Synthesis and characterization of transition metal doped ZnS nanocrystals for phosphor and photo-catalytic applications

Zn_1-xTM_xS [(TM: Fe or Ni); (0.00001 les x les 0.1)] nanocrystals have been synthesized using well known bottom-up synthesis technique; colloidal chemical coprecipitation method. Powder X-ray diffractometer and Transmission Electron Microscope (TEM) have been used for crystallographic and morphological characterization. Analysis of recorded broad X-ray diffraction patterns show zinc blende structured crystallites having average crystallite size ~3 nm. Average particle size calculated from the electron micrographs is in close agreement with the average crystallite size calculated from diffraction studies. Room temperature steady state luminescence spectra have been recorded for optical characterization. Detailed description about the radiative and non-radiative recombination mechanism dependence on the dopant concentration has been established from luminescence studies. Photo-catalytic properties of synthesized nanocrystals have been examined by degradation of methylene blue (MB) dye. Luminescence quantum efficiency and photo-catalytic behaviour dependence on the dopant concentration have been studied in detail.