Characterization of Cu2ZnSnS4 thin films deposited by one-step thermal evaporation for a third generation solar cell

In this study, one-step thermal evaporation was employed for the fabrication of phase-pure CZTS thin films on glass substrates from single crystalline Cu-poor ingot grown by Bridgman technique. Structural analyses revealed the formation of a mono-phase CZTS kesterite structure for the thin films annealed at 450 degrees C under N-2 atmosphere. The AFM measurements demonstrated significant morphological changes in films with increasing the annealing temperature from 200 degrees C to 450 degrees C, supporting the results obtained via XRD and Raman studies. From the optical measurements, the band gap was estimated to be 1.47 eV for the CZTS film annealed at 450 degrees C, which is close to the optimum value required for photovoltaic applications. As a device application of the optimized CZTS thin films, an attempt was made to construct a TiO2 NRs based and CdS-free FTO/TiO2 NRs/CZTS/Ag superstrate CZTS solar cells. TiO2 NRs were grown by hydrothermal technique, which offers a simple and a cost-effective route for large-scale production of one-dimensional nanostructures. The solar cell exhibited an open-circuit voltage of 0.35 V, a short-circuit current density of 7.28 mA/cm(2), a fill factor of 23.9% and a power conversion efficiency of 0.61%, the highest efficiency recorded so far for a single-dimensional TiO2 nanostructures based superstrate CZTS solar cell. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

In this study, phase-pure CZTS thin films were successfully fabricated on glass substrates using one-step thermal evaporation technique. The optimized CZTS thin films showed a band gap of 1.47 eV and were utilized to construct a TiO2 NRs based solar cell with a record efficiency of 0.61%.