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  Jia, L.; Bogdanoff, P.; Ramirez-Caro, A.; Bloeck, U.; Stellmach, D.; Fiechter, S.: Fe₂O₃ Porous Film with Single Grain Layer for Photoelectrochemical Water Oxidation: Reducing of Grain Boundary Effect. Advanced Materials Interfaces 3 (2016), p. 1500434/1-7

10.1002/admi.201500434

Abstract:
In this study, a promising alternative method for addressing grain boundary issues in hematite (α-Fe2O3)-based photoanodes is presented. The porous α-Fe2O3 films are prepared by dip coating a polymerizable precursor onto fluorine-doped tin oxide (FTO) substrates. The photoelectrochemical (PEC) performance of α-Fe2O3 photoanodes is characterized and optimized through controlling the annealing temperature and the number of deposition cycles. Samples of improved crystallinity consisting of a layer of hematite particles of 50 nm in diameter exhibit highest photoresponses of 1.04 mA cm−2 at 1.23 V versus a reversible hydrogen electrode (RHE), and 2.0 mA cm−2 before the dark current onset at 1.7 VRHE. This study indicates that the PEC performance of hematite can be enhanced greatly by an improved crystallinity, particle texture, and a better control of grain boundary effects.