Highly Luminescent and Stable Si‐Based CsPbBr₃ Quantum Dot Thin Films Prepared by Glow Discharge Plasma with Real‐Time and In Situ Diagnosis

Abstract Although all‐inorganic perovskite quantum dots (QDs) have outstanding optoelectronic properties, they tend to have poor stability in air and water, at high temperatures, and under light irradiation. Herein, a glow discharge plasma process incorporating real‐time and in situ diagnosis is designed for efficient encapsulation to improve the stability of CsPbBr 3 QD films. An ammonia/silane plasma which has less destructive effects on CsPbBr 3 QDs is used in plasma‐enhanced chemical vapor deposition to produce a‐SiN x :H on the CsPbBr 3 QDs. The a‐SiN x :H encapsulating layers endow CsPbBr 3 QDs with long‐term stability during exposure to air, at a high temperature (205 °C), and in water. In contrast to severe degradation of pure CsPbBr 3 QDs under UV illumination, the CsPbBr 3 QDs/a‐SiN x :H films show more than 5‐folds increase in photoluminescence intensity after UV illumination for 80 d and long‐term stability is observed after UV illumination for 140 d. The plasma treatment not only stabilizes CsPbBr 3 QDs, but enhances photoluminescence efficiency by combining with illumination as well. The nanocomposite films assembled into commercial InGaN chips feature strong cold white emission. Our results reveal a practical way to design and fabricate highly luminescent as well as stable Si‐based CsPbBr 3 QD films for future development of optoelectronic devices.