Fabrication and optimization of hole transport layer NiO for all inorganic perovskite light emitting diodes

Perovskite light emitting diodes (PeLEDs) have attracted massive research interest in recent years. In order to obtain better luminescent properties, most attention is paid to the emitting layer perovskite materials. Actually, the other layers such as the transport layers should also be optimized. We proposed the optimization of hole transport layer NiO materials by magnetron sputtering. Effects of RF power, sputtering pressure and sputtering argon-oxygen ratio on surface morphology and electrical properties of NiO film were studied. Sputtering power, pressure and Ar/O-2 were set at 90 W, 25 mTorr and 10/40 over the past parameters to optimize the NiO film in our previous ZnO/CsPbBr3/NiO structured all inorganic perovskite LED. SEM, PL, XRD measurements were conducted to characterize the CsPbBr3 having good morphologies, light emitting characteristics, and crystal quality. PeLEDs with and without the optimized hole transport layer NiO were compared. The EL results show that the optimized PeLED has much better electroluminescence characteristics than the one without optimization. Our work demonstrated a possible way to improve the luminescence properties of the PeLED.