Elaboration and optical properties of the ZnS nanocrystals embedded in polystyrene matrix

Synthesis of the nanoparticles has made great strides in the field of nanotechnologies particularly in optoelectronics. Reading information by lasers on solid supports, as example, is performed by wide gap semiconductor thin films. From fundamental research, several theories were proposed to explain the physical properties of this new class of materials. Zinc sulfide nanocrystals embedded in polystyrene matrix were successfully prepared by using spin coating method. The structural characterization was performed by X-ray diffraction. The ZnS nanocrystals are single crystals of wurtzite phase. The average diameter of the ZnS nanocrystals embedded in polystyrene is 10.47 nm. The room temperature UV-visible absorption spectra show a displacement towards of higher energies of the absorption edge. The room temperature luminescence is formed by five bands. The band at 385.88 nm is attributed to a band-to-band transition. The second at 408.22 nm is due to the transition of sulfide vacancies trap. The third at 441 nm is assigned to the surface sulfide vacancies, the band at 473.66 is due to the surface states and the last one situated at 524.95 is assigned to the donor-acceptor recombination. The spectroscopic and photoluminescence studies were also carried out and the results are discussed.