Preparation of Copper Antimony Sulfide Thin Film Solar Cells by Chemical Synthesis

Copper Antimony Sulfide (CuSbS₂) is a promising ternary semiconductor for use as an absorber layer in third-generation thin film heterojunction solar cells. This newly developed optoelectronic material offers a viable alternative to cadmium telluride (CdTe) and copper indium gallium di-selenide (Cu(In,Ga)Se₂) due to its composition of inexpensive, readily available, and non-toxic elements. These films were successfully produced at an optimal substrate temperature of 533 K using the conventional spray technique. X-ray diffraction and Raman studies confirm that the films exhibit a chalcostibite structure. Characterization studies reveal that the films possess lattice parameters of a = 0.60 nm, b = 0.38 nm, and c = 1.45 nm, with an absorption coefficient of 10⁵ cm^-1 and a band gap of 1.50 eV. Notably, the films exhibit p-type conductivity. All of these studies confirm that CuSbS₂ is an excellent choice for the absorber layer in solar cell applications. An attempt was made in this study to improve the crystallinity of the CuSbS₂ films by different experimental conditions. (i) CuSbS₂ films have been fabricated using two different carrier gases (air and nitrogen) via chemical spray pyrolytic technique. (ii) To enhance the crystallinity of these films, spray pyrolytic films have been kept on the hot plate at optimal substrate temperature for about 15 minutes. Subsequently, a CuSbS₂ solar cell is developed entirely through the non-vacuum method. The absorber layer is fabricated by using the spray pyrolytic method. A n-CdS buffer layer is successfully deposited via the chemical bath technique. The cell’s efficiency increased from 0.488% to 0.54% when the absorber layer in the solar cell was left on hot substrates for about 15 minutes following the pyrolytic reaction. The study discusses how these techniques contribute to improving the efficiency of the solar cell parameters.