摘要
Photocatalytic splitting of water under solar light has proved itself to be a promising approach toward the utilization of solar energy and the generation of environmentally friendly fuel in a form of hydrogen. In this work, we demonstrate highly efficient solar-to-hydrogen conversion efficiency of 7.7% by photovoltaic–photoelectrochemical (PV–PEC) device based on hybrid MAPbI perovskite PV cell and WO /BiVO core–shell nanorods PEC cell tandem that utilizes spectral splitting approach. Although BiVO is characterized by intrinsically high recombination rate of photogenerated carriers, this is not an issue for WO /BiVO core–shell nanorods, where highly conductive WO cores are combined with extremely thin absorber BiVO shell layer. Since the BiVO layer is thinner than the characteristic carrier diffusion length, the photogenerated charge carriers are separated at the WO /BiVO heterojunction before their recombination. Also, such architecture provides sufficient optical thickness even for extremely thin BiVO layer due to efficient light trapping in the core–shell WO /BiVO nanorods with high aspect ratio. We also demonstrate that the concept of fill factor can be used to compare I–V characteristics of different photoanodes regarding their optimization for PV/PEC tandem devices.