Theoretical Investigations of the Spiro‐Annulated Triphenylamine/ N‐Phenylcarbazole‐Based Ambipolar Host Materials for OLEDs

Abstract

AbstractA series of spiro‐annulated triphenylamine/N‐phenylcarbazole derivatives as ambipolar host molecules have been designed by linking different electron acceptors (i. e., diphenylphosphine, phenylsulfone, triphenylsilane and diphenylborane). To reveal their electronic structures, optoelectronic properties and structure‐property relationships of the host materials, a throughout investigation was implied using density functional theory (DFT) and time‐dependent density functional theory (TDDFT) calculations. Results show that the triplet energy (ET), HOMO and LUMO energy levels, as well as some other properties i. e. ionization potentials (IPs), electron affinities (EAs), reorganization energies (λ) can be tuned by chemical modifications of different electron acceptors. The host‐guest models have also been built to investigate the match of the hosts and the reference guests. Comprehensively considering these indexes, the potential performance of 10‐phenyl‐2′‐(phenylsulfonyl)‐10H‐spiro[acridine‐9, 9′‐fluorene] (SOSTF) is a big leap in comparison with experimental host material diphenyl(10‐phenyl‐10H‐spiro[acridine‐9, 9′‐fluoren]‐2′‐yl)phosphine oxide (POSTF). It has been proved that a spiro‐annulated structure can be modified in constructing high ET host material for blue phosphorescent organic light‐emitting diodes.