Ecofriendly and low cost CZTS absorber layer deposited by sol-gel for solar cell applications: Effect of copper concentration on physical properties

Abstract Copper zinc tin sulfide (CZTS) thin films have been deposited by spin coating technique at various copper concentration ranging from 0.5M to 2.5M. The XRD patterns show the existence of the three main characteristic peaks of CZTS (112), (220) and (312), which indicate the formation of the kesterite structure of CZTS. Gap energy was calculated based on the derivation method using the absorbance data, and the values obtained vary from 1.46 eV to 1.58 eV depending on the copper molarities. Hall effect measurements were used to determine the conductivity, which in turn increased with the concentration of copper in the films. The results showed that the C3=1.5M exhibits higher crystallinity and better optical performance among the others. Finally, a theoretical efficiency of 11.6% was obtained by injecting the solar cell (CZTS/ZnS/S:ZnO) in SCAPS1D using the parameters obtained in this study. Under the adopted synthesis conditions, the theoretical simulation corroborated the experimental findings thus confirming that the synthesized material is a promising candidate for solar cell applications as an absorber layer.