Synergistic Effect of Zn²⁺ Cation Doping and Te²⁻ Anion Passivation on CsPbBr_xI_3‐x Nanocrystals for Efficient Perovskite Light‐Emitting Diodes

Abstract The challenges of instability and surface defects in CsPbBr_xI_3‐x nanocrystals (NCs) pose significant limitations on their potential application in high‐performance pure‐red perovskite light‐emitting diodes (PeLEDs). Herein, a synergistic strategy of divalent cation (Zn²⁺) doping and anion (Te²⁻) passivation is proposed to solve these issues. Density functional theory analysis reveals that the synergistic effect can not only reduce the formation energy of CsPbBr_xI_3‐x NCs but also increase theiodide vacancy defect formation energy of CsPbBr_xI_3‐x NCs. Consequently, the optimized Zn²⁺/Te²⁻ co‐modified CsPbBr_xI_3‐x NCs exhibit significantly enhanced stability with a near‐unity photoluminescence efficiency. Pure‐red PeLEDs based on these CsPbBr_xI_3‐x NCs possess outstanding spectral stability with a maximum external quantum efficiency and luminance of 16.1% and 1397.2 cd m⁻², respectively. This synergistic strategy provides a new approach for enhancing the performance of mixed halide perovskite NCs and the corresponding optoelectronic devices.