Stability Enhancement in All‐Inorganic Perovskite Light Emitting Diodes via Dual Encapsulation

Abstract Addressing the challenge of lighting stability in perovskite white light emitting diodes (WLEDs) is crucial for their commercial viability. CsPbX 3 (X = Cl, Br, I, or mixed) nanocrystals (NCs) are promising for next‐generation lighting due to their superior optical and electronic properties. However, the inherent soft material structure of CsPbX 3 NCs is particularly susceptible to the elevated temperatures associated with prolonged WLED operation. Additionally, these NCs face stability challenges in high humidity environments, leading to reduced lighting performance. This study introduces a two‐step dual encapsulation method, resulting in CsPbBr 3 @SiO 2 /Al 2 SiO 5 composite fibers (CFs) with enhanced optical stability under extreme conditions. In testing, WLEDs incorporating these CFs, even under prolonged operation at high power (100 mA for 9 h), maintain consistent electroluminescence (EL) intensity and optoelectronic parameters, with surface temperatures reaching 84.2 °C. Crucially, when subjected to 85 °C and 85% relative humidity for 200 h, the WLEDs preserve 97% of their initial fluorescence efficiency. These findings underscore the efficacy of the dual encapsulation strategy in significantly improving perovskite material stability, marking a significant step toward their commercial application in optoelectronic lighting.