Effect of sintering optimization on the photoelectrochemical performance of Cu2ZnSnS4 nanocrystal films

BACKGROUND: Semiconductor-based photoelectrochemical (PEC) water splitting represents one attractive route to generate clean hydrogen. Cu2ZnSnS4 (CZTS) is considered a promising photoelectric material for PEC water splitting due to its high absorption coefficient, small bandgap, nontoxicity, and earth-abundant elements. Only a few critical parameters limit the performance of CZTS nanocrystal films. Of those, heat treatment is essential for producing high-performance films. RESULTS: In this work, CZTS nanocrystals were produced by a facile method and applied in making CZTS films for PEC water reduction. Therefore, the influences of heat treatment parameters on the performance of films were investigated in the low-temperature heat treatment range. The surfactant polyvinylpyrrolidone (PVP) in the films could not be completely decomposed at low heat treatment temperatures, leading to film resistance that was harmful to the PEC process. Meanwhile, SnSx impurities would arise at temperatures over 400 ?, thus reducing the PEC performance. CONCLUSION: The best activity for PEC water reduction was obtained at 385 ? for 10 min. Furthermore, the PEC performance of CZTS films generated by fast heating (10 ? s(-1)) was superior to that of films generated by slow heating (10 ? min(-1)) due to the inhibition from the development of SnSx impurities. (c) 2022 Society of Chemical Industry (SCI).

Automated summary

This study investigates the influence of heat treatment on the performance of CZTS nanocrystal films for PEC water reduction. It is found that at low temperatures, the surfactant PVP in the films cannot be completely decomposed, leading to increased film resistance and hindered PEC process. At high temperatures, SnSx impurities are generated, which reduces the PEC performance. The best PEC water reduction activity is achieved at 385℃ for 10 minutes.