Construction of SbS/CdS/CdInS cascaded S-scheme heterojunction for improving photoelectrochemical performance.

Antimony sulfide (SbS) is a relatively abundant and environmentally friendly emerging photovoltaic material, which has been gradually applied in solar cells and photocatalysis. It has high light absorption capacity, but it suffers many deep-level defects and is prone to recombination of electron-hole pairs within itself. Here, by constructing the SbS/CdInS S-scheme heterojunction, we avoided the problem that electrons and holes cannot be separated and transported effectively due to many SbS defects (more recombination centers), and improved its application in the field of photoelectrochemical water splitting. Meanwhile, in order to further improve the performance of SbS/CdInS photoelectrode, we introduced CdS energy platform between SbS and CdInS to form a SbS/CdS/CdInS cascaded S-scheme heterojunction. Compared with SbS monomer, SbS/CdS/CdInS had higher absorbance intensity, IPCE value, ABPE value, and lower charge transfer resistance. In addition, the photocurrent density of the SbS/CdS/CdInS photoelectrode was about 4.20 mA/cm (1.23 V vs. RHE), which was 1.3 times higher than that of the SbS/CdInS photoelectrode (3.29 mA/cm) and 3.2 times higher than that of monomer SbS photoelectrode (1.32 mA/cm). This method offers new prospects for optimizing the performance of antimony chalcogenides photoelectrodes for photoelectrochemical water splitting.