Large-Grained Cu₂BaSnS₄ Films for Photocathodes

Abstract

p-Type compounds Cu 2 BaSnS 4 (CBTS) are extremely attractive materials for photocathode applications because of their suitable conduction and valence bands, earth-abundant sources, and environmental friendly nature. Herein, an inexpensive and reproducible aqueous solution approach has been developed to synthesize CBTS films with single-crystalline grains as large as micron scale. Because of the large crystalline grains, the as-grown CBTS films show excellent carrier mobility (1.29 cm 2 /V·s). Greater than 4 mA·cm –2 photocurrent density has been obtained in a neutral solution for bare Mo/CBTS film photocathodes under 100 mW·cm –2 illumination at 0 V versus reversible hydrogen electrode.