Effects of Urea as an Additive in Fe 2 O 3 Thin-Film Photoelectrodes

In this study, an Fe 2 O 3 photoelectrode was grown on a fluorine-doped tin oxide substrate via microwave chemical bath deposition. We added various amounts of urea as an additive to the FeCl 3 precursor for the fabrication of the Fe 2 O 3 photoelectrode and investigated the effects of the concentration of the urea additive on the morphological, optical, structural, electrical, and photoelectrochemical properties of this photoelectrode. Among the different concentrations evaluated, the maximum photocurrent density (0.51 mA/cm 2 at 0.6 V vs. SCE) was obtained using 0.05 M urea, as the resulting electrode had the greatest thickness, highest flat-band potential, and preferential growth along the (110) plane along with favorable electron transport characteristics. The maximum photocurrent density of the sample prepared with 0.05 M urea was approximately 60% greater than that obtained from the sample prepared in the absence of urea. This study showed that the photoelectrochemical properties of the Fe 2 O 3 photoelectrode were substantially influenced by the changes in the morphological, optical, structural, and electrical properties caused by the addition of urea. Graphic Abstract