Fabrication of Indium-doped n-Fe_2O_3 Thin Films by Spray Pyrolytic Deposition Method for Photoelectrochemical Water Splitting

摘要

Stable indium-doped n-Fe2O_3 thin films were fabricated using a spray pyrolytic deposition (SPD) method on conducting indium-doped, tin oxide coated, glass substrates. The highest photocurrent density of 3.61 mA/cm~2 was observed at +0.3 V vs. SCE for indium-doped n-Fe2Oj samples prepared at an optimum substrate temperature of 688 K. The corresponding highest photoconversion efficiency of 3.73 % was found for the SPD samples prepared using optimum spray time of 60 seconds. X-ray diffraction (XRD) results showed mixed structures (a-Fe_2O_3 and InFeO3). A bandgap energy of 2.2 eV was found from UV-Vis absorption data, which was found to be closer to the indirect bandgap of 2.1 eV obtained from photocurrent densities obtained under monochromatic light illumination. Both of these bandgaps are in agreement with the known bandgap of Fe2O_3. XRD and XPS data confirm the presence of indium dopant on the surface of the thin films in the form of indium(m) iron (ill) oxide (InFeO_3) confirming the successful synthesis of indium-doped n-Fe2O_3.