Facile fabrication of P-type hematite thin film and application for enhanced photoelectrochemical oxygen evolution reaction efficiency

Oxygen evolution reaction (OER), the counter reaction of hydrogen evolution reaction (HER) in solar water splitting, is rate determining step of whole reaction due to its low reaction kinetics and high overpotential. To enhance overall solar water splitting reaction kinetics, both n-type and p-type hematite (alpha-Fe2O3) transparent thin film was fabricated by doping Ti for n-type hematite and Zn for p-type hematite, respectively, by facile deposition and annealing (DA) method. Ti doped n-type hematite film showed enhanced photocurrent density compared with pure hematite thin film (from 0.26 mA/cm2 to 0.57 mA/cm2). In case of Zn doped p-type he-matite film showed 3.610 x 1016 cm-3 of hole concentration calculated by Mott-Shottky equation. Finally, by applying thin Zn doped p-type hematite layer on Ti doped n-type hematite thin film, n-p junction hematite film was fabricated. The synthesized n-p junction hematite showed remarkable OER efficiency with 0.90 mA/cm2 of photocurrent density at 1.23 V vs. RHE with 0.3 V of onset potential decrease in OER reaction, compared with Ti doped n-type hematite thin film. This study suggests the facile and effective ways to apply p-type hematite thin film to increase photoelectrochemical water splitting efficiency by enhancing OER efficiency.

Automated summary

By doping titanium and zinc, n-type and p-type hematite transparent thin films were fabricated to enhance the kinetics of solar water splitting and increase the efficiency of oxygen evolution reaction (OER).