LAUSR

We report on a low-temperature solution processed trifunctional inorganic p-type semiconductor, copper(I) thiocyanate (CuSCN), as a hole injection/transporting and electron-blocking layer for high-efficiency organic light-emitting diodes (OLEDs). The electroluminescence (EL) characteristics of CuSCN and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) based devices were studied with the structure of 4,4′-bis(N-carbazolyl)-1,1′-biphenyl as the host, bis[2-(2-pyridinyl-N)phenyl-C](acetylacetonato)iridium(III) [(ppy)2Ir(acac)] as the green emitter, 2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1H-benzimidazole) as the electron transporting layer, and lithium fluoride/aluminum as the cathode electrode. The power efficacies for the CuSCN based devices are found to be 51.7 and 40.3 lm/W at 100 and 1000 cd/m2, respectively, which are 13 and 60% higher than the PEDOT:PSS based counterparts. These are the highest power efficacies ever reported for this particular device architecture. The superior E...