Modification of Ag<sub>8</sub>SnS<sub>6</sub> Photoanodes with Incorporation of Zn Ions for Photo-Driven Hydrogen Production

oleh: Lin-Ya Yeh, Kong-Wei Cheng

Format: Article
Diterbitkan: MDPI AG 2021-03-01

Deskripsi

In this study, Zn ions were incorporated into Ag<sub>8</sub>SnS<sub>6</sub> thin films on glass and indium–tin–oxide-coated glass substrates using chemical bath deposition. Detailed procedures for the growth of Ag–Zn–Sn–S semiconductor films and their optical, physical and photoelectrochemical performances were investigated. X-ray diffraction patterns of samples revealed that kesterite Ag<sub>2</sub>ZnSnS<sub>4</sub> phase with a certain amount of Ag<sub>8</sub>SnS<sub>6</sub> phase can be obtained using ethylenediaminetetraacetic acid disodium salt and trisodium citrate as the chelating agent couples. Images of field-emission scanning electron microscope showed that plate-like microstructures with some spherical aggregates were observed for the sample at low Zn content. It changed to irregular spherical grains with the [Zn]/[Sn] ratios being higher than 0.95 in samples. The energy band gaps of the samples were in the range of 1.57–2.61 eV, depending on the [Zn]/[Sn] molar ratio in sample. From the Hall measurements, the carrier concentrations and mobilities of samples were in the ranges of 6.57 × 10<sup>12</sup>–1.76 × 10<sup>14</sup> cm<sup>−3</sup> and 7.14–39.22 cm<sup>2</sup>/V·s, respectively. All samples were n-type semiconductors. The maximum photoelectrochemical performance of sample was 1.38 mA/cm<sup>2</sup> in aqueous 0.25 M K<sub>2</sub>SO<sub>3</sub> and 0.35 M Na<sub>2</sub>S solutions.