Theoretical study of diphenylsulfone derivatives for blue thermally activated delayed fluorescence emitters

Abstract

Novel thermally activated delayed fluorescence (TADF) emitters were designed with diphenylsulfone (DPS) as an electron acceptor and carbazole derivatives as electron donors and their electronic and optical properties were investigated theoretically for applications to blue organic light-emitting diodes (OLEDs). By using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations, we obtained the electron distributions of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) as well as the energy of the lowest singlet (S₁) and lowest triplet (T₁) excited states. We show that 2mDTC-DPS would be a suitable blue OLED emitter because it has sufficiently small ΔE_ST value, which is favorable for a reverse intersystem crossing (RISC) process from T₁ to S₁ states and an emission wavelength of 429 nm with sufficiently large F values.

Keywords:

• density functional theory (DFT)
• time-dependent density functional theory (TD-DFT)
• organic light-emitting diode (OLED)
• thermally activated delayed fluorescence (TADF)

Additional information

Funding

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1D1A1B03028107 and 2015R1A6A1A03031833).