Towards red thermally activated delayed fluorescence emitter: Molecular design and property prediction of phenothiazine-triphenyltriazine derivative

• Published in: Computational and theoretical chemistry 2023-10, Vol.1228, p.114277, Article 114277
• Main Authors: An, Lin, Su, Ruiqiang, Sun, Yali, Song, Chongping, Wang, Qinggao
• Format: Article
• Language: English
• Subjects: DFT calculations; N-position; PTZ-TRZ TADF molecules; Red emitters
• ISSN: 2210-271X
• DOI: 10.1016/j.comptc.2023.114277

A series of thermally activated delayed fluorescence (TADF) molecules with the linkage of the electron-donating group (phenothiazine, PTZ) and electron-withdrawing groups (2,4,6-triphenyl-1,3,5-triazine type, TRZ) have been designed and investigated for efficient red TADF emitters by means of quantum chemical calculations. The geometrical and electronic structures, absorption and emission properties, reverse intersystem crossing (RISC), radiative and nonradiative decay processes of the PTZ-TRZ-based molecules were analyzed. The calculated results indicate that the designed molecules possess the relatively large RISC rates (>105 s−1) and exhibit the red emission, indicating that they have the potential to be an efficient red emitting TADF material. Furthermore, the position of N atom in the TRZ acceptor group have significant effects on RISC process and emission color. This work provides in-depth understanding of the structure–property relationship of PTZ-TRZ-based TADF molecules, and offers the guideline for the screening of the efficient pure red TADF emitters. [Display omitted] •A series of PTZ-TRZ-based TADF molecules were investigated theoretically.•The designed molecules possess the small ΔEST and the large RISC rates (> 105 s−1).•The emission wavelengths of the designed molecules are red-shifted up to 641 nm.•N positions in TRZ group could tune the properties of PTZ-TRZ-based TADF molecules.