Bi₂Se₃/WSe₂ heterojunction for enhanced photoelectrochemical water splitting

We report magnetron-sputtering-grown Bi₂Se₃/WSe₂ heterojunction on thin tungsten (W) metal foil towards photoelectrochemical (PEC) water-splitting application. The crystalline and structural quality of prepared heterojunction was examined by X-ray diffraction and Raman spectroscopy. The X-ray photoelectron spectroscopy confirmed the chemical composition of Bi₂Se₃/WSe₂. The PEC measurements were performed in 0.5 M Na₂SO₄ electrolyte solution under simulated sunlight (AM = 1.5 G) conditions. The PEC measurements showed the improved photocurrent density of Bi₂Se₃/WSe₂ with an obtained photocurrent density of ~ 205 µA/cm², which is 2.7 times higher compared to bare WSe₂. The enhanced photocurrent density of Bi₂Se₃/WSe₂ could be attributed to the creation of additional active sites, as well as type-II band alignment between Bi₂Se₃ and WSe₂ which helps easy separation of the photogenerated electron and hole pair by reducing charge recombination.

The Bi₂Se₃/WSe₂ heterojunction was grown on flexible W metal foil using large area chemical vapor deposition and magnetron sputtering techniques. This innovative heterojunction enhances charge separation and light absorption, leading to improved PEC efficiency. The findings of this work could inspire further research into layered heterojunction, potentially unlocking new pathways for efficient energy conversion technologies.

The Bi₂Se₃/WSe₂ heterojunction grown on thin metal foils enhanced the PEC performance for the generation of solar hydrogen fuel.