Enhanced electroluminescence utilizing p-sexiphenyl for the blue light source

Enhanced blue light electroluminescence has been observed utilizing p-sexip henyl (6P). The heterostructure device with N,N ' -diphonyl-N,N '-(3-methyl phenyl)-1,1 ' -biphenyl-4,4 ' -diamine (TPD) hole transporting layer and 6P emissive layer emits blue light centered at approximately 423 run, and the EL intensity reaches as high as 3400 cd/m(2) at an applied voltage of 10 V . The heterostructure device emits intensity two orders of magnitude higher than a conventional single layer device. The multiplayer structure device of 4,4 ' -bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl (alpha -NPD), 4,4 ' -d icarbazolyl-1,1 ' -biphenyl (CBP) and 6P utilizing 6P as a electron transpo rting layer has a emission peak at approximately 430 nm. The EL intensity f rom the alpha -NPD layer reaches as high as 2500 cd/m(2) at an applied volt age of 13 V. The mechanism of enhanced emission from heterostructure utiliz ing 6P has been discussed. (C) 2001 Elsevier Science BN. ALI rights reserve d.