Structural, Optical and Ionic Properties of PVA Capped CuS Quantum Dots

Copper sulphide quantum dots were synthesized by a simple chemical route using ammonia (aq.) as a complexing agent in polyvinyl alcohol (PVA) matrix. Copper acetate monohydrate and thiourea were used as precursors. The particle sizes as obtained from X-Ray diffraction (XRD) results were found to be in good agreement with those of high-resolution transmission electron microscopy (HRTEM). The ultraviolet-visible (UV-Vis.) absorption and photoluminescence (PL) emission spectra exhibited a systematic blue shift of absorption and emission respectively confirming the quantum confinement effect in the synthesized quantum dots. The band gap as estimated from Tauc-plot increased from 3.26eV to 3.92eV with a change in the concentration of the complexing agent. The fluorescence transmission infra-red (FTIR) spectra exhibited Cu-S stretching peaks characteristic of CuS. Ionic contributions of the electrolytic ionic CuS solution as measured by a standard conductivity cell clearly showed the semiconducting behavior of the product material. The synthesized material may be exploited in the fabrication of an optoelectronic device in the UV-blue region.