A Spatially Separated Organic–Inorganic Hybrid Photoelectrochemical Cell for Unassisted Overall Water Splitting

Abstract

The Z-scheme overall solar water splitting is a mimic of natural photosynthesis to convert solar energy into chemical fuels. Despite much effort, the available Z-scheme artificial systems are still rare, and most of them rely on inorganic semiconductors. In this study, inspired by the characteristics of p-type and higher unoccupied molecular orbital level of organic semiconductors, a spatially separated organic–inorganic hybrid Z-schematic photoelectrochemical (PEC) cell for unassisted overall water splitting is developed by wiring inorganic ZnO nanorod arrays photoanode and organic poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid (P3HT:PCBM) photocathode in a tandem manner. In the short-circuit configuration, the photocurrent density reaches an initial value of ∼78 μA cm–2 and an average value of ∼95 μA cm–2 under continuous UV–vis light irradiation, giving rise to the solar-to-fuel conversion efficiency of ∼0.12%. The average gas evolution rates are 1.59 μmol h–1 for H2 and 0.75 μmol h–1 for O2 unde...