LAUSR

Abstract Templated synthesis of CH3NH3PbBr3 perovskite nanocrystals is facile, high-yield, ligand-free, and is another effective method aside from the colloidal method. However, the quantum yield (QY) is still inferior to that of the colloidal synthesized ones. In this report, we show that CH3NH3PbBr3 nanocrystal within mesoporous silica with QY of 75% and full width at half-maximum (FWHM) of 22 nm are obtained through manipulating the molar ratio of CH3NH3Br versus PbBr2 in precursor solution. It is found that excess CH3NH3Br can passivate the surface trap states, reduce nanocrystal size and narrow down the size distribution effectively. These features contribute to the rising of QY, blue-shifting of emission maximum and narrowing down of FWHM. The influence of excess CH3NH3Br can be interpreted in terms of enrichment on the interface of solvent/air because of amphipathy. Moreover, these CH3NH3PbBr3 - mesoporous silica composites present good stability. They preserve 90% of its initial QY after a storage in wet weather with relative humidity of 70 ± 5% for 3 months. The synthesis method proposed in this research provides an effective way to achieve perovskite nanocrystals within mesoporous silica with high efficiency and stability.