Liang Xiao, Tu Zhen-Long, Zheng You-Xuan
State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China.
Chemistry. 2019 Apr 17;25(22):5623-5642. doi: 10.1002/chem.201805952. Epub 2019 Feb 19.
Thermally activated delayed fluorescence (TADF) is one of the most intriguing and promising discoveries towards realization of highly-efficient organic light emitting diodes (OLED) utilizing small molecules as emitters. It has the capability of manifesting all excitons generated during the electroluminescent processes, consequently achieving 100 % of internal quantum efficiency. Since the report of the first efficient OLED based on a TADF small molecule in 2012 by Adachi et al., the quest for optimal TADF materials for OLED application has never stopped. Various TADF molecules bearing different design concepts and strategies have been designed and produced, with the aim to boost the overall performances of corresponding OLEDs. In this minireview, the general principles of TADF molecular design based on three basic categories of TADF species: twisted intramolecular charge transfer (TICT), through-space charge transfer (TSCT) and multi-resonance induced TADF (MR-TADF) are discussed in detail. Several key aspects with respect to each category, as well as some effective methods to enhance the efficiency of TADF materials and corresponding OLEDs from the molecular engineering perspectives, are summarized and discussed to exhibit a general landscape of TADF molecular design to a wide variety of scientific researchers within this particular disciplinary area.
热激活延迟荧光（TADF）是实现以小分子为发光体的高效有机发光二极管（OLED）最引人关注且前景广阔的发现之一。它能够使电致发光过程中产生的所有激子都发光，从而实现100%的内量子效率。自2012年安达千波矢等人报道首个基于TADF小分子的高效OLED以来，寻找用于OLED应用的最佳TADF材料的工作从未停止。人们设计并合成了各种具有不同设计理念和策略的TADF分子，旨在提升相应OLED的整体性能。在这篇综述中，将详细讨论基于TADF物种的三个基本类别：扭曲分子内电荷转移（TICT）、空间电荷转移（TSCT）和多共振诱导TADF（MR-TADF）的TADF分子设计的一般原则。从分子工程的角度总结并讨论了每个类别的几个关键方面，以及一些提高TADF材料和相应OLED效率的有效方法，以便向该特定学科领域内的广大科研人员展示TADF分子设计的总体概况。
