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

Antimony sulfide (Sb2S3) 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 Sb2S3/CdIn2S4 S-scheme heterojunction, we avoided the problem that electrons and holes cannot be separated and transported effectively due to many Sb2S3 defects (more recombination centers), and improved its application in the field of photoelectrochemical water splitting. Meanwhile, in order to further improve the performance of Sb2S3/CdIn2S4 photoelectrode, we introduced CdS energy platform between Sb2S3 and CdIn2S4 to form a Sb2S3/CdS/CdIn2S4 cascaded S-scheme heterojunction. Compared with Sb2S3 monomer, Sb2S3/CdS/CdIn2S4 had higher absorbance intensity, IPCE value, ABPE value, and lower charge transfer resistance. In addition, the photocurrent density of the Sb2S3/CdS/CdIn2S4 photoelectrode was about 4.20 mA/cm2 (1.23 V vs. RHE), which was 1.3 times higher than that of the Sb2S3/CdIn2S4 photoelectrode (3.29 mA/cm2) and 3.2 times higher than that of monomer Sb2S3 photoelectrode (1.32 mA/cm2). This method offers new prospects for optimizing the performance of antimony chalcogenides photoelectrodes for photoelectrochemical water splitting.