Article
Materials Science, Multidisciplinary
Yating Wen, Shengbing Xiao, Haichao Liu, Xuzhou Tian, Jianbo De, Tong Lu, Zhiqiang Yang, Deyue Zou, Ying Lv, Shi-Tong Zhang, Qing Su, Bing Yang
Summary: A new pure organic donor-acceptor molecule was designed and synthesized, demonstrating different luminescence characteristics in two crystal structures. The switchable luminescence between near ultraviolet delayed fluorescence and yellow room-temperature phosphorescence originates from a single-molecule conformational change involving the twist angle between donor and acceptor units. This work not only provides a new donor-acceptor architecture for pure organic multifunctional materials, but also suggests a novel strategy to design stimuli-responsive materials with unique luminescence switching by tuning the triplet state energy.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Wen-Jing Qin, Ji-Rui Zhang, Xu-Ke Tian, Xiao-Gang Yang, Yu-Ming Guo
Summary: A new strategy has been developed to achieve long-lived room temperature phosphorescence performance by forming a donor-acceptor structure in a coordination polymer, which features significantly higher lifetime (40.22 ms) than that of pristine phosphor.
Article
Chemistry, Physical
Kei Fukasawa, Yuma Sugawara, Rana Tsuru, Takashi Yamashita, Shuzo Hirata
Summary: This study observed enhanced red room-temperature phosphorescence based on a unique mechanism. The research found that disengagement of forbidden fluorescence from the excited singlet state, facilitated phosphorescence rate and high triplet yield contribute to the enhanced red phosphorescence.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Ling Zhou, Fan Ni, Nan Li, Kai Wang, Guohua Xie, Chuluo Yang
Summary: Purely organic emitters have great potential in near-infrared organic light-emitting diodes, but suffer from low efficiency. This contribution presents the design and synthesis of two pairs of thermally activated delayed fluorescence enantiomers with unique characteristics. The resulting OLEDs show high efficiency and near-infrared emission.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Applied
Ying Zeng, Xiangxiang Zhai, Guangming Wang, Yuming Su, Minjian Wu, Biaobing Wang, Kaka Zhang
Summary: Organic afterglow materials, featuring small rate constants of key photophysical processes, such as phosphorescence decay and nonradiative decay of triplet excited states, have become an important class of luminescent materials. The transformation of afterglow mechanism from room-temperature phosphorescence to thermally-activated delayed fluorescence in intramolecular charge transfer systems has been reported. This transformation is achieved by increasing the acceptor strength of the ICT molecules, reducing singlet-triplet splitting energy, and enabling reverse intersystem crossing pathway to harvest triplet energies. These findings provide deep understanding of the behaviors of organic triplets with small photophysical rate constants. In addition, these organic ICT molecules have shown promising applications when incorporated into aqueous emulsion systems.
Article
Chemistry, Applied
Oleg V. Borshchev, Maxim S. Skorotetcky, Vasily A. Trukhanov, Roman S. Fedorenko, Nikolay M. Surin, Evgeniya A. Svidchenko, Andrey Yu. Sosorev, Maxim S. Kazantsev, Dmitry Yu. Paraschuk, Sergei A. Ponomarenko
Summary: Two novel organic semiconductors were synthesized with TTA as the central core and end-capped with 5-hexyl-2-thiophene, (Hex-T)(2)-TTA, and 4-hexyl-phenyl, (Hex-Ph)(2)-TTA, for organic field effect transistor (OFET) applications. Characterization and studies were conducted on these TTA derivatives using various techniques and density functional theory calculations. Both TTA derivatives showed electroluminescence in OFETs, with (Hex-Ph)(2)-TTA exhibiting high hole mobility.
Article
Chemistry, Multidisciplinary
Giliandro Farias, Cristian A. M. Salla, Murat Aydemir, Ludmilla Sturm, Pierre Dechambenoit, Fabien Durola, Bernardo de Souza, Harald Bock, Andrew P. Monkman, Ivan H. Bechtold
Summary: Halogenation of a twisted three-fold symmetric hydrocarbon with F, Cl or Br leads to modulation of triplet-triplet annihilation and dual phosphorescence, with one being thermally activated and the other persistent and visible. The room temperature phosphorescence is highly unusual given the absence of lone-pair-contributing heteroatoms.
