Tailoring the photoelectrochemical water splitting of CuSbS2 thin films by artificial defect engineering based on Bi doping

In this work, an environmentally friendly and economic one-step electrodeposition technique was used to synthesize Bi-doped CuSbS2 (CAS) thin films for photoelectrochemical (PEC) water-splitting applications. An experimental study was performed on undoped and doped samples by tuning the concentrations of bismuth nitrate (Bi (NO3)3), as Bi-doped precursor. The physical properties of the synthesized CAS thin films have been examined by various tools after annealing treatment. The X-ray diffraction measurements indicate that the incorporation of bismuth Bi ions into (CAS) films does not lead to any discernible impact on the orthorhombic crystal structure or phase purity. The Raman spectra demonstrated dual mode behaviors observed at 250 cm(-1) and 450 cm(-1) with modifications in peak positions about 5 cm(-1) discerned in response to variations in Bi doping levels. By means of scanning electron microscopy measurements, it is found that the average particle size increases with increasing Bi doping level, which decreases the grain boundary carrier recombination while diminishing the surface roughness of the CAS films. However, the optical band gap decreased, as the doping levels increased from 0 to 15 at.% Bi. Through the PEC measurements, the highest current density of - 5.2 mA cm(-2) at 0 V versus RHE has been observed for the film subject of optimized Bi doping level (10 at.% Bi), which is approximately tenfold higher than that of the undoped one. Besides, a considerable negative shift in the onset potential could reach 0.48 V versus RHE. Finally, the stability tests were investigated for all the photoelectrodes at 0 V versus RHE and revealed that the photocurrent density could be obtained under chopped illumination for 200 min.