Phosphorescent organic light emitting devices having a hole transporting cohost material in the emissive region

Abstract

An improved OLED includes an emissive layer disposed between a cathode and an anode where the emissive layer includes a multi-component host material and a phosphorescent emitter material. The host material includes at least a first host compound and a second host compound, where the first host compound is hole-transporting host compound having the general formula wherein R, R, R, R, R, and Rmay be the same or different fluorine atom, chlorine atom, a deuterium atom, a cyano group, a trifluoromethyl group, a nitro group, linear or branched alkyl group (C1-C6), cyclo-alkyl group (C5-C10), linear or branched alkoxy group (C1-C6), cyclo-alkoxy group (C5˜C10), substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, r, r, r=0, 1, 2, 3, or 4 r, rr; =0, 1, 2 or 3 n=0 or 1, and Ar, Ar, and Armay be the same or different, substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, deuterium substituted aromatic hydrocarbon group, deuterium substituted aromatic heterocyclic group, or deuterium substituted condensed polycyclic aromatic group.