High-loading ultrastable CsPbBr3 perovskite quantum dots in hierarchical silicalite-1 by elimination of co-templates for multimodal optical applications

Abstract

All-inorganic CsPbBr₃ perovskite quantum dots (PQDs) show superior photophysical properties and great potential in various optoelectronic devices, but their low lattice formation energy and high delocalization of surface ions make them susceptible to ambient conditions. In this work, the hierarchical silicalite-1 zeolite co-templated by carbon nanotubes (CNTs) and tetrapropylammonium hydroxide (TPAOH) was applied to encapsulate CsPbBr₃ PQDs. Particularly, distinct nanosized CNTs, mass ratios of zeolite to CsPbBr₃, and thermal diffusion temperature were systematically studied to optimize the loading capacity and luminescence efficiency of CsPbBr₃ PQDs. Consequently, the micro-/mesoporous silicalite-1 confined CsPbBr₃ PQD nanocomposite obtained at 700 °C exhibited the best luminescence performance with a full-width at half-maximum (FWHM) of 25 nm, a high PLQY of ∼61.9% and an ultrahigh stability of >100 days in H₂O. The CsPbBr₃/silicalite-1 nanocomposite shows dual-mode temperature monitoring performance in terms of fluorescence emission intensity and spectral shift, rendering it a promising candidate for credible optical thermometry. Latent fingerprint identification and selective Fe³⁺ fluorescence sensing applicability of the CsPbBr₃/silicalite-1 nanocomposite were then developed. Also, a reversible off/on switching of the green fingerprint image under UV-light irradiation can be easily modulated by spraying Fe³⁺ aqueous solution and pure H₂O, respectively, achieving an effective anti-counterfeiting application.