CuSbS2-based thin film solar cells prepared from electrodeposited metallic stacks composed of Cu and Sb layers

Polycrystalline copper antimony sulfide (CuSbS₂) films were fabricated by sulfurization of electrodeposited metallic stacks of Cu and Sb layers with various Cu/Sb atomic ratios at 450 °C in H₂S (5% in Ar). Structural analyses using X-ray diffraction revealed that CuSbS₂ films obtained from Cu-poor and Cu-rich metallic stacks (Cu/Sb = 0.7 and 1.3) contained impurity phases, whereas single-phase CuSbS₂ film was formed from the stoichiometric stack (Cu/Sb = 1). Morphological studies using SEM indicated that adherence of thus-formed CuSbS₂ films to the Mo substrate was dependent on the precursor composition: a CuSbS₂ film with poor adherence having many crevices was formed when the Cu-rich metallic stack was used, while CuSbS₂ films with good adherences were obtained when Cu-poor and stoichiometric metallic stacks were used. Performance of solar cells with an Al:ZnO/CdS/CuSbS₂/Mo structure also depended on structural characteristics of these CuSbS₂ films, i.e., a preliminary conversion efficiency of ca. 3% was obtained for device based on the CuSbS₂ film obtained from the stoichiometric metallic stack, whereas the devices derived from Cu-poor and Cu-rich metallic stacks showed the conversion efficiency less than 1%.