Spray pyrolysed Cu2ZnSnS4 thin film photovoltaic cell fabricated using cost effective materials

Abstract

The kesterite Cu2ZnSnS4 (CZTS) absorber material was prepared using 2-methoxyethanol solvent without formation of any secondary phases and the same was confirmed using Glancing Incidence X-Ray Diffraction and Raman studies. The surface analysis was carried out by Field Emission Scanning Electron Microscopy and Atomic Force Microscope and the thickness of the deposited films was calculated using FIB-SEM analysis. The precursor concentration of CZTS with 2:1:1:10 exhibits Cu-poor and Zn-rich CZTS film were achieved via sulfurization-free approach and was confirmed by EDX analysis. The optical absorbance, transmittance and bandgap of the films were characterized by UV–Visible spectrometer. The fluorescence spectroscopy was used to detect the electronic structural defects of the films and Hall measurements revealed that the prepared CZTS film exhibits p-type semiconductor behavior. As an attempt towards the preparation of nontoxic and low cost fabrication, the superstrate device structure glass/FTO/ZnO/ZnS/CZTS/Al was deposited using earth abundant materials in a cost effective method. The photovoltaic response was attained with a short circuit current density of 5.6 μA cm−2, open circuit voltage of 307 mV. The interface quality and internal charge transfer resistance of the CZTS device were investigated using Electrochemical Impedance Spectroscopy.