Surface Ferroelectric Polarization Promotion on Photoelectrochemical Oxygen Evolution by Transparent P(VDF-TrFE)

Abstract Acquiring remarkable light absorption and efficient charge carriers’ separation and migration are critical to highly-efficient photoelectrochemical (PEC) water splitting. However, fast recombination of excitons in bulk electrode materials is still the major challenge for current PEC photoelectrodes deployment. Introducing effective electric field across the interface by ferroelectric polarization holds great promise for anisotropic charge separation. Herein, we present a nano-thick transparent ferroelectric P(VDF-TrFE) film on semiconducting TiO2 as a model ferroelectric-PEC hybrid. The positively polarizing of TiO2/P(VDF-TrFE) effectively enhance the photocurrent density 186% and 570% compared to that of non-polarized and negatively polarized cases. Such improvement is ascribed to the separation of photogenerated carriers associated with the work function variations of the P(VDF-TrFE) film under polarization, inducing the band re-alignment at the TiO2/P(VDF-TrFE) interface. This concept provides a novel approach for optimizing the catalytic characteristics of TiO2 and can be extended to other transparent and flexible systems.