Straightforward encapsulation of ultrastable CsPbBr ₃ PQDs and rare-earth emitters in zeolite for ratiometric temperature sensing and wet fingerprint recognition

All-inorganic metal halide perovskite quantum dot (PQD) hybrids with high stability, multi-model emission and responsive luminescence are of great importance for optical applications. Herein, a dual-emitting CsPbBr₃/Si-1:Eu³⁺ composite was successfully prepared by simultaneous encapsulation of CsPbBr₃ PQDs and EuBr₃ through a one-step thermal diffusion method. Partial destruction of the five-membered rings in silicalite-1 (Si-1) zeolite resulted from the PbBr₂ etching effect at high temperatures that enhances the bonding formation between Eu³⁺ and Si-OH, leading to the grafting of Eu³⁺ onto the Si-1 zeolite framework. The strongly confined CsPbBr₃ PQDs in CsPbBr₃/Si-1:Eu³⁺ exhibit an ultrastable green emission over 30 days of soaking in water. In particular, the CsPbBr₃ PQDs and red-light Eu³⁺ emission center display distinct thermal quenching behaviors at elevated temperatures. So the CsPbBr₃/Si-1:Eu³⁺ composite can serve as an effective ratiometric thermometer using the fluorescence intensity ratio (FIR) technique, showing a high sensitivity of 3.4% °C^-1 at 54 °C and a temperature resolution of less than 0.2 °C in the range of 20-100 °C. The water-stable CsPbBr₃/Si-1:Eu³⁺ composite is also suitable for wet fingerprint recognition. This work introduces a straightforward method for preparing dual-emissive CsPbBr₃/Si-1:Eu³⁺ composites for multimodal applications.