Suppression of non-radiative recombination toward high efficiency perovskite light-emitting diodes

Nickel oxide (NiO) would be an alternative hole transport layer for perovskite light-emitting diodes (PeLEDs). However, the performances of NiO-based PeLEDs are still inferior due to the adverse non-radiative recombination at the interface. Here, a poly(9-vinlycarbazole) (PVK) layer is inserted between the perovskite and the NiO film. The photoluminescence quantum yield is dramatically enhanced from 23% to 54% in the presence of PVK layer owing to suppression of the non-radiative recombination. Combined with the favorable hole injection from the ladder energy band scheme of NiO/PVK layer, an external quantum efficiency of 11.2% for a green PeLED is achieved. This work demonstrates the importance of interface control to boost the radiative recombination rate for high performance PeLEDs.