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具有高效热激活延迟荧光的立体锁定给体-受体共轭聚合物
作者:小柯机器人 发布时间:2021/2/10 14:29:51

云南大学丁军桥团队首次开发了具有高效热激活延迟荧光的立体锁定给体-受体共轭聚合物。 相关研究成果发表在2021年2月05日出版的《德国应用化学》。

基于施主-受主(D-A)结构,热激活延迟荧光(TADF)小分子被广泛应用于高性价比和高性能的有机发光二极管(OLED)。然而,作为一种类似物,由于共轭延伸到一定程度,D‐A共轭聚合物往往具有显著的前线分子轨道重叠,导致不存在由大的单重态-三重态能量分裂(EST)引起的TADF。

为了解决这一问题,该文提出了一种新的空间锁定策略,将甲基引入D-A共轭聚合物中。得益于甲基的阻碍,施主和受主之间的扭转可以很好地调节以形成空间锁定的构象,从而不必要的向平面方向的弛豫以及共轭延伸被阻止,从而促进空穴-电子分离。因此,合成的立体锁定D‐A共轭聚合物实现了0.09 eV的极低E ST,以实现高效的TADF。

通过溶液工艺制备相应的掺杂和非掺杂器件,显示出分别为24.0%(79.4 cd/A,75.0 lm/W)和15.3%(50.9 cd/A,47.3 lm/W)的创纪录的高外部量子效率(EQE),以及在高亮度下的温和效率衰减。

附:英文原文

Title: Sterically‐Locked Donor‐Acceptor Conjugated Polymers Showing Efficient Thermally Activated Delayed Fluorescence

Author: Junqiao Ding, Jiancheng Rao, Liuqing Yang, Xue Li, Lei Zhao, Shumeng Wang, Hongkun Tian, Lixiang Wang

Issue&Volume: 05 February 2021

Abstract: Based on a donor‐acceptor (D‐A) structure, small molecules with thermally activated delayed fluorescence (TADF) have been widely applied in cost‐effective and high‐performance organic light‐emitting diodes (OLEDs). As an analogue, however, D‐A conjugated polymers often possess a significant frontier molecular orbital overlap because of the conjugation elongation to some degree, leading to no TADF caused by a large singlet‐triplet energy splitting ( E  ST  ). To solve this problem, herein a novel steric locking strategy is proposed by incorporating methyl groups into D‐A conjugated polymers. Benefitting from the methyl hindrance, the torsion between the donor and acceptor can be well tuned to form a sterically‐locked conformation, so that the unwanted relaxation toward planarity and thus conjugation elongation is prevented to boost hole‐electron separation. Consequently, the resultant sterically‐locked D‐A conjugated polymer achieves an extremely low E  ST  of 0.09 eV to enable efficient TADF. The corresponding doped and non‐doped devices are fabricated via a solution process, revealing a record‐high external quantum efficiency (EQE) of 24.0% (79.4 cd/A, 75.0 lm/W) and 15.3% (50.9 cd/A, 47.3 lm/W), respectively, together with a gentle efficiency roll‐off at high luminance.

DOI: 10.1002/anie.202016428

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202016428

期刊信息

Angewandte Chemie:《德国应用化学》,创刊于1887年。隶属于德国化学会,最新IF:12.959
官方网址:https://onlinelibrary.wiley.com/journal/15213773
投稿链接:https://www.editorialmanager.com/anie/default.aspx