| 초록 |
Coupling dissimilar oxides in heterostructures allows engineering of interfacial, optical, and charge separation properties of photoanodes for photoelectrochemical (PEC) water-splitting. Here, we demonstrate a double-heterojunction concept based on BiVO4/WO3/SnO2 triple-layer planar (TPH) photoanode, which shows simultaneous improvements in the charge transport and visible transmittance. Importantly, the WO3/SnO2 bottom-layer forms a disordered heterojunction, enabling intimate contact, lower interfacial resistance, and efficient charge separation/transport. In addition, the top BiVO4/WO3 heterojunction layer improves light absorption and charge separation. The resultant TPH photoanode shows greatly improved internal quantum efficiency and PEC performance. The PEC performance was further improved by a reactive-ion etching and CoOx deposition. Finally, we demonstrated a bias-free and stable solar water-splitting by constructing a tandem PEC device with a perovskite solar cell (~3.5 %). |
