DFT study of host-dopant systems of DPVBi with organophosphorus π-conjugated materials

Abstract

A detailed computational analysis of intermolecular interactions and optoelectronic properties is carried out using DFT/TD-DFT methods for the emissive materials namely 4,4'-bis(2,2′-diphenylvinyl)-1,1′-biphenyl, DPVBi, phospholes 2-thienyl 5-fluorenyl thioxophosphole, A and 2-(5-methyl) thienyl 5-fluorenyl thioxophosphole, B and the two host-dopant systems, DPVBi-A(DA) and DPVBi-B(DB). DPVBi is a classical blue emitter and, phosphole-based compounds A and B are the complementary orange emitters for generation of white light emission in Organic Light Emitting Diodes (OLEDs). The intermolecular interactions are analyzed at B2PLYPD/6-31G(d,p) level for homodimers using the data from CSD and heterodimers with possible structures as predicted at B97D/6-31G(d) level of theory. Drift mobilities, based on Marcus theory for both hole and electron transfers are estimated for DPVBi and compounds A and B in solid state. Vertical and adiabatic excitation energies are calculated for DPVBi and phospholes A and B using TD-DFT. To determine the emission energies, excited state geometry optimizations are carried out using B3LYP, CAM-B3LYP, PBE0, M06-2X functionals with 6-31+G(d,p) basis set.