Production and characterization of Sb2S3 absorber layer for photovoltaic applications

CuInGaSe2, CdTe, and Cu2ZnSnS4 are semiconductor materials commonly used as absorber layers in photovoltaic solar cell applications. Compared to these materials, Sb2S3 film, which consists of non-toxic elements, has drawn attention in scientific research due to its long-term stability, low raw material cost, and high absorption coefficient. However, the efficiency values of Sb2S3-based solar cells are lower than the theoretically predicted value. The theoretical and experimental studies in the literature are insufficient in identifying the factors causing this limitation. These evaluations have motivated the production and detailed analysis of Sb2S3 films which is a promising material for future applications. To address the deficiencies observed in the literature regarding Sb2S3 films and to solve the highlighted problems, Sb2S3 precursor coatings were first obtained using the resistive thermal evaporation method. Subsequently, the production and optimization of Sb2S3 films were carried out through thermal processes performed at different temperatures, atmospheres, and gas flow rates. The structural, optical, surface, and electrical properties of the obtained Sb2S3 films were investigated using methods such as energy dispersive x-ray spectroscopy (EDX), x-ray diffraction (XRD), Raman spectroscopy, UV-VIS spectroscopy, Atomic Force Microscopy (AFM), and two-probe technique. It was observed that Sb2S3 films can be obtained without any secondary phase through the applied thermal processes, the optical bandgap value can be reduced to 1.7 eV, the sulfur problem frequently emphasized in the literature can be addressed through the sulfurization process performed in the borosilicate cell designed for thermal processes, and the surface morphologies of Sb2S3 films can be modified. However, despite all the optimization efforts, it was revealed that the electrical resistivity values could not be reduced to the desired level. As a result of the studies conducted within the scope of this thesis work, detailed analyses were carried out for the optimization of Sb2S3 films, which are particularly promising materials in energy applications. The outputs, especially the method used in the sulfurization process, are believed to provide guidance for future potential research.