Theoretical arrangement of thermally activated delayed fluorescence as host for fluorescent emitter with blue to red emission

Thermally activated delayed fluorescence (TADF) emitter is applied to obtain high triplet exciton utilization through reverse intersystem crossing process. However, for efficient TADF emitter, the contradiction between high efficiency and utilization need to be carefully balanced. In this work, we provide a theoretical design strategy to realize high exciton utilization and high luminescence efficiency simultaneously by taking the TAN molecules as host and efficient fluorescent luminescence molecules as guest to form TADF-host:fluorescence-guest system. Through investigating the photophysical properties by optimal Hartree-Fock (OHF) method, different TADF-host and various fluorescence-guest schemes arc arranged. Moreover, large overlap between the emission spectra of TADF-host and the absorption spectra of fluorescence-guest indicates efficient Forster energy transfer process. Thus, five systems with blue to red emission are obtained. Furthermore, the charge transfer properties are studied by Marcus equation, efficient charge mobility and balanced charge transfer can be expected for studied systems which are important in constructing organic light emitting diodes (OLEDs). This work could provide promising emitting layer architecture for OLEDs with ultimate performance. (C) 2019 Elsevier B.V. All rights reserved.