Long-Term Stability in α-CsPbI3 Quantum Dots via a Nonvacuum Ag+ Doping Strategy

Black phase CsPbI3 quantum dots (QDs) have garnered significant research interest due to their remarkable properties in optoelectronic applications. However, their inherent instability and low phase stability often lead to an undesired transformation into an orthorhombic yellow phase. In this study, we propose an innovative approach to synthesize Ag+ doped CsPbI3 QDs in a nonvacuum environment. The theoretical calculations and experimental results demonstrate that Ag+ doping substantially increases the formation energy and Goldschmidt tolerance factor, resulting in an enhanced thermodynamic stability and photoluminescence quantum yield (PLQY). The resulting Ag+ doped CsPbI3 QDs exhibit an impressive PLQY of up to 97% and maintain their black phase for over 60 days. This novel nonvacuum synthesis approach holds great potential for producing high-quality all-inorganic perovskite CsPbX3 QDs. To demonstrate the practical applications, we fabricate a white light-emitting diode (WLED) using the Ag+ doped CsPbI3 QDs, achieving Commission Internationale de I’Eclairage (CIE) color coordinates of (0.36, 0.26). These findings highlight the broad prospects of CsPbI3 QDs in lighting and display technologies.