Figure 1: Haematite with radically improved turn-on characteristics.
From: Enabling unassisted solar water splitting by iron oxide and silicon
(a) Steady-state current density-potential behaviours of various haematite photoelectrodes. The current densities of Si photocathode placed behind the haematite photoanode are shown to illustrate the meeting points. (b) Band diagram of unmodified haematite (grey) and NiFeOx-decorated haematite after re-growth treatments (red) under flat-band, quasi-equilibrium conditions. The Fermi level shift (denoted as 1) is a direct result of the re-growth treatment. The hole quasi-equilibrium potential shift (denoted as 2) is due to the application of NiFeOx. (c) Open circuit potential measurements of aH, sdH, rgH I, rgH II, rgH III and NiFeOx-decorated rgH II under 8-sun (red, triangle), 1-sun (blue, square) and dark (black, circle) conditions. Throughout this manuscript, sdH refers to solution-derived haematite; rgH I, rgH II, and rgH III denote haematite samples subjected to the regrowth treatments one, two and three times, respectively. Haematite prepared by atomic layer deposition (ALD) and then annealed at 500 °C and 800 °C are labelled aH and aH 800, respectively. NiFeOx/rgH II represent rgH II haematite decorated with amorphous NiFeOx catalysts. The error bars were obtained by taking s.d. values of measurements on at least three different samples for each data point.
