Systematic study of an Fe2O3 stacked homojunction photoelectrochemical photoelectrode

In this study, iron (III) oxide (Fe2O3) homojunction photoelectrodes were grown via the hotplate chemical bath deposition method. Various Fe2O3 homojunction-structured photoelectrodes have been proposed to overcome the problems such as low carrier mobility, high electron-hole recombination rate and defects due to lattice mismatch suffered by heterojunction photoelectrodes or single-layer photoelectrodes. The effects of the buffer layer, the number of stacked layers, the stacked-layer structure, and the thermal annealing treatment process on the Fe2O3 homojunction photoelectrode were systematically investigated. As a result, the Fe2O3 homojunction photoelectrode with a total of four Fe2O3 stacked thin films showed the best photoelectrochemical performance and was the thickest herein; it also had the highest X-ray diffraction (XRD) peak intensity for the (110) plane, the lowest XRD full-width at half maximum (FWHM), the highest donor density values, and the lowest resistance between the photoelectrode and electrolyte. This Fe2O3 homojunction photoelectrode with four stacked thin films showed the highest photocurrent density herein (0.54 mA/cm(2) at 1.64 V-RHE), which is an approximately 160% improvement over the value of the single-layer Fe2O3 photoelectrode.