Porous Cu2BaSn(S,Se)4 Film as a Photocathode Using Non-Toxic Solvent and a Ball-Milling Approach

OpenAlex İngilizce

Cu 2 BaSn(S,Se) 4 (CBTSSe) has been proposed as an alternative to Cu 2 ZnSn(S,Se) 4 (CZTSSe) for solar absorbers due to its reduced propensity for antisite disorder and band tailing while maintaining the desirable characteristics of band gap tunability, earth-abundance, and low toxicity constituent metals. However, current film deposition methods require high-vacuum conditions or toxic solvents, which are less desirable features for prospective large-scale production. In this paper, ball milling is demonstrated as a route toward a scalable processing method for CBTSSe, using a precursor ink consisting of common elements Cu 2 S, BaS, Sn, and S in low-toxicity ethanol. A final film with a thickness and average grain size on the order of 1 μm was synthesized with a band gap of 1.56 eV, corresponding to a Cu 2 BaSnS 4– x Se x ( x ≈ 3) stoichiometry. A porous CBTSSe photocathode with Pt/TiO 2 /CdS overlayers was fabricated to demonstrate the photocurrent-generating capabilities of the film, yielding current densities as high as 5.54 mA/cm 2 at 0 V versus a reversible hydrogen electrode (V/RHE).