Synthesis and Characterization of an Earth-Abundant Cu₂BaSn(S,Se)₄ Chalcogenide for Photoelectrochemical Cell Application.

Cu₂BaSnS_4-xSe_x films consisting of earth-abundant metals have been examined for photocathode application. Films with different Se contents (i.e., Cu₂BaSnS_4-xSe_x with x ≤ 2.4) were synthesized using a cosputter system with post-deposition sulfurization/selenization annealing treatments. Each film adopts a trigonal P3₁ crystal structure, with progressively larger lattice constants and with band gaps shifting from 2.0 to 1.6 eV, as more Se substitutes for S in the parent compound Cu₂BaSnS₄. Given the suitable bandgap and earth-abundant elements, the Cu₂BaSnS_4-xSe_x films were studied as prospective photocathodes for water splitting. Greater than 6 mA/cm² was obtained under illumination at -0.4 V versus reversible hydrogen electrode for Pt/Cu₂BaSnS_4-xSe_x films with ∼60% Se content (i.e., x = 2.4), whereas a bare Cu₂BaSnS_4-xSe_x (x = 2.4) film yielded ∼3 mA/cm² at -0.4 V/RHE.

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Author Jeffrey Glass Electrical and Computer Engineering

Author David Mitzi Thomas Lord Department of Mechanical Engineering and Materia ...