High-Efficiency, Non-doped, Pure-Blue Fluorescent Organic Light-Emitting Diodes via Molecular Tuning Regulation of Hot Exciton Excited States
High-Efficiency, Non-doped, Pure-Blue Fluorescent Organic Light-Emitting Diodes via Molecular Tuning Regulation of Hot Exciton Excited States
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通过热激子激发态的分子调谐调节高效、无掺杂、纯蓝色荧光有机发光二极管
DOI：
10.1021/acsami.0c15876
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Wenjun Yang
中科院分区：
文献类型：
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作者：
Xianhao Lv;Lei Xu;Wei Cui;Yuan Yu;Huayi Zhou;Miao Cang;Qikun Sun;Yuyu Pan;Yuwei Xu;Dehua Hu;Shanfeng Xue;Wenjun Yang
为了通过利用三重态激子从最低三重态激发态（T1）到最低单重态激发态（S1）的转换来实现高效率的蓝色有机发光二极管（OLED），已经在研究三重态-三重态湮灭（TTA）和热激活延迟荧光（TADF）材料方面进行了巨大的努力。然而，从上三重态能级状态（Tn，n> 1）到最低单重态激发态（S1）的热激子转换是用于实现具有与TTA和TADF材料的性能相当的性能的纯蓝色非掺杂OLED的越来越有前途的方法。本文设计并合成了两种供体（D）-π-受体（A）型纯蓝色荧光发射体PIAnCz和PIAnPO。理论计算和电子物理实验证实了PIAnCz和PIAnPO的激发态特性，证明了这两种材料的热激子性质。基于PIAnCz和PIAnPO作为发射层材料，所制备的非掺杂器件表现出纯蓝色发射，其国际照明委员会（CIE）坐标为（0.16，0.12）和（0.16，0.15），最大发光强度为10，484和15，485 cd m-2，最大外量子效率（EQE）为10.9%和8.3%。此外，在1000 cd m-2的发光下，基于PIAnPO的器件的EQE仍然可以高达7.7%，并且可以忽略的效率滚降为6.0%。两种材料的器械性能证明了其商业应用的出色潜力。
Tremendous efforts have been made on researching triplet–triplet annihilation (TTA) and thermally activated delayed fluorescence (TADF) materials for realizing high-efficiency blue organic light-emitting diodes (OLEDs) through utilizing triplet exciton conversion to the lowest singlet excited state (S1) from the lowest triplet excited state (T1). However, hot exciton conversion from the upper triplet energy level state (Tn,n> 1) to the lowest singlet excited state (S1) is an increasingly promising method for realizing pure-blue non-doped OLEDs with performances comparable to those of TTA and TADF materials. Herein, two pure-blue fluorescent emitters of donor (D)−π–acceptor (A) type, PIAnCz and PIAnPO, were designed and synthesized. The excited-state characteristics of PIAnCz and PIAnPO, confirmed by theoretical calculations and photophysical experiments, demonstrated these materials’ hot exciton properties. Based on PIAnCz and PIAnPO as emission layer materials, the fabricated non-doped devices exhibited pure-blue emission with Commission Internationale de l’Eclairage (CIE) coordinates of (0.16, 0.12) and (0.16, 0.15), maximum luminescences of 10,484 and 15,485 cd m–2, and maximum external quantum efficiencies (EQEs) of 10.9 and 8.3%. Besides, at a luminescence of 1000 cd m–2, the EQEs of PIAnPO-based devices can still be high at 7.7%, and the negligible efficiency roll-off was 6.0%. The device performance of both materials demonstrates their outstanding potential for commercial application.