AgSbS2 thin films produced by sulfurizing Sb/Ag stacks for photoelectrochemical applications

초록

In this work, the fabrication of AgSbS2 thin films by thermal evaporation of the Sb/Ag metallic layers and sulfurization at 350 degrees C for 30 min was reported. The influence of the Ag/Sb ratio (1.23 - 0.91) on the growth and properties of these films was investigated. The AgSbS2 films prepared with Ag-rich compositions (1.23 and 1.08) constituted an Ag3SbS3 secondary phase with a grain size of 1-6 mu m, a direct optical bandgap of 1.60 eV, and an electrical resistivity of 2.99-2.98x10(3) ohm cm. By decreasing the Ag/Sb ratio to stoichiometric proportion (1.01), the Ag3SbS3 secondary phase disappeared and phase pure AgSbS2 formed with improved grain size (3-8 mu m), bandgap energy (1.61 eV), and electrical resistivity (1.54x10(4) ohm cm). A further decrease in the Ag/Sb ratio to 0.91 (Ag-poor) resulted in the emergence of a monoclinic AgSbS2 phase and Ag3SbS3 secondary phase with a reduced grain size, increased bandgap (1.65 eV), and decreased electrical resistivity (7.13x10(3) ohm cm). The photoelectrochemical measurements (PEC) revealed a maximum photocurrent density of 4 mA/cm(2) at 1 V (vs. Hg/HgO) for the stoichiometric AgSbS2 film prepared with an Ag/Sb ratio of 1.01. In this study, it was revealed that the AgSbS2 films prepared by the two-stage process are suitable for efficient PEC water splitting.

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