Water and Methylamine Acetate Synergistic Induced the Growth of Three Primary Color Luminous MAPbBrnX3-n@PbX(OH) Microwires

PbX(OH) (X=Cl, Br, I) is considered one of the effective encapsulation matrixes to improve the stability and luminescence efficiency of perovskite. Several strategies have been explored to construct perovskite@PbBr(OH) composites with high photoluminescence quantum yield. However, there is limited research on their precise growth kinetics mechanism and morphology control. Here, PbBr2 microwires (MWs) were applied to act as the lead source and serve as a skeleton frame for the growth of CH3NH3PbBr3 (MAPbBr3) MWs. The structures transition from MAPbBr3 to MAPbBr3@PbBr(OH) MWs were triggered by the synergistic effect of H2O and CH3NH3OOCCH3 (methylamine acetate, MAAc). All components and synthesis processes used in this system are explicit which allows a more in-depth exploration of the MAPbBr3@PbBr(OH) formation kinetics. The results indicate that the hydrolysis of MAAc provides OH- and partly replaces Br- ions in MAPbBr3 to form MAPbBrxAc3-x intermediate, which induces the transformation of MAPbBr3 into PbBr(OH) and until the stable MAPbBr3@PbBr(OH) microwires are formed. Based on this growth kinetics process, utilizing H2O-MAAc and extra sodium halide (NaCl, NaI) mixture can synthesize MAPbBrnX3-n@PbX(OH) (X=Cl, I) microwires successfully. Our study can open a new avenue for developing high-efficiency and high-stability fluorescent hybrid perovskites for three primary color detectors, lasing cavities, and sensors.