Enhancement in photoluminescence emission in the UV-visible region from chemically synthesized silver doped ZnS nanoparticles

摘要

Nanoparticles of ZnS:Ag doped with Ag~+ (0.5%) and capped with polyvinyl pyrolidone (PVP) have been synthesized by chemical co-precipitation method. The particle size of the synthesized sample is ~2.5 nm as obtained from the analyses of X-ray diffraction (XRD) pattern and high resolution transmission electron microscope (HRTEM) image of the sample. The optical absorption and photoluminescence (PL) emission properties are measured by using UV-visible spectrophotometer and PL spectrometer, respectively. The quantum confinement effect is demonstrated by the blue shift in the bandgap of the sample. The Gaussian fittings of the measured room-temperature PL spectrum shows the presence of six emission bands centered at 356.5, 393, 449, 483, 508, and 526 nm. However, the intensity of the emission band at 394 nm in ZnS:Ag sample is the strongest and it is -60 times more intense than that of the PL emission intensity obtained in an undoped ZnS sample.