Construction of Sb2S3/CdS/CdIn2S4 cascaded S-scheme heterojunction for improving photoelectrochemical performance

Antimony sulfide (Sb 2 S 3 ) 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 Sb 2 S 3 /CdIn 2 S 4 S-scheme heterojunction, we avoided the problem that electrons and holes cannot be separated and transported effectively due to many Sb 2 S 3 defects (more recombination centers), and improved its application in the field of photoelectrochemical water splitting. Meanwhile, in order to further improve the performance of Sb 2 S 3 /CdIn 2 S 4 photoelectrode, we introduced CdS energy platform between Sb 2 S 3 and CdIn 2 S 4 to form a Sb 2 S 3 /CdS/CdIn 2 S 4 cascaded S-scheme heterojunction. Compared with Sb 2 S 3 monomer, Sb 2 S 3 /CdS/CdIn 2 S 4 had higher absorbance intensity, IPCE value, ABPE value, and lower charge transfer resistance. In addition, the photocurrent density of the Sb 2 S 3 /CdS/CdIn 2 S 4 photoelectrode was about 4.20 mA/cm 2 (1.23 V vs. RHE), which was 1.3 times higher than that of the Sb 2 S 3 /CdIn 2 S 4 photoelectrode (3.29 mA/cm 2 ) and 3.2 times higher than that of monomer Sb 2 S 3 photoelectrode (1.32 mA/cm 2 ). This method offers new prospects for optimizing the performance of antimony chalcogenides photoelectrodes for photoelectrochemical water splitting.