Bright and efficient light-emitting diodes based on MA/Cs double cation perovskite nanocrystals

Abstract

A high quantum yield, tunable band gap, and high color purity of perovskite nanocrystals make this class of materials attractive for electronic and optoelectronic applications in devices including solar cells, photodetectors, and light emitting diodes. Herein, we report for the first time the facile synthesis of perovskite nanocrystals based on (CH₃NH₃)_1−xCs_xPbBr₃. The emission properties, photoluminescence and stability of the mixed-cation perovskite nanocrystals have been intensively studied, which are significantly related to the content of cesium in the composition. The as-obtained (CH₃NH₃)_1−xCs_xPbBr₃ nanocrystals were employed as the emission layer in perovskite light emitting diodes, and the device fabricated with the optimized perovskite nanocrystals (Cs doping x = 0.3) showed a maximum luminescence of 24 500 cd m⁻², nearly ten-fold higher than those for the previous reported perovskite devices based on MAPbBr₃ nanocrystals. This study opens a new avenue for the fabrication of efficient perovskite nanocrystals and provides great potential of developing perovskite LEDs based on mixed-cation perovskite nanocrystals.