing bright and efficient near-infrared (NIR) emitters has become a hot research topic in the fields of biological imaging, medical therapy, optical communication, and night-vision devices. Two complementary approaches, exciton delocalization and molecular deuteration, have been proposed to suppress nonradiative internal conversion rates and increase the efficiency of NIR emission. This concept has been experimentally verified using square-planar Pt(II) complexes. The results show high NIR emission efficiency and photoluminescent quantum yield.
ACCOUNTS OF CHEMICAL RESEARCH
(2023)
Article
Nanoscience & Nanotechnology
Jie Yan, Sheng Fu Wang, Chao-Hsien Hsu, Emily Hsue-Chi Shi, Chi-Chi Wu, Pi-Tai Chou, Shek-Man Yiu, Yun Chi, Caifa You, I-Che Peng, Wen-Yi Hung
Summary: In this study, we synthesized different blue emitting homoleptic iridium(III) phosphors with specific cyclometalates. These iridium complexes displayed intense phosphorescence in the solution state and were able to transfer energy to multiresonance thermally activated delayed fluorescence (MR-TADF) terminal emitters via Fo''rster resonance energy transfer (FRET). OLEDs using these phosphors achieved true blue, narrow bandwidth emission with high efficiency. The research also analyzed the kinetic parameters involved in energy transfer processes and proposed ways to improve efficiency roll-off.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Yu-Chen Wei, Bo-Han Chen, Ren-Siang Ye, Hsing-Wei Huang, Jia-Xuan Su, Chao-Yang Lin, Justin Hodgkiss, Lian-Yan Hsu, Yun Chi, Kai Chen, Chih-Hsuan Lu, Shang-Da Yang, Pi-Tai Chou
Summary: Based on transient absorption spectroscopy and transient grating photoluminescence spectroscopy, this study reveals the collective out-of-plane motions of the aggregated Pt-II complex 4H in excited states, which facilitate the excited-state deactivation and enhance the near-infrared emission efficiency.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Nanoscience & Nanotechnology
Jin-Tin Lin, Chia-Sheng Huang, Cheng Ming Hui, Yu-Hong Liang, Luke The, Fang-Hsien Lu, Yun Chi, Sheng-Fu Wang, K. R. Justin Thomas, Jwo-Huei Jou
Summary: Nanoparticles can enhance the performance of optoelectronic devices, but their limited absorption bandwidth at around 520 nm restricts their effectiveness in the red region. However, this study demonstrates that a single nanoparticle based on nonprecious copper can significantly enhance the efficiency of LEDs of all colors, with an unprecedented wide absorption band.
ACS APPLIED NANO MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Jie Yan, Zi-Qi Feng, Yixin Wu, Dong-Ying Zhou, Shek-Man Yiu, Chin-Yiu Chan, Yi Pan, Kai Chung Lau, Liang-Sheng Liao, Yun Chi
Summary: Efficient blue phosphors for OLEDs remain challenging. Researchers have synthesized a series of Ir(III) complexes and studied their structures and photophysical properties to overcome this challenge. Some of the emitters can undergo interconversion without decomposition in a specific solvent. The synthesized Ir(III) complexes exhibit good luminescence properties and show potential for making blue OLEDs.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Inorganic & Nuclear
Jie Yan, Min Song, Dong-Ying Zhou, Shek-Man Yiu, Liang-Sheng Liao, Yun Chi, Mo Xie
Summary: Homoleptic charge-neutral Ir(III) metal complexes with tridentate chelates composed of pyrazole-pyridine-pyrazolefragments were synthesized, and the substituents on the chelate played a significant role in tuning their photophysical and electrochemical properties. By introducing CF3 substituents at specific positions, the phosphorescence color of the complexes could be adjusted from green to orange with improved emission quantum yield. The newly synthesized Ir(III) complexes showed high thermal stability and were applied as dopant emitters in OLEDs, exhibiting high external quantum efficiency and current efficiency.
