Synthesis and characterization of CZTS films

ABSTRACT Multilayerfilms with kesterite are often used for energy conversion, such as photoanode for hydrogen production and manufacture of photovoltaic solar cells. It is due to the fact that they are efficient and use small amounts of material. Cu2ZnSnS4, known as CZTS, is a semiconductor belonging to the kesterite group, which can be obtained in powder or film form. Copper, zinc, tin and sulfide are precursors commonly used in the synthesis of the CZTS. The methodology used to synthesize films is crucial for the success of the final product. It is essential to develop methods which can lower synthesis costs, which can also lower the solar cell costs, for example. Besides the costs, the method must be efficient and increase the efficiency of the devices in which they are employed, and must not be harmful to the environment. This study developed a methodology to synthesize CZTS. It was used in this work dimethyl sulfoxide, copper acetate, tin chloride, zinc chloride and thiourea as precursors. The layers of the film above the glass substrate were characterized with X-ray diffraction, ultraviolet and visible analyses, scanning electron microscopy, fourier transform infrared spectroscopy and X-ray fluorescence spectroscopy. The results absorbance peaks between 300 and 400 nm, in the ultraviolet range, reflectance around 40% in the visible, transmittance reaching above 50% and 50%, and direct band gap about 1.42 ± 0.02 eV associated with the kesterite. The characterization methods proved to be efficient to identify the presence of the kesterite phase at films produced by overlapping layers.