Hydroxyl-driven construction of dual-emitting CsPbBr3/EuWO4(OH) composite for radiometric thermometer and information encryption applications

Self-assembled inorganic metal halide perovskite composites with high emitting efficiency, tunable multimode emission and stimuli-responsive luminescence demonstrated great potential in diversified luminescence applications. Here, a novel CsPbBr 3 /EuWO 4 (OH) composite was successfully prepared through the surface adsorption of Pb 2+ ions on hydroxylated EuWO 4 (OH) microsheets and subsequent nucleation of CsPbBr 3 peroviskite quantum dots (PQDs) by the anti-solvent crystallization in CsBr containing N,N-dimethylformamide (DMF) solution. Due to the distinct fluorescent thermochromic switching properties of temperature-insensitive Eu 3+ and sensitive CsPbBr 3 PQDs emitting centers, the resultant CsPbBr 3 /EuWO 4 (OH) composite exhibits excellent ratiometric temperature sensing performance. The CsPbBr 3 /EuWO 4 (OH) thermometer based on the fluorescence intensity ratio (FIR) technique originating from emissions of Eu 3+ to CsPbBr 3 PQDs was then explored with a high temperature sensitivity (S r ) of 5.8 % ℃ −1 at 54 ℃. In addition, a high-security-level information encryption scheme was proposed by utilizing the excitation-wavelength-dependent switchable fluorescence of CsPbBr 3 /EuWO 4 (OH) composite. This study provides a simple and feasible strategy for assembling dual-emission CsPbBr 3 /EuWO 4 (OH) composite, showing potential applications in optical ratiometric thermometry and information encryption fields.