Large-Grained Cu2BaSnS4 Films for Photocathodes

p-Type compounds Cu2BaSnS4 (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.