Photoelectric properties of host materials based on diphenyl sulfone as acceptor and the performances in green phosphorescent OLEDs

Three novel diphenyl sulfone derivatives of PPSPCz, PSPSF and DPPSPF with different donors carbazole, spirobifluorene and spirofluorene were synthesized in order to investigate the effects of donors on the properties of the host materials. The photoluminescence spectrum of PPSPCz exhibited red-shift than that of PSPSF and DPPSPF because of the stronger ability of carbazole. The triplet energy levels of PPSPCz, PSPSF and DPPSPF were 2.64, 2.48 and 2.81 eV, respectively. The green PhOLEDs were prepared by using the titled materials as hosts and tris(2-phenylpyridine)iridium [Ir (ppy)3] as emitter. The PhOLED based on PPSPCz exhibited the better performance with the ηc, max of 53.8 cd/A, ηp, max of 38.2 l m/W and EQEmax of 15.4%, respectively.