Pure bromide-based inorganic perovskite sky-blue light-emitting diodes through phase control by the NiOx anode interface

Abstract

Perovskite light-emitting diodes (PeLEDs) have been considered as a potential technology for next-generation lighting and displays. However, the relatively primitive blue-emitting devices obtained have limited the development of PeLEDs. Therefore, there is an urgent need to develop new preparation methods and regulation strategies for blue PeLEDs. Herein, a simple and efficient strategy has been reported for blue PeLEDs based on pure bromide perovskites without any doping using a NiO_x anode interface. The effects of NiO_x on the composition and morphology of the perovskite films were analyzed in detail. NiO_x replaced PEDOT:PSS as the anode interface layer, which promoted the formation of Cs₄PbBr₆, thus effectively restricting the growth of CsPbBr₃ and widening the perovskite bandgap, achieving a blue PeLED. Eventually, a sky-blue PeLED with a maximum luminance of 1610 cd m⁻² and a maximum external quantum efficiency of 1.58% was achieved. Our work will provide a simple and feasible scheme for the development of efficient and stable blue PeLEDs based on pure bromide perovskites, as well as providing useful studies for the realization of blue PeLEDs through phase composition regulated by interface control.