Improving Pure Organic Room-Temperature Phosphorescence by Substituent Effect of Thianthrene

Abstract

To gain insights into the potential of thianthrene (TA), its substituent effects were systematically studied on the room-temperature phosphorescence (RTP) properties, including the electron-donating and electron-withdrawing substituents at 1- and 2-positions of TA, respectively. Both theoretical and experimental investigations show that the 2-position electron-withdrawing substituents greatly enhance RTP performance than the 1-position substituents, while the situation is exactly the opposite for electron-donating substituents. Compared with the 1-position substitution, the 2-position electron-withdrawing substituents induce the higher RTP radiation rate and lower non-radiation rate, in favor of the enhancement of RTP efficiency. Furthermore, the introduction of phenylene into the 2-position substitution greatly suppresses the non-radiation, resulting in the simultaneously improved RTP efficiency and elongated lifetime. Finally, using these RTP materials, the dynamically reversible operations of information (write-read-erase) are realized, as well as the encryption and time-dependent decryption demonstration. This work not only provides a better understanding of structure–property relationship on TA-based RTP materials, but also suggests an intramolecular structural modification strategy to improve the performance of pure organic RTP materials.