Review
Chemistry, Multidisciplinary
Lucas Frederic, Alaric Desmarchelier, Ludovic Favereau, Gregory Pieters
Summary: The development of efficient CP-Organic Light-Emitting Diodes (CP-OLEDs) through the design of fluorophores merging circularly polarized (CP) luminescence and thermally activated delayed fluorescence (TADF) properties is a promising direction. This progress report provides an overview of molecular designs explored to obtain CP-TADF properties, their performance as chiral emitters in CP-OLEDs, and the future challenges in this emerging research field.
ADVANCED FUNCTIONAL MATERIALS
(2021)
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, Multidisciplinary
Shulei Liu, Songsong Liu, Yang Gao, Hao Lan, Lili Lin, Chuan-Kui Wang, Jianzhong Fan, Yuzhi Song
Summary: The effects of different acceptors on circularly polarized luminescence (CPL) and TADF properties are investigated, revealing the inner mechanisms between basic molecular structures and luminescence properties. The study concludes that lengthening the acceptor unit is a feasible strategy for improving the luminescence properties of CP-TADF molecules. This research provides a novel approach for understanding the molecular luminescence mechanism of CP-TADF and promoting the development of CP-OLEDs.
MATERIALS TODAY CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Hai-Jie Wang, Yuan Liu, Baoqiu Yu, Shi-Quan Song, You-Xuan Zheng, Kanglei Liu, Pangkuan Chen, Hailong Wang, Jianzhuang Jiang, Tian-Yi Li
Summary: We successfully tuned the configuration of linear two-coordinate coinage metal complexes from coplanar to orthogonal by varying the substituents, and found that the thermally activated delayed fluorescence (TADF) is sensitive to the geometric arrangement of the ligands. The complex with confined twist configuration exhibited outstanding luminescent properties with a high phi(PL) of 0.74 and a short tau(TADF) of 1.9 mu s, indicating fast enough k(r,TADF) of 3.9x10(5) s(-1) and depressed k(nr) of 1.4x10(5) s(-1). Vacuum-deposited blue OLEDs with either doped or host-free emissive layer showed external quantum efficiencies over 20% and 10% respectively, demonstrating the practicality of the configurationally confined strategy for efficient linear Cu-I TADF emitters.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Yincai Xu, Qingyang Wang, Xinliang Cai, Chenglong Li, Yue Wang
Summary: In this study, highly efficient organic light-emitting diodes that exhibit pure green emission and circularly polarized electroluminescence signal were developed by integrating circularly polarized luminescence and thermally activated delayed fluorescence emission induced by multiple resonance effect. This represents a significant advancement in the field of organic electronics.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Hui Wang, Kai Wang, Jia-Xiong Chen, Xi Zhang, Lu Zhou, Xiao-Chun Fan, Ying-Chun Cheng, Xiao-Yao Hao, Jia Yu, Xiao-Hong Zhang
Summary: To achieve deep-red/near-infrared emission in organic light-emitting diodes (OLEDs), intermolecular interactions of red emitters are usually required, but these interactions often lead to efficiency declines. In this study, an advanced method of managing intermolecular interactions of thermally activated delayed fluorescence (TADF) emitters was proposed. This work provides instructive guidance for manipulating the intermolecular interactions of red TADF emitters and will contribute to the development of high-performance DR/NIR OLEDs in the future.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Wenbo Ma, Yirong Su, Qisheng Zhang, Chao Deng, Luca Pasquali, Wenjuan Zhu, Yue Tian, Peng Ran, Zeng Chen, Gaoyuan Yang, Guijie Liang, Tianyu Liu, Haiming Zhu, Peng Huang, Haizheng Zhong, Kangwei Wang, Shaoqian Peng, Jianlong Xia, Huafeng Liu, Xu Liu, Yang (Michael) Yang
Summary: X-ray detection relies on inorganic scintillators, but using thermally activated delayed fluorescence molecules as scintillators can significantly increase efficiency and imaging quality, showing the importance of efficient harvesting of triplet excitons under X-ray excitation.
Article
Chemistry, Multidisciplinary
Xiang-Ji Liao, Dongdong Pu, Li Yuan, Jingjing Tong, Shuai Xing, Zhen-Long Tu, Jing-Lin Zuo, Wen-Hua Zheng, You-Xuan Zheng
Summary: Chiral boron/nitrogen doped multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters based on planar chiral paracyclophane exhibit high photoluminescence quantum yields and symmetric circularly polarized photoluminescence spectra in doped films. The sky-blue CP-OLEDs with (R/S)-Czp-tBuCzB show high external quantum efficiency and narrowest full-width at half-maximum among reported CP-OLEDs, while the devices with (R/S)-Czp-POAB display nearly pure green CP electroluminescence. These findings demonstrate the reliable strategy of incorporating planar chirality into MR-TADF emitters for efficient CP-OLEDs construction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Qingyang Wang, Li Yuan, Cheng Qu, Tingting Huang, Xiaoxian Song, Yincai Xu, You-Xuan Zheng, Yue Wang
Summary: This study develops a pair of high-performance circularly polarized multiple-resonance thermally activated delayed fluorescence enantiomers, which can be fabricated into highly efficient circularly polarized organic light-emitting diodes. The optimized devices exhibit pure green emission, high external quantum efficiency, and clear circularly polarized electroluminescence signals.
