Optimization: a proposed pathway to overcome the impasse of low efficiency in CZTS thin-film photovoltaics

The quest to improve the performance of copper zinc tin sulfide (CZTS) thin-film photovoltaics has been increasing recently. This pursuit is driven by the optimal direct bandgap, non-toxic, and abundant constituent elements of CZTS. In this work, a novel CZTS thin-film solar cell with FTO/AZO/CdS/CZTS/MoS 2 /Mo device structure has been numerically modeled and simulated with SCAPS-1D software. This modeled structure was achieved from a combination of different optimization processes, which involves the window layer, absorber layer, and the back interface of the device. Simulation of this device gave a promising optimized result with a conversion efficiency of 26.19%, a fill factor of 62.07%, a short-circuit current of 27.56 mA cm −2 , and an open-circuit voltage of 0.94 V. Further studies from the Mott–Schottky slope showed that the average carrier concentration obtained from the C – V calculations is ~ 5.2 × 10 16 cm −3 . The simulation processes provide an essential guideline for the fabrication of highly efficient CZTS thin-film solar cell.