Preparation And Characterization Of CdS And CdSe Semiconductor Nanoparticles

There are a lot of unsaturated dangling bonds, namely surface defect states, which will eventually influence the fluorescence quantum yields of nanoparticles on the surfaces of CdS and CdSe semiconductor nanoparticles. Up to now, a series of semiconductor nanoparticles with high photoluminecence intensity and quantum yields have been synthesized by using different surfactants which decreased the surface defects efficiently. In this paper, CdS and CdSe nanoparticles were synthesized in different reaction systems, moreover, the effects of reaction conditions and surfactants on the preparation processes and optical properties were systematically investigated.CdS and CdSe nanoparticles were synthesized in aqueous phase by using AOT (sodium bis(2-ethylehexyl)-sulfosuccinate) as surfactant, cadmium acetate as cadmium resource, thiourea as sulfer resource and NaSeSO3 as selenium resource respectively,. Through the characterization and analysis by use of UV-visible spectrophotometer, fluorescence spectrophotometer, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM), it was concluded that AOT had good surface modification to CdS and CdSe nanoparticles. Due to the amphiphilic properties of AOT, the synthesized CdS and CdSe nanoparticles can disperse in both polar and non-polar solvents.CdS, CdSe, MnS and Ag2S nanoparticles were synthesized on the interface of toluene and ethyle glycol (water) by the use of octadecylamine or sodium oleate as surfactants according to the principle of interface reactions. By virtue of UV-vis absorption spectrum, fluorescence spectra, XRD and TEM, it was suggested that the synthesized CdS and CdSe nanoparticles with small size and size distribution could give distinct quantum size effects.CdS and CdSe nanoparticles were synthesized by using sodium oleate as stabilizer, ethanol as solvent, cadmium acetaie and thiourea (NaHSe) as precursors, respectively. Through analysis of UV-visible absorption spectrum and fluorescent specra, it was found that CdS nanoparticles obtained at higher concentration (5mmol/L) and lower concentration (0.1mmol/L) showed different spectral characteristics. Characterized by XRD and TEM, it was proved that the synthesized CdS and CdSe nanoparticles with small size and size distribution had good dispersity and typical CdS and CdSe nanocrystalline structures.