中科院化学所赵永生团队开发了用于激光显示的有机微晶体的热激活激光策略。相关研究成果发表在2021年11月19日出版的《美国化学会杂志》。

热激活延迟荧光（TADF）材料有望克服电泵浦有机激光器的三重态光损耗。然而，由于在凝聚态中三重态到单重态的上转换受到严重抑制，因此很难在这些材料中建立布居数反转。

该文中，研究人员报告了溶液处理共组装微晶中的热激活激光，其中TADF染料均匀分散到晶体基质中，以确保有效的反向系统间交叉（RISC）。RISC获得的暗态三重态激子被有效地转化为辐射单重态激子，随后参与了布居数反转，以不同寻常的温度依赖性来增强激光。由于良好的兼容性，通过掺杂各种TADF激光染料可在整个可见光谱上调谐激光波长。采用模板约束溶液生长法，将三色TADF微激光器精确地阵列成周期性像素阵列。

以制备的TADF微激光器阵列为显示面板，在可编程激励下实现了逼真的激光显示。研究结果为最小化高性能激光器的三重态相关能量损失提供了有价值的启示。

附：英文原文

Title: Thermally Activated Lasing in Organic Microcrystals toward Laser Displays

Author: Tongjin Zhang, Zhonghao Zhou, Xiaolong Liu, Kang Wang, Yuqing Fan, Chuang Zhang, Jiannian Yao, Yongli Yan, Yong Sheng Zhao

Issue&Volume: November 19, 2021

Abstract: Thermally activated delayed fluorescent (TADF) materials are promising to overcome triplet-induced optical loss in the pursuit of electrically pumped organic lasers. However, population inversion is difficult to establish in these materials due to the severe suppression of triplet-to-singlet upconversion in their condensed states. In this work, we report thermally activated lasing in solution-processed coassembled microcrystals, where TADF dyes were uniformly dispersed into crystalline matrices to ensure an efficient reverse intersystem crossing (RISC). The dark-state triplet excitons harvested by the RISC were effectively converted into radiative singlet excitons, which subsequently participated in the population inversion to boost lasing with an unusual temperature dependence. The lasing wavelength was tuned over the full visible spectrum by doping various TADF laser dyes, owing to the excellent compatibility. Trichromatic TADF microlasers were precisely patterned into periodic pixelated arrays by a template-confined solution-growth method. With as-prepared TADF microlaser arrays as display panels, vivid laser displays were achieved under programmable excitation. These results offer valuable enlightenment to minimize triplet state-related energy losses toward high-performance lasers.

DOI: 10.1021/jacs.1c08824

Source: https://pubs.acs.org/doi/10.1021/jacs.1c08824