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

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Low photoluminescence quantum yield (PLQY) of cesium lead chloride perovskite quantum dots (CsPbCl₃ PQDs) limits their use as ion detection probes.
• Developing probes with high sensitivity and selectivity is crucial for environmental and industrial monitoring.

Purpose of the Study:

• To enhance the PLQY of CsPbCl₃ PQDs via manganese (Mn) doping.
• To utilize Mn-doped CsPbCl₃ PQDs as luminescent probes for sensitive detection of Cu²⁺ ions and temperature.

Main Methods:

• Synthesis of CsPbCl₃:Mn PQDs using the hot injection method with varying Mn/Pb ratios.
• Characterization of synthesized PQDs, including PLQY measurements and optical property analysis.
• Application of CsPbCl₃:Mn PQDs as probes using the fluorescence intensity ratio (FIR) technique for Cu²⁺ detection and temperature sensing.

Main Results:

• Mn doping introduced a new emission band near 600 nm, significantly increasing PLQY by nearly tenfold (from 5.46% to 52.48%) at an optimal Mn/Pb ratio of 2.0.
• The FIR showed a linear response to Cu²⁺ concentration (22.12 nM–1600 nM) with a limit of detection of 22.12 nM, attributed to electron transfer quenching.
• CsPbCl₃:Mn PQDs demonstrated high relative sensitivity (15.89% K^-1 at 298 K) for temperature sensing with excellent reversibility.

Conclusions:

• Mn doping is an effective strategy to enhance the PLQY of CsPbCl₃ PQDs, enabling their use as sensitive luminescent probes.
• The developed CsPbCl₃:Mn PQDs show great promise for real-time monitoring of Cu²⁺ ions and temperature, with potential applications in engine oil analysis.