Monday, 30 January, 2017

Dual absorber Fe2O3/WO3 host-guest architectures for improved charge generation and transfer in photoelectrochemical applications

A. Muller, I. Kondofersky, A. Folger, D. Fattakhova-Rohlfing, T. Bein and C. Scheu -
Materials Research Express, 10.1088/2053-1591/aa570f (2017)

In this study the influence of the spatial distribution and of different nanostructures of WO₃ and Fe₂O₃ in the dual absorber system Fe₂O₃/WO₃ was systematically investigated for the first time. WO₃ was applied as a scaffold and/or as a surface treatment to mesoporous Fe₂O₃ films. Both approaches strongly increased the performance compared to the individual photoabsorbers. By combining a host guest architecture with a surface treatment, current densities of about 0.7 mA cm⁻² at 1.23 V versus reversible hydrogen electrode under AM 1.5 illumination with an incident photon-to-current efficiency of 17% at 350 nm were achieved without the use of further catalysts. We could identify several beneficial interactions between Fe₂O₃ and WO₃. WO₃ strongly scatters visible light, resulting in increased absorption by Fe₂O₃ and higher current densities. We also determined a cathodic shift in the onset potential to 0.8 V and increased transfer rates of up to 88%. This combination of beneficial effects proves the viability of the presented device architecture.

Article on journal´s webpage