All-solution-processed, highly efficient and stable green light-emitting devices based on Zn-doped CsPbBr3/ZnS heterojunction quantum dots

Abstract

The low-cost, solution-processed and stable perovskite quantum dots (QDs) light-emitting diodes (QLEDs) have great potential applications for the new-generation displays technology and white-LEDs. The stability of perovskite QDs has been improved via polymers or inorganic encapsulation strategies, but at the cost of their semiconducting properties, so it is not suitable for active light-emitting devices. In this paper, the Zn-doped CsPbBr3/ZnS QDs heterojunction were fabricated via a simple solution-phase method, which demonstrated simultaneously enhanced the optical properties and stability of perovskite QDs films without damaging their semiconducting properties. The photoluminescence quantum yields and stability of the Zn-doped CsPbBr3/ZnS heterojunction QDs films have been significantly improved because of good surface passivation on the surface defects of perovskite QDs with ZnS nanoclusters and Zn2+ doping. Finally, solution-processed n-ZnO nanoparticles (NPs) and p-NiO NPs as carrier transport layers are used to fabricate all-inorganic Zn-doped CsPbBr3/ZnS QLEDs. The QLEDs show high-efficiency green light emission with a maximum luminance of 8600 cd/m2 and external quantum efficiency of 4.8%. Moreover, the researched green perovskite QLEDs also show good working stability after a long test time in the outside environment. This study may provide an effective way for the preparation high-performance perovskite QLEDs with good environmental stability, making practical applications possible.