Multiple “Hot exciton” channel molecular design in organic electroluminescence materials: a theoretical investigation

Abstract

The “Hot exciton” channel material can take into account both maximizing exciton utilization efficiency (EUE) and maximizing photoluminescent quantum yield (PLQY). It is a new material with broad application prospects. In this article, starting from the classical D–A molecular model system, the long-range correction functional ωb97x, which can accurately describe the CT state, was selected for the excited state calculation. We extended the D–A system to the X-B-D system. In order to preserve the large ΔE_T1–T2, we selected the NZ group as the central core B; we chose a donor group 10H-phenoxazine (X₁) and an acceptor group 1,3,4,6,7,9,9^b-heptaazap-henalene (X₂) as part X, and 10 donors with different HOMO as part D. By simulating the ground state and excited state properties of these 20 molecules, we found that compared with the traditional D–A molecule, the excited state of the X-B-D molecules underwent more CT or HLCT transition; the number of channels for the reverse intersystem crossing increased from one to multiple, which may provide a new idea for the design of new multi-channel “Hot exciton” materials.