Unraveling Photophysical Properties of 4CzIPN Doped in Different Hosts: a Theoretical Study

Abstract

The development of both the thermally activated delayed fluorescence (TADF) emitter and host materials plays a crucial role in achieving high quantum efficiency for organic light-emitting diode (OLED) devices.While numerous host materials have been designed and used for TADF emitters, the structure-property relationship of hosts and their influence on the luminescent properties of TADF emitters remain relatively unexplored.In this work, the structure-property relationship of 13 host materials and their influence on the luminescent properties of the classical TADF molecule 4CzIPN are investigated. Based on molecular dynamics (MD) simulation, the doped host-guest systems at different times are selected for computational and average statistical analyses. Our results reveal that mCP, a commonly used host, weakens Dexter energy transfer (DET), suppresses structural variation, and facilitates pure light emission from 4CzIPN. While CBP can enhance oscillator strength and spin-orbit coupling (SOC) of 4CzIPN in doped film. The newly designed host material, mCP-OMe, which shares structural similarities with mCP, combines the advantages of both mCP and CBP. 4CzIPN in mCP-OMe:4CzIPN films exhibits reduced non-radiative loss, higher oscillator strength, and an enhanced upconversion process. The results obtained through cluster analysis of the structure are found to be similar to the average statistical results. This study provides a theoretical foundation for selecting and designing more efficient host materials for 4CzIPN.