Water and methylamine acetate synergistically induced the growth of three primary color luminous MAPbBrnX3−n@PbX(OH) microwires

Abstract

PbX(OH) (X = Cl, Br, I) is considered one of the effective encapsulation matrixes to improve the stability and luminescence efficiency of perovskites. 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. Herein, 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 structure transition from MAPbBr₃ to MAPbBr₃@PbBr(OH) MWs was 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 the MAPbBr_xAc_3−x intermediate, which induces the transformation of MAPbBr₃ into PbBr(OH) 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 MAPbBr_nX_3−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.