Synthesis and Characterization of Metal Doped Kesterite (Cu2ZnSnS/Se) Derived Nanostructures as Light Absorber for Thin Film Solar Cell Applications

Abstract

Kesterite materials (Cu2ZnSnS/Se or CZTS) exhibit encouraging potentials for energy conversion. In this study inexpensive, and cost-effective kesterite-derived nanostructures through metal doping in (CuZnXS, X=Ce, La, Mo) has been synthesized and test them as photo-absorbing materials for semiconductor-based thin film solar cell applications. The photo-absorbance or light-absorption propensity of the photo-anode material in a solar cell is essential to the overall effectiveness of the solar cell. By adding a second layer of photo absorbance material, the photo-anode activity can be increased, which may also increase the amount of photogenerated electrons. Optical spectroscopy methods, such as UV-visible spectroscopy, is used to examine the photo absorption characteristics of the synthesized nanostructures. The optical band gap, % transmittance, extinction coefficient and refractive index of the kesterite material has been calculated and it was found that the band gap of the as synthesized kesterite material is varies in the range 1.125eV -1.5eV which is suitable as the absorber material for solar cell applications. The structural defects and recombination centers are examined using Photoluminescence spectroscopy. X-ray diffraction (XRD) and Raman Spectroscopy has been done to study the structure parameters and vibrational modes of the as synthesized kesterite material. The XRD patterns of the materials shows the formation of kesterite material with tetragonal structure for Ce-CuZnS and Mo-CuZnS and kesterite with monoclinic structure for La-CuZnS. The Raman spectra of all samples shows the characteristics modes of Cu- xi S, Zn-S and Ce2O, La-O and different modes of S-Mo-S in Ce-CuZnS, La-CuZnS, and Mo-CuZnS respectively.