Encapsulation of Pb-Free CsSnCl 3 Perovskite Nanocrystals with Bone Gelatin: Enhanced Stability and Application in Fe 3+ Sensing.

The toxicity of the Pb element limits the large-scale application of inorganic cesium-lead halide (CsPbX 3 , with X = Cl, Br, and I) perovskite nanocrystals (NCs). Pb-free cesium-tin halide (CsSnX 3 ) NCs have emerged as a viable alternative because of its excellent photoelectric conversion efficiency. However, the applications are hampered by its poor stability and low photoluminescence quantum yield (PLQY). In this study, extraordinarily stable CsSnCl 3 NCs were prepared by exploiting bone gelatin as surface capping agents, which retain 95% of the photoluminescence intensity in water for 55 h. Additionally, after bone gelatin encapsulation, the PLQY of CsSnCl 3 NCs was found to increase from 2.17% to 3.13% for the uncapped counterparts because of an improved radiative recombination rate. With such remarkable optical properties of the bone gelatin-CsSnCl 3 NCs, metal ions like Fe 3+ in aqueous solutions can be readily detected and monitored, signifying the potential application of such stable bone gelatin-CsSnCl 3 NCs in the development of fluorescence sensors and detectors.