We report facile solution processing of mesoporous hematite (α-Fe2O3) thin films for high efficiency solar-driven water splitting. Fe2O3 thin films were prepared on fluorine doped tin oxide(FTO) conducting substrates by spin coating of a precursor solution followed by annealing at 550 oC for 30 min. in air ambient. Specifically, the precursor solution was prepared by dissolving non-toxic FeCl3 as an Fe source in highly versatile dimethyl sulfoxide(DMSO) as a solvent. The as-deposited and annealed thin films were characterized for their morphological, structural and optical properties using field-emission scanning electron microscopy(FE-SEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and UV-Vis absorption spectroscopy. The photoelectrochemical performance of the precursor (α-FeOOH) and annealed (α-Fe2O3) films were characterized and it was found that the α-Fe2O3 film exhibited an increased photocurrent density of ~0.78 mA/cm2 at 1.23 V vs. RHE, which is about 3.4 times higher than that of the α-FeOOH films (0.23 mA/cm2 at 1.23 V vs. RHE). The improved performance can be attributed to the improved crystallinity and porosity of α-Fe2O3 thin films after annealing treatment at higher temperatures. Detailed electrical characterization was further carried out to elucidate the enhanced PEC performance of α-Fe2O3 thin films.

• Mahesh P. Suryawanshi(Optoelectronic Convergence Research Center, Department of Material Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea)
• Seonghyeop Kim(R & D Division, Feelstone Inc., 37 Eco-gil, Damyang-eup, Damyang-gun, Jeollanam-do 517-700, Republic of Korea)
• Uma V. Ghorpade(Optoelectronic Convergence Research Center, Department of Material Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea)
• Umesh P. Suryawanshi(Optoelectronic Convergence Research Center, Department of Material Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea)
• Jun Sung Jang(Optoelectronic Convergence Research Center, Department of Material Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea)
• Myeng Gil Gang(Optoelectronic Convergence Research Center, Department of Material Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea)
• Jin Hyeok Kim(Optoelectronic Convergence Research Center, Department of Material Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea) Corresponding author
• Jong Ha Moon(Optoelectronic Convergence Research Center, Department of Material Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea) Corresponding author