Mn-doped CsPbCl3 perovskite quantum dots: A dual-function probe for copper detection and temperature sensing

The low photoluminescence quantum yield (PLQY) of CsPbCl 3 perovskite quantum dots (PQDs) poses a significant challenge to their application as ion detection probes. To address this issue, we enhanced the PLQY of CsPbCl 3 PQDs through Mn doping. These enhanced PQDs were then employed as probes for the highly sensitive detection of Cu 2+ ions and temperature. CsPbCl 3 :Mn PQDs with varying Mn/Pb ratios were synthesized via hot injection. The Mn doping introduced an emission band near 600 nm, with intensity increasing alongside doping concentration. At an Mn/Pb ratio of 2.0, the PLQY was enhanced nearly tenfold, from 5.46 % for undoped CsPbCl 3 to 52.48 % for CsPbCl 3 :Mn. CsPbCl 3 :Mn PQDs with the highest PLQY were employed as luminescent probes, utilizing the fluorescence intensity ratio (FIR) technique for copper detection and temperature sensing. The experimental results demonstrated a linear relationship between the FIR and Cu 2+ concentration over the range of 22.12 nM–1600 nM, with 22.12 nM being the calculated limit of detection. Analysis of the emission spectra and fluorescence lifetimes at varying Cu 2+ concentrations revealed that electron transfer from CsPbCl 3 to Cu 2+ induced fluorescence quenching. CsPbCl 3 :Mn exhibits a high relative sensitivity of 15.89 % K −1 at 298 K, along with excellent reversibility. These findings highlight the potential application of CsPbCl 3 :Mn PQDs in both temperature sensing and the analysis of wear metals in engine lubricating oils.