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Experimentally Observed Reverse Intersystem Crossing‐Boosted Lasing
Author(s) -
Zhou Zhonghao,
Qiao Chan,
Wang Kang,
Wang Lu,
Liang Jie,
Peng Qian,
Wei Zhiyou,
Dong Haiyun,
Zhang Chuang,
Shuai Zhigang,
Yan Yongli,
Zhao Yong Sheng
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202008940
Subject(s) - intersystem crossing , lasing threshold , excited state , population inversion , optoelectronics , materials science , population , photochemistry , laser , gain switching , fluorescence , chemistry , atomic physics , optics , physics , singlet state , wavelength , demography , sociology
Thermally activated delayed‐fluorescent (TADF) materials are anticipated to overcome triplet‐related losses towards electrically driven organic lasers. Thus far, contributions from triplets to lasing have not yet been experimentally demonstrated owing to the limited knowledge about the excited‐state processes. Herein, we experimentally achieve reverse intersystem crossing (RISC)‐boosted lasing in organic microspheres with uniformly dispersed TADF emitters. In these materials, triplets are continuously converted to radiative singlets through RISC, giving rise to reduced losses in stimulated emission. The involvement of regenerated singlets in population inversion results in a thermally activated lasing; that is, the lasing intensity increases with increasing temperature, accompanied by accelerated depletion of the excited‐state population. Benefiting from the suppression of triplet accumulations by RISC processes, a high‐repetition‐rate microlaser was achieved.