ABSTRACT Perovskite light‐emitting diodes (LEDs) have achieved external quantum efficiencies (EQEs) above 20% in the red, green, and blue spectral regions, yet their efficiency rapidly declines as the bandgap widens for shorter‐wavelength emission. This limitation hampers the development of high‐bandgap perovskite LEDs, including ultraviolet (UV) devices. Here, we report efficiency enhancement in violet‐emitting perovskite quantum dot LEDs through ZnCl 2 post‐treatment doping as a step toward future UV LED technologies. ZnCl 2 doping significantly improves optoelectronic performance, increasing the EQE from 0.38% to 0.90%, raising the maximum luminance from 95.29 to 156.39 cd/m 2 , and reducing the turn‐on voltage from 3.88 to 3.65 V. These results indicate that ZnCl 2 post‐treatment effectively enhances carrier transport and overall device performance, offering a promising strategy to enable efficient high‐bandgap perovskite LEDs.
Lai et al. (2026) studied this question.