Bridging Small Molecules to Conjugated Polymers: Efficient Thermally Activated Delayed Fluorescence with a Methyl-Substituted Phenylene Linker
Bridging Small Molecules to Conjugated Polymers: Efficient Thermally Activated Delayed Fluorescence with a Methyl-Substituted Phenylene Linker
复制标题
将小分子桥接至共轭聚合物：使用甲基取代的亚苯基连接体实现高效热激活延迟荧光
DOI：
10.1002/anie.201912556
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Wang Lixiang
中科院分区：
文献类型：
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作者：
Rao Jiancheng;Liu Xinrui;Li Xuefei;Yang Liuqing;Zhao Lei;Wang Shumeng;Ding Junqiao;Wang Lixiang
基于“TADF + Linker”策略（TADF=热激活延迟荧光），这里展示了允许高效延迟荧光的共轭聚合物的成功构建。小分子TADF嵌段使用甲基取代的亚苯基连接基连接在一起以形成聚合物。随着亚苯基上甲基数目的增加，来自离域聚合物主链的局部激发三重态（3LEb）的能级逐渐增加，并最终超过电荷转移三重态（3CT）。结果，对于含四甲基亚苯基的聚合物，可以恢复减弱的延迟荧光，显示出23.5%（68.8 cd A−1，60.0 lm W−1）的创纪录高的外量子效率（EQE）和（0.25，0.52）的国际照明委员会（CIE）坐标。 与橙子-红色TADF发射体组合，还获得了明亮的白色电致发光，峰值EQE为20.9%（61.1 cd A-1，56.4 lm W-1），CIE坐标为（0.36，0.51）。
Based on a “TADF + Linker” strategy (TADF=thermally activated delayed fluorescence), demonstrated here is the successful construction of conjugated polymers that allow highly efficient delayed fluorescence. Small molecular TADF blocks are linked together using a methyl‐substituted phenylene linker to form polymers. With the growing number of methyl groups on the phenylene, the energy level of the local excited triplet state (3LEb) from the delocalized polymer backbone gradually increases, and finally surpasses the charge‐transfer triplet state (3CT). As a result, the diminished delayed fluorescence can be recovered for the tetramethyl phenylene containing polymer, revealing a record‐high external quantum efficiency (EQE) of 23.5 % (68.8 cd A−1, 60.0 lm W−1) and Commission Internationale de l′Eclairage (CIE) coordinates of (0.25, 0.52). Combined with an orange‐red TADF emitter, a bright white electroluminescence is also obtained with a peak EQE of 20.9 % (61.1 cd A−1, 56.4 lm W−1) and CIE coordinates of (0.36, 0.51).