Zhao Gaoling

The effect of the ratio of thiourea to Cd 2+ on the properties of CdS nanoparticles

CdS nanoparticles capped by thiourea and stabilized by PVP (poly N-vinyl-2-pyrrolidone) were prepared using a wet chemical route. The eventual particles size and size distribution can be systematically controlled by adjusting the relative ratios of thiourea to Cd2+. The nanoparticles were characterized by transmission electron microscopy (TEM), ultraviolet visible (UV-vis) absorption spectra and photoluminescence (PL) spectra. The results show that the higher thiourea/Cd2+ ratio leads to higher stability, smaller size and narrower size distribution. After the nanoparticles were capped by thiourea, the band emission of CdS nanoparticles can be observed in the PL spectra.

Preparation of CdS nanoparticles by hydrothermal method in microemulsion

CdS nanoparticles with good crystallinity were prepared by hydrothermal method in microemulsion composed of polyoxyethylene laurylether/water/cyclohexane/butanol. The structure and the size of the CdS nanoparticles were analyzed by TEM and XRD. The UV-Vis optical absorption of the samples was also investigated. The results show that hydrothermal treatment is an effective method to prepare CdS nanoparticles of hexagonal structure at lower temperature. The particles were in dimensional uniformity. The diameter of the CdS nanoparticles decreased with the increase of the molar ratio of water to surfactant. The minimum diameter of the CdS nanoparticles prepared in this work was about 10 nm. Obvious blue shift appeared in the UV-Vis absorption spectra.