具有分子间电荷转移效应的D-σ-A型热激活延迟荧光材料及其电致发光性能  

D-σ-A Type Thermally Activated Delayed Fluorescent Emitters with Intermolecular Charge Transition Effect and Its Electroluminescence Properties

作　　者：姚静锋 李昊泽 吴平 谢凤鸣 胡英元 赵鑫[1] YAO Jingfeng;LI Haoze;WU Ping;XIE Fengming;HU Yingyuan;ZHAO Xin(College of Chemistry and Life Sciences,Suzhou University of Science and Technology,Suzhou 215009,Jiangsu,China;Jiangsu Key Laboratory for Carbon-based Functional Materials&Devices,Institute of Functional Nano&Soft Materials(FUNSOM),Soochow University,Suzhou 215123,Jiangsu,China)

机构地区：[1]苏州科技大学化学与生命科学学院,江苏苏州215009 [2]苏州大学功能纳米与软物质研究院,江苏苏州215123

出　　处：《材料导报》2023年第14期224-231,共8页Materials Reports

基　　金：国家自然科学基金(21905048)。

摘　　要：设计合成了三种D-σ-A型热激活延迟荧光(TADF)材料2-(4-(9H-咔唑-9-基)苯氧基)蒽-9,10-二酮(AQOPCZ)、2-(4-(二苯氨基)苯氧基)蒽-9,10-二酮(AQOPDPA)和2-(4-(9,9-二甲基吖啶-10(9H)-基)苯氧基)蒽-9,10-二酮(AQOPDMAC)。这三种材料均采用C-Oσ键连接受体和供体,由于σ键阻断供体和受体之间的共轭,较好地实现了三种材料最高未占分子轨道(HOMO)和最低已占分子轨道(LUMO)轨道之间的分离,因此三种材料都获得了很小的三线态与单线态之间的能级差(ΔEST<0.1 eV)和显著的TADF特性。更重要的是,这三种材料与常见的TADF材料不同,它们几乎没有分子内电荷转换(intra-CT)效应,但都具有显著的分子间电荷转换(inter-CT)效应。由于这种强的inter-CT效应,三种TADF材料的荧光光谱在非掺杂薄膜中均显示出长波发射(580~652 nm),并且与溶液中的发射波长(552~574 nm)相比表现出显著的红移。基于这三种TADF材料的发光器件均表现出了较好的电致发光性能,其中,基于AQOPCZ的OLED展现出了最好的器件性能,其最大外量子效率(EQEmax)为6.07%,最大亮度为8 320 cd·m-2。本工作为长波TADF材料的设计、合成和研究提供了有益的参考。Three D-σ-A type thermally activated delayed fluorescent(TADF)materials,AQOPCZ,AQOPDPA and AQOPDMAC,were designed and synthesized using C-Oσbond connecting acceptor and donor.All of the materials possess tinyΔE ST(<0.1 eV),distinct TADF characteristics and limited overlap of the molecular frontier orbitals because of the C-Oσbond and the distorted molecular structure.Compared with common TADF materials,these materials hardly have intramolecular charge transition(intra-CT)effect,but own outstanding intermolecular charge transition(inter-CT)effect.Due to inter-CT effect,three materials show long-wavelength emission(580-652 nm)in non-doped film.The fluorescence spectra of three materials in non-doped film exhibit remarkable red-shift compared with that in the solution(552-574 nm).Among three devices based on these emitters,the device employing AQOPCZ achieved best performance with maximum external quantum efficiencies of 6.07%and maximum luminance of 8320 cd·m-2.This work enriched the kind of D-σ-A type TADF materials and the preparation methods of long-wavelength TADF materials.

关 键 词：有机发光二极管 热激活延迟荧光 分子间电荷转换 电致发光 

分 类 号：O621.22[理学—有机化学]