Photoluminescence characteristics of ZnS:Cu nanoparticles

ZnS:Cu nanoparticles were synthesized by hydrothermal process. New luminescence characteristics were observed with the copper concentration from 0 to 2at.%. The room-temperature photoluminescence emission spectra (PLE) of ZnS:Cu nanoparticles showed five luminescence peaks using 310 nm line of laser as excitation source. The peaks at 398, 423 and 445 similar to 458 nm and those at 488 and 530 nm can be attributed respectively to the splitting of the blue and green luminescence bands due to the introduction of new energy levels of the Cu cation. And the different luminescence origins were discussed. The structure and morphology of samples were studied by XRD and TEM, respectively. The results reveal a cubic structure of ZnS. UV-Vis optical absorption spectra show peaks centered at about 320 nm. The blue shift can be attributed to the quantum confinement effect of the ZnS:Cu nanostructures.