Fe/Li Co-doped CuO: enhanced photosensing and conductivity correlated with structural modifications

Abstract

The photocatalytic and electronic properties of sol–gel-prepared divalent Fe3+ and Li+ co-doped monoclinic (c2/c) Cu0.945Fe0.055-xLixO powders were investigated. O-ions are in excess in Fe-rich samples, whereas O-vacancies (Vo) are prevalent in Li-rich samples due to the valence state differences between Fe3+ and Li+ ions. The bandgap remained largely unaffected, but lattice disorder increased with higher Li content. The electrical conductivity (σ) increased with increasing Li content. While the p-type nature decreased with increasing Li content, the electron mobility decreased with increasing Li content. The photocatalytic decomposition of harmful methylene blue (MB) dye was maximum for Cu0.945Fe0.0275Li0.0275O. For both Cu0.945Fe0.055O and Cu0.945Li0.055O, the degradation was lesser due to other physical processes, e.g., changes in the photocurrent. Light detection was faster in Fe-rich samples compared to pure and Li-rich samples. An attempt was made to form a heterojunction of ZnO/Cu0.945Fe0.014Li0.041O that exhibited significantly faster response times than their bulk counterparts for both pure and Li-rich samples. These findings highlight the potential of Cu0.945Fe0.055-xLixO samples and heterojunction configurations for enhanced photocatalytic and sensing applications. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.