Successful creation of CsPb(Br1-xClx)3/ZnS core/shell perovskite nanocrystals for pure deep-blue LEDs with high luminance and efficiency

Abstract Light-emitting diodes (LEDs) are the rapidly developing core components of current display and lighting technology. Metal halide perovskite nanocrystals (MHP NCs) have recently been used as the deep-blue-light-emitting component in LEDs and are considered to have the greatest potential for growth in practical applications. However, the vulnerability of MHP NCs to the environment and the ion migration during the operation of LEDs pose formidable obstacles to the practical application of MHP NCs. Herein, we show that mixed-halide CsPb(Br1-xClx)3 NCs enclosed by epitaxially grown ZnS shells (CPBC/ZnS) are integral to ensuring a stable perovskite-based deep-blue-light-emitting diode (PeLED). We found that epitaxial ZnS shells protect the MHP NCs from the environment, and that the interparticle ion migration between MHP NCs could be effectively suppressed during LED operation, affording an exceptional external quantum efficiency (EQE) of 3.63% at an emission peak of 451 nm and a maximum luminance of 1687 cd m-2. Our results demonstrate that the epitaxial encapsulation of MHP NCs is a powerful strategy for the fabrication of high-efficiency, high-stability PeLEDs with a deep-blue emission.