Wu Chao, Liu Weiqiang, Li Kai, Cheng Gang, Xiong Jinfan, Teng Teng, Che Chi-Ming, Yang Chuluo
College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China.
State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China.
Angew Chem Int Ed Engl. 2021 Feb 19;60(8):3994-3998. doi: 10.1002/anie.202013051. Epub 2020 Dec 27.
Intramolecular through-space charge-transfer (TSCT) excited states have been exploited for developing thermally activated delayed fluorescence (TADF) emitters, but the tuning of excited state dynamics by conformational engineering remains sparse. Designed here is a series of TSCT emitters with precisely controlled alignment of the donor and acceptor segments. With increasing intramolecular π-π interactions, the radiative decay rate of the lowest singlet excited state (S ) progressively increased together with a suppression of nonradiative decay, leading to significantly enhanced photoluminescence quantum yields of up to 0.99 in doped thin films. A high-efficiency electroluminescence device, with a maximum external quantum efficiency (EQE) of 23.96 %, was achieved and maintains >20 % at a brightness of 1000 cd m . This work sheds light on the importance of conformation control for achieving high-efficiency intramolecular exciplex emitters.
分子内空间电荷转移（TSCT）激发态已被用于开发热激活延迟荧光（TADF）发光体，但通过构象工程对激发态动力学进行调控的研究仍然较少。本文设计了一系列供体和受体片段排列精确可控的TSCT发光体。随着分子内π-π相互作用的增加，最低单重激发态（S）的辐射衰减速率逐渐增加，同时非辐射衰减受到抑制，导致掺杂薄膜中的光致发光量子产率显著提高，最高可达0.99。制备了一种高效电致发光器件，其最大外量子效率（EQE）为23.96%，在1000 cd m的亮度下保持>20%。这项工作揭示了构象控制对于实现高效分子内激基复合物发光体的重要性。
