Au generation centres doped n⁺-Si: hole-injection adjustable anode for efficient organic light emission

An organic light-emitting diode (OLED) with an n-Si-anode usually has an efficiency evidently lower than the OLED with the same structure with a p-Si-anode due to insufficient hole injection from the n-Si anode compared with the p-Si-anode. In this study, we find that introducing Au as generation centres with a suitable concentration into the n + -Si anode can enhance hole injection to match electron injection and then considerably promote the power efficiency. With optimizing Au generation centre concentration in the n + -Si anode, the OLED with a structure of n + -Si: Au/NPB/AlQ/Sm/Au reaches a highest power efficiency of 1.0 lm W −1 , evidently higher than the reported highest power efficiency of 0.2 lm W −1 for its p-Si-anode counterpart. Furthermore, when the electron injection is enhanced by adopting BPhen:Cs 2 CO 3 partly instead of AlQ as the electron transport material, and the Au generation centre concentration in the n + -Si anode is promoted correspondingly, then a highest power efficiency of 1.8 lm W −1 is reached. The role of Au generation centres in the n + -Si anode is discussed.