Enhanced Photoresponse of Solution-Processed Copper Tetrathiovandate (Cu ₃ VS ₄ ): Toward Efficient Nanostructured Photovoltaics

Multinary chalcogenide semiconductors are emerging as compelling candidates for next-generation optoelectronics. The present study focuses on the fabrication and photoelectrochemical evaluation of sulvanite, copper tetrathiovandate (Cu3VS4) nanocrystal (NC) films as potential photovoltaic (PV) absorber materials. Cu3VS4 is a semiconductor (1.0−1.7 eV) with a theoretically determined high hole carrier mobility, and featuring an intermediate band gap, thus also representing a strong candidate for efficient charge transport material in PV applications. In this work, Cu3VS4 was synthesized through a hot-injection method, leading to NCs with an average particle size of ∼26.6 nm, subsequently processed into stable colloidal dispersions for thin-film deposition. Cu3VS4 films exhibited a p-type behavior observed from the reduced photocurrent densities in chronoamperometry as measured in an aqueous Eu3+/Eu2+ redox electrolyte media. Under 1 sun illumination conditions, the films show a change in the photocurrent density of 131 μA cm−2. The charge-transfer and reaction kinetics were evaluated using electrochemical impedance spectroscopy and Tafel polarization curves. This work demonstrates photocurrent generation from Cu3VS4 thin films, highlighting the material’s promise for future application in solution-processed PV devices.