A review on chemical bath deposition of metal chalcogenide thin films for heterojunction solar cells

Heterojunction (HJ) thin-film II–VI solar cells are emergent substitutes to the traditional silicon solar cells because of improved efficiency and cost-effectiveness. A renewed interest in depositing the constituent layers employing chemical bath deposition (CBD) is shown because of the absence of any stringent reaction conditions which ensures the preservation of the properties of the constituent layers. Variation in the growth conditions has strong effects on the morphologies and the properties of the resultant films specially the interface. Inappropriate or alloyed interfaces may result in pinholes formation affecting the resultant electric field because of reduced junction area and enhanced recombination for carriers which in turn affects the efficiency. In this review, we provide an overview of the different combinations of metal chalcogenide/chalcopyrite thin-film layers for HJ solar cells by CBD and achieving control over the resultant morphology, particularly focusing on interfacial epitaxial relationship which is found to have substantial influence on the efficiency of the resultant cell. Graphical abstract: Heterojunction (HJ) thin-film II–VI solar cells are emergent substitutes to the traditional silicon solar cells because of improved efficiency and cost-effectiveness. A renewed interest in depositing the constituent layers employing chemical bath deposition (CBD) is shown because of its simplicity and versatility. Variation in the growth conditions like temperature and the reagent concentrations have strong effects on the morphologies and the properties of the resultant films specially the interface. In this review, we provide an overview of the different combinations of metal chalcogenide/ chalcopyrite thin-film layers for HJ solar cells by CBD and achieving control over the resultant morphology and phase composition, particularly focusing on interfacial epitaxial relationship, which is found to have substantial influence on the efficiency of the resultant cell. [Figure not available: see fulltext.].