SYNTHESIS AND PROPERTIES OF CU2ZNSNS4 AND RELATED MATERIALS

Abstract

Copper zinc tin sulfide (Cu2ZnSnS4, abbr. CZTS) has attracted considerable attention as a promising absorber in solar cells. It has been reported that the constraints on forming stoichiometric CZTS are very strict. Even though CZTS has been prepared by using various physical vacuum methods and solution-based methods, expensive high vacuum technology and high annealing temperatures (above 500 °C) are used in physical vacuum methods and secondary phases present in CZTS prepared by the solution-based methods. In this thesis, two simple and cost-effective methods were explored to prepare CZTS. One method was solid-state reaction of nanocrystalline binary sulfides in sulfur environment. These binary sulfides were synthesized by chemical bath deposition. Another method was a mechanochemical process (MCP) through ball milling of elemental Cu, Zn, Sn, and S materials. A systematic study of structural, optical, and electronic properties of CTZS through various techniques has been done. A photovoltaic device based on CZTS/TiO2 was fabricated to demonstrate its photovoltaic behavior.