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

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 CdTe and 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 these studies confirm that CuSbS2 as an absorber layer is highly suitable for 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 fabricated entirely through chemical synthesis methods, with the absorber layer deposited using spray pyrolysis. A CdS buffer layer is successfully deposited via chemical bath deposition. The efficiency of the cell has been improved from 0.488% to 0.54% when the absorber films are kept on the hot substrates for about 15 min after the completion of the pyrolytic reaction. The study discusses how these techniques contribute to improving the efficiency of the solar cell parameters.