Stability performance enhancement and mechanistic research of CH3NH3PbBr3 perovskite quantum dots

Organic-inorganic lead halide perovskites quantum dots (OIPeQDs) have shown excellent performance and great promise for commercial applications. However, their instability is a major challenge for their commercial viability. To address this issue, this study optimized the precursor PbBr2 to DMAPbBr3 (DMA+ = (CH3)2NH2+) and synthesis the CH3NH3PbBr3 quantum dots (QDs) by ligand-assisted reprecipitation (LARP) method at room temperature. This process aims to provide a halogen-rich environment to reduce halide vacancy defects, as well as incorporating symmetrical A-site ions, which enhances hydrogen bonding between the halogen and organic cations. The QDs-DMAPbBr3 obtained through this optimized precursor showed preferable time, water and light stability compared to those synthesized through conventional PbBr2. The result demonstrates that the QDsDMAPbBr3 maintained 85.60% of the initial photoluminescence (PL) value even after one month. To test the stability of the QDs further, the QDs were mixed with deionized (DI) water at a 20:1 ratio, and the QDsDMAPbBr3 retained 408.33% of the initial PL value after 3 h. In addition, after continuous irradiation under a 365 nm ultraviolet lamp for 20 h, the PL value of the QDs-DMAPbBr3 remained stable, at 65.48% of the initial value. These findings indicate that QDs-DMAPbBr3 possess remarkable stability, which suggests their suitability for a wide range of applications.