CsPbBr₃ Nanocrystal Light-Emitting Diodes with Efficiency up to 13.4% Achieved by Careful Surface Engineering and Device Engineering

Perovskite nanocrystals (NCs) have gained great interest for next-generation light-emitting diodes (LEDs) prized for their spectrally tunable, narrow luminescence and their defect-tolerant electronic structure. Here, we provide a careful surface engineering to balance the passivation and charge injection by controlling the ligand density of didodecyl dimethyl ammonium bromide on NCs, which not only offers an improved photoluminescence quantum yield of >70% for NCs but also guarantees the effective charge injection and transportation of CsPbBr₃ NC films for fabricating LEDs. Additionally, the optimization of the hole transport layer was implemented to offer more balanced charge transportation, which further improved the performance of CsPbBr₃ NC-based LEDs with a peak external quantum efficiency of 13.4%.