CdSe Quantum Dots Supported on Sb₂S₃ Nanorods as S-Scheme Heterojunction Photoanode in Photoelectrochemical Cells

Abstract

The narrow bandgap semiconductor Sb 2 S 3 has been extensively utilized in solar cells for its impressive light absorption coefficient and carrier mobility. However, a large number of deep energy defects provide carrier recombination sites that limit its photoelectrochemical (PEC) performance. In this study, Sb 2 S 3 nanorods (NRs) and CdSe quantum dots (QDs) were successfully prepared, and Sb 2 S 3 /CdSe-annealed quasi-one-dimensional heterojunction photoanodes with the S-scheme were constructed. The Sb 2 S 3 /CdSe-annealed composite photoelectrode achieves a 12 times increase in photocurrent density compared to the 0.4 mA cm −2 of the Sb 2 S 3 photoelectrode. Overall, the synergistic effect of the [hk1]-oriented Sb 2 S 3 NRs and the S-scheme heterojunction promotes carrier transport, achieving a spatial separation of photogenerated carriers and efficiently weakening the recombination of the electron−hole pair. This study provides a simple method for the low-cost development of Sb 2 S 3 NRs with [hk1] orientation and an idea to enhance its development in the PEC water splitting direction.