Earth-Abundant Orthorhombic BaCu2Sn(SexS1-x)4 (x ≈ 0.83) Thin Film for Solar Energy Conversion

Exploiting renewable solar energy in terms of solar driven water splitting and photovoltaic devices provides clean and efficient paths to overcome diminishing fossil fuel resources and the greenhouse effect. Here, a state-of-the-art earth-abundant BaCu2Sn-(Se0.83S0.17)(4) (BCTSSe) thin film has been presented as a promising top-cell absorber in tandem photoelectrochemical water splitting and photovoltaic conversion devices. Our BCTSSe thin film exhibits a direct bandgap of 1.85 eV with strong optical absorption coefficients (a > 10(4) cm(-1)). Without extensive interface and electrode optimization, our best BCTS photoelectrochemical cell showed a photocurrent of 5 mA cm(-2) at 0 V vs reversible hydrogen electrode. Moreover, our best-performing BCTSSe prototype photovoltaic cell with a configuration of fluorine-doped SnO2 (FTO, back contact)/BCTSSe/CdS/ZnO/alurninum doped ZnO (AZO, front contact) has achieved an efficiency of 1.57%.