Two-step in situ synthesis of CsPbX3@TS-1 zeolite (X = Cl, Br, I) nanocomposites for optical thermometric, latent fingerprints and anti-counterfeiting applications

Abstract

All-inorganic CsPbX₃ (X = Cl, Br and I) nanocrystals (NCs) receive great attention for their multi-functional applications. Here, we propose a facile two-step in situ strategy to encapsulate CsPbX₃ (X = Cl, Br and I) NCs in the interrupted structure of the hierarchical titanium silicate-1 (TS-1) molecular sieve, which involves the Cs⁺-TPA⁺ (tetrapropylammonium ion) ion exchange process and a subsequent solution reaction with a PbX₂-containing organic solution to afford the formation of highly stable luminescent CsPbX₃-TS nanocomposites. Interestingly, the as-obtained CsPbBr₃-TS nanocomposite exhibits remarkable dual-mode temperature-readout optical thermometric properties involving a linear response in the fluorescence intensity and a blue-shift of the CsPbBr₃ emission. The CsPbBr₃-TS composite also demonstrates excellent luminescent stability in various polar solvents, while the fluorescence color of CsPbCl₃-TS, CsPbCl_1.5Br_1.5-TS, CsPbBr_1.5I_1.5-TS, and CsPbBrI₂-TS nanocomposites turn to blue (410–420 nm) when exposed to strongly polar molecules of acetone, ethanol, and water, ascribing to the hydrogen bonding effect between the surface –NH₂ group in CsPbX₃ and carbonyl (–CO) and hydroxyl (–OH) groups contained in solvents. The space confinement and various stabilities of CsPbX₃ (X = Cl, Br and I)-TS nanocomposites afford them great potential in multi-functional application fields, including temperature sensing, fingerprint identification, anti-counterfeiting and security protection.