Volume 250, 2024

Luminescence mechanism analysis of a TADF molecule showing peculiar thermal behavior

Abstract

In recent years, much attention has been paid to the development of thermally activated delayed fluorescence (TADF) materials with short delayed-fluorescence lifetimes to improve the device performances of OLEDs. In principle, by reducing the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) overlap, while the energy difference between S1–T1EST) and activation energy (Ea) can be reduced, and the reverse intersystem crossing rate constant (kRISC) can be accelerated, a decrease in the radiative rate constant happens, necessitating an advanced molecular design. Furthermore, a molecule based on heptazine as a parent skeleton has recently been found to have a peculiar temperature dependence of luminescence decay, suggesting a negative gap (NG) material. In this report, we show that 9-[1,4]benzoxaborino[2,3,4-kl]phenoxaborine-7-yl-1,3,6,8-tetramethyl-9H-carbazole (TMCz-BO), a donor–acceptor linked TADF molecule with a very short delay lifetime of 750 ns, exhibits a peculiar thermal behavior similar to that of NG materials based on the temperature dependence of its luminescence decay in solution.

Graphical abstract: Luminescence mechanism analysis of a TADF molecule showing peculiar thermal behavior

Associated articles

Article information

Article type
Paper
Submitted
22 Ndz 2023
Accepted
25 Ndz 2023
First published
30 Huk 2023

Faraday Discuss., 2024,250, 233-250

Luminescence mechanism analysis of a TADF molecule showing peculiar thermal behavior

Y. Tsuchiya, K. Mizukoshi, M. Saigo, T. Ryu, K. Miyata, K. Onda and C. Adachi, Faraday Discuss., 2024, 250, 233 DOI: 10.1039/D3FD00151B

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