ADVANCED MATERIALS
(2023)
Article
Engineering, Environmental
Simin Jiang, Jianyin Lin, Deli Li, Mengke Li, Yanmei He, Wentao Xie, Jiting Chen, Yiyang Gan, Guo-Xi Yang, Zhihai Yang, Wei Li, Shi-Jian Su
Summary: Intramolecular charge transfer (intra-CT) and intermolecular charge transfer (inter-CT) are two general molecular design strategies for thermally activated delayed fluorescence (TADF) materials. By tuning the doping concentrations, the influence of molecular conjugation on charge transfer can be overcome. The planar molecular skeleton enhances intramolecular electronic coupling, reduces steric hindrance, and shortens intermolecular distance, leading to improved charge transfer efficiency.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
Jibiao Jin, Wuji Wang, Peiran Xue, Qingqing Yang, He Jiang, Ye Tao, Chao Zheng, Guohua Xie, Wei Huang, Runfeng Chen
Summary: The study introduces an intermolecular locking strategy to enhance both the solution processibility and photoluminescence efficiency of red TADF emitters, resulting in excellent device performance in solution-processed TADF OLEDs.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Giulio Pavan, Luca Morgan, Nicola Demitri, Chiara Alberoni, Thomas Scattolin, Alessandro Aliprandi
Summary: A family of novel thermally activated delayed fluorescence (TADF) emitters was synthesized by a simple and metal-free method, and their structures were characterized. The photophysical and electrochemical properties of different donors were systematically tested and correlated with their performance in electrochemiluminescence using benzoyl peroxide as a co-reactant or in annihilation conditions. Efficiency in electrochemiluminescence was mainly determined by the electrochemical reversibility of the redox processes rather than the photophysical properties, and the annihilation efficiency strongly depended on the pulse sequence. The alkylated imidazole moiety allowed for the insertion of functional groups, enabling practical applications.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Engineering, Environmental
Xuepu Wang, Junbo Li, Ying Zeng, Xiuzheng Chen, Minjian Wu, Guangming Wang, Xun Li, Biaobing Wang, Kaka Zhang
Summary: We report on dopant-matrix materials that achieve high afterglow efficiency of 92.4 +/- 10.7% and long afterglow duration up to 1 hour under ambient conditions. These materials utilize thermally activated delayed fluorescence (TADF) mechanism at room temperature to harvest triplet energies and exhibit near unity afterglow efficiency. At high excitation doses, the materials follow a power law decay of excited states due to retarded charge recombination, resulting in an hour-long afterglow duration. The combination of TADF mechanism and two-photon ionization provides a new strategy to address the efficiency-to-duration conflict in afterglow systems.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Shuai Li, Jingyao Chen, Yuling Wei, Jianbo De, Hua Geng, Qing Liao, Runfeng Chen, Hongbing Fu
Summary: This study demonstrates the fabrication of organic microwire lasers with high optical gain and high PLQY by combining AIE and LE characteristics in TADF emitters, providing new insights for designing TADF materials for OSSLs.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Zhen Chen, Daoyuan Zheng, Ruiling Zhang, Haiwen Wei, Xin Mao, Feng Liu, Keli Han
Summary: In this study, a novel electron donor-acceptor binary system was designed and investigated for its outstanding organic long-persistent luminescence (OLPL) performance. The binary system exhibited effective OLPL emission that lasted for more than 100 s after 1 min of ultraviolet light irradiation at room temperature. It also showed temperature-sensitive thermally activated delayed fluorescence emission and the formation of a charge-separated state.
Article
Engineering, Environmental
Simin Jiang, Jianyin Lin, Deli Li, Mengke Li, Yanmei He, Wentao Xie, Jiting Chen, Yiyang Gan, Guo-Xi Yang, Zhihai Yang, Wei Li, Shi-Jian Su
Summary: Intramolecular charge transfer (intra-CT) and intermolecular charge transfer (inter-CT) are two general molecular design strategies for thermally activated delayed fluorescence (TADF) materials. By tuning the doping concentrations, the influence of molecular conjugation on charge transfer can be overcome. The planar molecular skeleton enhances intramolecular electronic coupling, reduces steric hindrance, and shortens intermolecular distance, leading to improved charge transfer efficiency.
CHEMICAL ENGINEERING JOURNAL
(2023)