Optimization of the output parameters in kesterite-based solar cells by AMPS-1D

The presence of defects, grain boundaries and other impurities in Cu2ZnSnS4 (CZTS) thin film material is detrimental on output performances of fabricated solar cells. Moreover the formation of non stable and high resistance contacts to CZTS contribute also to lower the values of short circuit density (Jsc), open circuit voltage (Foc), fill factor (FF) and therefore the efficiency of thin film solar cells. This study evaluates the baseline ZnO/CdS/CZTS cell structure using AMPS-1D program and quantifies reasons for the efficiency limits predicted in such a device. The effect of back contact material, acceptor concentration as well as the absorber thickness on CZTS cell performance is also studied. The solar cell with a back contact work function of 5.6 eV, an acceptor concentration of 4×1015cm-3 and an absorber layer´s thickness of 2250 nm showed the best performance with a conversion efficiency of 15.68%. This presented work is essential because it can contribute to fully understand the performance of CZTS solar cell and to fabricate cells with a precise control of the process parameters with a reduced surface as well as bulk recombination and secondary phases.