Enhanced Photoelectrochemical Activity Realized from WS<sub>2</sub> Thin Films Prepared by RF‐Magnetron Sputtering for Water Splitting
Somnath Ladhane, Shruti Shah, Pratibha Shinde, Ashvini Punde, Ashish Waghmare, Yogesh Hase, Bharat Bade, Vidya Doiphode, Swati Rahane, Dhanashri Kale, Sachin R. Rondiya, Mohit Prasad, Shashikant P. Patole, Sandesh Jadkar
Abstract
Abstract We report the synthesis of tungsten sulfide (WS 2 ) films using RF‐magnetron sputtering at different RF powers. X‐ray diffraction (XRD) data confirm the hexagonal crystal structure of WS 2 with an average crystallite size of ∼44.54 Å. With increased RF power, the preferred orientation of WS 2 crystallites shifts from (002) to (100). Linear sweep voltammetry (LSV) was used to assess the Photoelectrochemical (PEC) activity of WS 2 films. The film deposited at 150 W demonstrated the highest photocurrent density of 5.44 mA/cm 2 . The 150 W film also showed a lower Tafel slope of ∼0.374 V/decade, indicating superior PEC activity. Mott Schottky's (MS) analysis revealed a notable shift in the flat band potential towards the negative side, suggesting a shifting of the Fermi level towards the conduction band. WS 2 film grown at 150 W demonstrated a majority charge carrier density of 6.2×10 21 cm −3 and a depletion layer width of 1.54 nm. The observed low charge transfer resistance of 155 Ω contributed to the enhanced PEC activity with a relaxation time constant of 37 ms. These properties suggest that WS 2 can be suitable for PEC water splitting.