Low-lead CsPbBr3 quantum dot glass with Eu/Pb-ratio-tunable dual emission for optical temperature sensing and anti-counterfeiting

Essential Role of Eu 3+ in low-lead CsPbBr 3 QD glass. • Tunable Green-to-Red Emission via Eu/Pb Ratio. • Eu 3+ induced lattice contraction and PL blue shift. • Optical temperature sensing based on dual emission. CsPbBr 3 perovskite quantum dots (QDs) have garnered considerable attention owing to their outstanding optical properties. However, their practical applications are hindered by poor stability and the toxicity of lead, whereas lead-free alternatives often compromise optical performance. In this study, Eu 3 + -incorporated low-lead CsPbBr 3 QDs embedded in borosilicate glass were successfully fabricated via melt quenching and heat treatment. The molar fraction of PbBr 2 in the glass system is as low as 0.0367–0.0612%, corresponding to a lead reduction of approximately 97% compared with conventional CsPbBr 3 QD glasses. We demonstrate that Eu 3+ ions are essential for the precipitation of CsPbBr 3 QDs under low-lead conditions. Meanwhile, Eu 3+ provides red emission, thereby creating dual emission centers. The green-to-red emission ratio can be finely tuned by varying the Eu/Pb ratio. In addition, Eu 3+ substitution for Pb 2+ induces lattice contraction, which causes a blue shift of the emission peak of CsPbBr 3 QDs. Temperature-dependent photoluminescence (PL) spectra of the Eu0.6 Pb0.08 sample reveal that the fluorescence intensity ratio (FIR) increases monotonically with increasing temperature from 100 to 300 K, with maximum absolute and relative sensitivities of 3.77 × 10 −2 K −1 and 5.55 × 10 −1 K −1 , respectively. This work demonstrates the potential of low-lead perovskite QD glasses for optical temperature sensing.