Efficient and Stable Mg²⁺-Doped CsPbCl₃ Nanocrystals for Violet LEDs

It has been a challenge to prepare perovskite violet light-emitting diodes due to the low luminous efficiency and poor stability of the relevant materials. In this work, the defect state density of CsPbCl₃ NCs was reduced by Mg²⁺ doping, so the photoluminescence quantum efficiency (PLQY) was increased by 57 times (from 1.3% to 75.8%) compared with undoped CsPbCl₃ NCs. The doped CsPbCl₃ NCs had no phase change in the atmosphere over 180 days, and the PLQY was only dropped by 19%. Based on the highly efficient luminescence and high stability of Mg²⁺-doped CsPbCl₃ NCs, violet-light-emitting diodes were fabricated. The maximum brightness of device was 135 cd/m², and the peak EQE reached 0.1%.