Dual-emissive CsPbBr₃@NaGdF₄:Eu³⁺ nanocomposites for ratiometric temperature sensing and anti-counterfeiting...

Multi-emissive-center materials offer a powerful luminescent platform to overcome the constraints of single-component systems in advanced optical applications. Rational design of such materials enables tunable luminescence and improved functionality for temperature sensing and dynamic anti-counterfeiting. In this work, a dual-emissive nanocomposite, CsPbBr₃@NGF:Eu³⁺, was fabricated by integrating CsPbBr₃ perovskite quantum dots (PQDs) into highly porous NaGdF₄:Eu³⁺ nanoparticles, alleviating the poor light and thermal stability of CsPbBr₃ PQDs. Under 395 nm excitation, the nanocomposite exhibits distinct dual emissions originating from CsPbBr₃ PQDs (515 nm) and NaGdF₄:Eu³⁺ (615 nm). Leveraging their contrasting temperature-dependent fluorescence intensities, a fluorescence intensity ratio (FIR) temperature-sensing model was constructed, exhibiting outstanding performance from 293 to 393 K with an absolute sensitivity of 0.1735 K^-1 and a relative sensitivity of 4.1% K^-1. A temperature-driven dynamic anti-counterfeiting system with multi-level information encryption was further developed via reversible fluorescence color switching. This work provides promising materials for high-performance optical thermometry and a new strategy for intelligent anti-counterfeiting.