Development of Quantum Dots Nanosensors for Heavy Metals Detection

Abstract

This study demonstrates the potential application of polyethyleneimine (PEI)-modified quantum dots for sensing heavy metals, specifically copper ions, in aqueous matrices. Quantum dots were synthesized in aqueous phase, revealing a spherical morphology, a size of less than 5 nm, and a face-centered cubic crystalline structure. The presence of PEI on the quantum dots' surface significantly enhanced their photoluminescence within the range of 400 nm to 650 nm. To assess the sensor capabilities of PEI-capped quantum dots, two copper precursors (CuSO4 and CuNO3) were utilized at concentrations ranging from 0 ppm to 38 ppm. A systematic decrease in fluorescence intensity with increasing copper concentration was observed, establishing a quantitative relationship. These findings underscore the potential of PEI-modified quantum dots as efficient and selective sensors for copper ions. The concentration-dependent response in fluorescence intensity reflects the sensitivity of the system, suggesting promising applications in the field of heavy metal detection.