A representative metal halide perovskite, CsPbX 3 , has received much attention for its high photoluminescence (PL) effi ciency

and broad emission spectral range covering ultraviolet to infrared. Even with the focused investigations, they still suff er from

poor emission stability from surface-induced defects. The inherent instability of perovskites is caused by moisture in the

ambient, which leads to a reduction in the luminescence effi ciency and deterioration of emission stability. In this study, we

report a method to annihilate the surface defects in CsPbBr 3 nanocrystals (NCs), which enhances their photoluminescence

effi ciency by forming a SiO x shell structure using a 3-aminopropyltriethoxysilane (APTES). The APTES was treated during

the synthesis of CsPbBr 3 NCs through supersaturation and re-precipitation processes. The optical investigations confi rmed

that the PL intensity and emission stability of the CsPbBr 3 NCs improved with the APTES treatment. The structural investigations

using X-ray diff raction and transmission electron microscopy showed that optical analysis was carried out through

photoluminescence and laser optical analysis using lasers at 400 nm and 365 nm wavelengths. These fi ndings present an

innovative solution to the instability issues of CsPbBr 3 and suggest possibilities for its utilization in various application

fi elds. Future research should focus on further understanding the scalability of this method and its practical applicability.