Organic nanostructures of thermally activated delayed fluorescent emitters with enhanced intersystem crossing as novel metal-free photosensitizers

Organic nanostructures of thermally activated delayed fluorescent emitters with enhanced intersystem crossing as novel metal-free photosensitizers†

Jinfeng Zhang,‡^a Wencheng Chen,‡^a Rui Chen,^a Xiao-Ke Liu,^a Yuan Xiong,^b Stephen V. Kershaw,^b Andrey L. Rogach,^b Chihaya Adachi,*^c Xiaohong Zhang^d and Chun-Sing Lee

*^a

Author affiliations

* Corresponding authors

^a Center of Super-Diamond and Advanced Films (COSDAF), and Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, P. R. China
E-mail: apcslee@cityu.edu.hk

^b Department of Physics and Materials Science and Centre for Functional Photonics, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, P. R. China

^c Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Japan
E-mail: adachi@cstf.kyushu-u.ac.jp

^d Institute of Functional Nano & Soft Materials (FUNSOM), and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu, P. R. China

Abstract

We applied organic nanostructures based on thermally activated delayed fluorescent (TADF) emitters for singlet oxygen generation. Due to the extremely small energy gaps between the excited singlet states (S₁) and triplet states (T₁) of these heavy-metal-free organic nanostructures, intersystem conversion between S₁ and T₁ can occur easily. This strategy also works well for exciplex-type TADF emitters prepared by mixing suitable donors and acceptors which have no TADF characteristics themselves.