Hu Jun, Wang Yinuo, Li Qiang, Shao Shiyang, Wang Lixiang, Jing Xiabin, Wang Fosong
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 China
School of Applied Chemistry and Engineering, University of Science and Technology of China Hefei Anhui 230026 China.
Chem Sci. 2021 Sep 3;12(39):13083-13091. doi: 10.1039/d1sc04389g. eCollection 2021 Oct 13.
Fluorescent polymers are suffering from low electroluminescence efficiency because triplet excitons formed by electrical excitation are wasted through nonradiative pathways. Here we demonstrate the design of hyperfluorescent polymers by employing through-space charge transfer (TSCT) polystyrenes as sensitizers for triplet exciton utilization and classic fluorescent chromophores as emitters for light emission. The TSCT polystyrene sensitizers not only have high reverse intersystem crossing rates for rapid conversion of triplet excitons into singlet ones, but also possess tunable emission bands to overlap the absorption spectra of fluorescent emitters with different bandgaps, allowing efficient energy transfer from the sensitizers to emitters. The resultant hyperfluorescent polymers exhibit full-color electroluminescence with peaks expanding from 466 to 640 nm, and maximum external quantum efficiencies of 10.3-19.2%, much higher than those of control fluorescent polymers (2.0-3.6%). These findings shed light on the potential of hyperfluorescent polymers in developing high-efficiency solution-processed organic light-emitting diodes and provide new insights to overcome the electroluminescence efficiency limitation for fluorescent polymers.
由于电激发形成的三线态激子通过非辐射途径被浪费，荧光聚合物的电致发光效率较低。在此，我们展示了通过使用空间电荷转移（TSCT）聚苯乙烯作为三线态激子利用的敏化剂，以及经典荧光发色团作为发光体来设计超荧光聚合物。TSCT聚苯乙烯敏化剂不仅具有高的反向系间窜越速率，可将三线态激子快速转化为单线态激子，而且具有可调谐的发射带，以与不同带隙的荧光发光体的吸收光谱重叠，从而实现从敏化剂到发光体的高效能量转移。所得的超荧光聚合物呈现全色电致发光，峰值从466纳米扩展到640纳米，最大外量子效率为10.3 - 19.2%，远高于对照荧光聚合物（2.0 - 3.6%）。这些发现揭示了超荧光聚合物在开发高效溶液处理有机发光二极管方面的潜力，并为克服荧光聚合物的电致发光效率限制提供了新的见解。