Article
Chemistry, Physical
Victoria M. Bjelland, Harue Nakashima, Naoaki Hashimoto, Satoshi Seo, Thor B. Melo, Mikael Lindgren
Summary: This study examines the molecular processes of triplet-triplet annihilation (TTA) in solvents at room temperature, with special focus on nonlinear kinetic reactions. Time- and spectrally resolved spectroscopy is used to simulate, measure, and fit the kinetic parameters of TET and TTA rate reactions without approximations. The study reveals that viscosity/diffusion and the excited triplet lifetime of the annihilator are crucial parameters for high TTA induced delayed fluorescence.
Article
Materials Science, Multidisciplinary
Tsutomu Ishi-i, Rihoko Kichise, In Seob Park, Takuma Yasuda, Taisuke Matsumoto
Summary: Room temperature red phosphorescence in organic dyes is achieved through aggregation-induced intersystem crossing and heavy-atom effect, resulting in the stabilization of excited triplet state and acceleration of phosphorescence radiation.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Zhu Wu, Fabian Dinkelbach, Florian Kerner, Alexandra Friedrich, Lei Ji, Vladimir Stepanenko, Frank Wuerthner, Christel M. Marian, Todd B. Marder
Summary: Designing highly efficient purely organic phosphors at room temperature is challenging due to fast non-radiative processes and slow intersystem crossing rates. This study successfully synthesized an isomer with dual phosphorescence and identified its emitting mechanism through theoretical calculations and crystal structure analysis.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Engineering, Environmental
Longjiang Xing, Ze-Lin Zhu, Jia He, Zhipeng Qiu, Zhiwen Yang, Dan Lin, Wen-Cheng Chen, Qingdan Yang, Shaomin Ji, Yanping Huo, Chun-Sing Lee
Summary: Three new anthracene-based emitters were developed for deep blue OLEDs, demonstrating highly twisted molecular configurations that lead to deep-blue light emission by restricting pi-conjugation extension. The molecular packing manner may influence photoluminescence quantum yields in solid state and the singlet exciton harvested by triplet-triplet annihilation process. A nondoped device using DPF-AnCN as emitter achieved an external quantum efficiency of 7.1% with insignificant efficiency roll-off, approaching standard blue index.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Materials Science, Multidisciplinary
Sheng-Yi Yang, Qi-Sheng Tian, Xiang-Ji Liao, Zheng-Guang Wu, Wan-Shan Shen, You-Jun Yu, Zi-Qi Feng, You-Xuan Zheng, Zuo-Quan Jiang, Liang-Sheng Liao
Summary: This study presents the first ever circularly polarized thermally activated delayed fluorescence molecule with a carbonyl-/sulfone-bridged triarylamine structure. Circularly polarized light emission is achieved through intramolecular steric hindrance and intramolecular space charge transfer. The molecule exhibits good quantum yield and clear circularly polarized luminescence in solution.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Materials Science, Multidisciplinary
Alessandro Landi, Daniele Padula
Summary: This article introduces a rigorous mathematical protocol borrowed from the field of multiobjective optimization to systematically identify the best compromise among all the properties relevant to thermally activated delayed fluorescence (TADF) applications. Through computational analysis of two typical TADF emitters, the conformations that optimize all parameters simultaneously are found, and structural modifications are proposed to constrain the dyes in their optimal conformations.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Nanoscience & Nanotechnology
Xun Li, Guangming Wang, Jiuyang Li, Yan Sun, Xinjian Deng, Kaka Zhang
Summary: In this study, intense dopant-matrix afterglow systems have been reported with high afterglow efficiency and afterglow lifetime. Through the use of hydrogen bonding and deuteration techniques, the rate of reverse intersystem crossing of the dopant triplets is reduced, resulting in unexpectedly high afterglow brightness and duration even at room temperature. Triplet-triplet annihilation has also been observed at high doping concentrations to further enhance the afterglow efficiency.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Review
Chemistry, Multidisciplinary
Zhenhong Qi, Bo Zhou, Dongpeng Yan
Summary: This review systematically summarizes the recent developments in metal-organic halide (MOH) materials, including their self-assembled modes, design strategies, and potential applications. It aims to promote the research on MOHs for novel optical and photofunctional applications.
MATERIALS CHEMISTRY FRONTIERS
(2023)