Synthesis of highly stable double-coated Zn-doped cesium lead bromide nanocrystals for indium ion detection in water

Abstract

Cesium lead halide (CsPbX₃: X = I, Br, Cl) perovskite nanocrystals (NCs) have proven their potential as a contender for various optoelectronic applications. They have also been used as fluorescent probes for the detection of different metal ions. However, perovskite NCs are prone to degradation by water, light, and heat. Therefore, it is essential to tackle these issues before implementing them in real-world applications. Recently, doping metal ions in perovskite structures and core/shell nanostructure formation are some of the strategies that have been implemented to improve NC stability, which is still not satisfactory. To further enhance NC stability, we grew a polyvinylpyrrolidone (PVP) polymer shell around pre-synthesized silica-coated Zn-doped CsPbBr₃ NCs, which demonstrated better stability against water and heat and less effectiveness in the halide exchange process. The optimized polymer shell around the NCs revealed the highest stability with improved emission intensity. The as-synthesized NCs were green emitters and showed maximum photoluminescence quantum yield (PLQY) up to 88%. The water and heat stability of the double-coated Zn-doped CsPbBr₃ NCs were increased by about two times compared with those of the silica-coated NCs. To the best of our knowledge, there are no reports to date on indium (In) ion detection using perovskite NCs as the fluorescent probe. Here, double-coated perovskite NCs were tested as a fluorescent probe for In ion detection in water. These observations are incredibly beneficial for lighting applications and can be used for In-ion detection in natural resources and industrial wastes.