Preparation of Sn-doped CuAlS2 films with an intermediate band and wide-spectrum solar response

As a member of Cu-containing chalcopyrites, CuAlS2 is a promising candidate material for intermediate band solar cells (IBSCs). In this paper, the intermediate band mechanism of Sn doped CuAlS2 was investigated both theoretically and experimentally, and the two sub-bandgaps were measured to be 1.91 eV and 1.31 eV, respectively. A novel and convenient method of Electrophoretic Deposition (EPD) was utilized to prepare Sn doped CuAlS2 films. Due to the wide-spectrum of absorption introduced by the intermediate band, Sn doped CuAlS2 films showed better photoelectrochemical performance (PEC).