CH₃I sensing using yttrium single atom-doped perovskite nanocrystals

Nanocrystals (NCs) of cesium lead halide perovskites are optically unstable, which prevents their use in optical sensors. The combination of perovskite NCs and metal single atoms (SAs) may be a good solution to this issue. Unfortunately, depositing metal SAs on perovskite NCs remains a challenge due to relative weak metal–halide bonds. Herein, we present that, via a photo assisted method using cesium lead halide perovskite NCs as host material to anchor Y single atoms, we successfully synthesize Y SA anchored CsPbBr₃ NCs (Y-SA/CsPbBr₃ NCs) with outstanding fluorescence stability through the formation of two Y–O bonds and two Y–Br bonds. In comparison to bare CsPbBr₃ NCs, Y-SA/CsPbBr₃ NCs possess more stable optical characteristics. The as-synthesized Y-SA/CsPbBr₃ NCs can be employed as a colorimetric platform to perform rapid CH₃I sensing. Detection limit of 0.044 ppm is exhibited in this approach with excellent anti-interference performance. The Y-SA/CsPbBr₃ NCs-based system has been applied to the detection of CH₃I in sweet potato samples with satisfying results.