Article
Multidisciplinary Sciences
Jie Yan, Dong-Ying Zhou, Liang-Sheng Liao, Martin Kuhn, Xiuwen Zhou, Shek-Man Yiu, Yun Chi
Summary: In this study, four Ir(III) metal complexes were designed to achieve efficient blue emission through efficient energy transfer. The complexes also underwent isomerization in the presence of catalysts, allowing for mass production. The resulting hyper-OLED displayed true-blue color and high external quantum efficiency, paving the way for innovative blue OLED technology.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Jie Yan, Min Song, Dong-Ying Zhou, Guowei Ni, Muhua Gu, Shek-Man Yiu, Xiuwen Zhou, Liang-Sheng Liao, Yun Chi
Summary: Efficient saturated red and near-infrared emissive bis-tridentate Ir(III) complexes have been synthesized for the development of organic light-emitting diodes (OLEDs). The resulting OLED devices demonstrate high external quantum efficiencies and emission peak wavelengths.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Jie Yan, Yixin Wu, I-Che Peng, Yi Pan, Shek-Man Yiu, Ken-Tsung Wong, Wen-Yi Hung, Yun Chi, Kai-Chung Lau
Summary: In this study, three Ir(iii) based carbene complexes were synthesized and characterized. These complexes exhibited sky-blue emission and high photoluminescent quantum yields. One of the complexes showed high efficiency and external quantum efficiency in blue OLED devices.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Ze-Lin Zhu, Jie Yan, Li-Wen Fu, Chen Cao, Ji-Hua Tan, Sheng-Fu Wang, Yun Chi, Chun-Sing Lee
Summary: By modifying Pt(ii) dicarbene pincer complexes, the effect of aromatic substituents on excimer formation was studied. IPrtBuPt showed high stability and ultrahigh luminous efficiency, maintaining blue emission at doping concentrations of up to 20%. Furthermore, the emission of IPrtBuPt significantly overlapped with the absorption of nu-DABNA, achieving high EQEs, narrow FWHM, and specific CIE coordinates in a hyper-OLED structure.
MATERIALS CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Inorganic & Nuclear
Guowei Ni, Jie Yan, Yixin Wu, Fan Zhou, Pi-Tai Chou, Yun Chi
Summary: Third-row transition-metal complexes are crucial in the production of light-emitting layers for OLED technology. It is essential to extend their emission wavelengths to true-blue and near-infrared regions to enhance the performance and enable new applications. This chemistry frontier article elaborates on using transition metals like iridium and platinum and carefully designed chelates to assemble advanced emitters.
INORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Nanoscience & Nanotechnology
Eun Hae Cho, Hye-Ryung Choi, Yongjin Park, So Yeong Jeong, Young Jin Song, Yong Ha Hwang, Junwoo Lee, Yun Chi, Sheng-Fu Wang, Yongmin Jeon, Chang-Hun Huh, Kyung Cheol Choi
Summary: This study focuses on wearable and wavelength-tunable near-infrared organic light-emitting diodes (NIR OLEDs) that use a silver electrode instead of the traditional indium tin oxide (ITO) electrode. The NIR OLEDs show stable operation and wavelength tuning capabilities, and have a promoting effect on cell proliferation under NIR light irradiation, indicating their potential for efficacious phototherapy.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Jibiao Jin, Zelin Zhu, Jie Yan, Xiuwen Zhou, Chen Cao, Pi-Tai Chou, Ye-Xin Zhang, Zhong Zheng, Chun-Sing Lee, Yun Chi
Summary: In this research, a series of blue-emitting Ir(III) phosphors based on cyclometalating N-heterocyclic carbenes (NHCs) were reported. Experimental and theoretical characterization showed that these emitters have high photoluminescence quantum yields, short radiative lifetimes, and excellent photophysical characteristics. Furthermore, high-efficiency blue and true-blue hyperphosphorescent OLEDs were successfully achieved by utilizing these phosphors.
ADVANCED PHOTONICS RESEARCH
(2022)
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)
