Silane-and triazine-containing hole and exciton blocking material for high-efficiency phosphorescent organic light emitting diodes

摘要

One of the important factors for high efficiency phosphorescent organic light-emitting devices is to confine triplet excitons within the emitting layer.We synthesized and characterized a new hole blocking material containing silane and triazine moieties,2,4-diphenyl-6-(4'-triphenylsilanyl-biphenyl-4-yl)-l,3,5-triazine (DTBT).Electrophosphorescent devices fabricated using the material as the hole-blocking layer and N,N'-dicarbazolyl-4,4'-biphenyl (CBP) doped with fac-tris(2-phenylpyridine)iridium [Ir(ppy)3] as the emitting layer showed a maximum external quantum efficiency (eta_(ext)) of 17.5% with a maximum power efficiency (eta_p) of 47.8 1m W~(-1),which are much higher than those of devices using bathcuproine (BCP) (eta_(ext)=14.5%,eta_p=40.0 lm W~(-1)) and 4-biphenyloxolate aluminium(III) bis(2-methyl-8-quinolinato)-4-phenylphenolate (BA1q) (eta_(ext)=8.1%,eta_p=14.2 lm W~(-1)) as hole-blocking layers.