Combination of passivated Si anode with phosphor doped organic to realize highly efficient Si-based electroluminescence

Silicon light source plays a key role in silicon optoelectronics, but its realization is an extremely challenging task. Although there are long-term intensive efforts to this topic, the power conversion efficiency (PCE) of the silicon-based electroluminescence is still no more than 1%. In this present report, a highly efficient silicon light source has been achieved. The device structure is p-Si (5 Omega cm)/SiO2(similar to 2nm)/NPB/CBP: (ppy)(2)Ir(acac)/Bphen/Bphen: Cs2CO3/Sm/Au. The SiO2 passivated Si is the anode having a suitably high hole-injection ability, and CBP:(ppy)(2)Ir(acac) is a highly efficient phosphor doped organic material. The device turn-on voltage is 3.2 V. The maximum luminance efficiency and maximum luminous power efficiency reach 69 cd/A and 62 lm/W, respectively, corresponding to a maximum PCE of 12% and an external quantum efficiency of 17%. (C) 2008 Optical Society of America.