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Photoelectrochemical water oxidation of GaP 1−x Sb x with a direct band gap of 1.65 eV for full spectrum solar energy harvesting
- Source :
- Sustainable Energy & Fuels, Sustainable Energy & Fuels, Royal Society of Chemistry, 2019, 3 (7), pp.1720-1729. ⟨10.1039/C9SE00113A⟩, Sustainable Energy & Fuels, 2019, 3 (7), pp.1720-1729. ⟨10.1039/C9SE00113A⟩
- Publication Year :
- 2019
- Publisher :
- HAL CCSD, 2019.
-
Abstract
- International audience; Hydrogen produced using artificial photosynthesis, i.e. solar splitting of water, is a promising energy alternative to fossil fuels. Efficient solar water splitting demands a suitable band gap to absorb near full spectrum solar energy and a photoelectrode that is stable in strongly alkaline or acidic electrolytes. In this work, we demonstrate for the first time, a perfectly relaxed GaP0.67Sb0.33 monocrystalline alloy grown on a silicon substrate with a direct band gap of 1.65 eV by molecular beam epitaxy (MBE) without any evidence of chemical disorder. Under one Sun illumination, the GaP0.67Sb0.33 photoanode with a 20 nm TiO2 protective layer and 8 nm Ni co-catalyst layer shows a photocurrent density of 4.82 mA cm−2 at 1.23 V and an onset potential of 0.35 V versus the reversible hydrogen electrode (RHE) in 1.0 M KOH (pH = 14) aqueous solution. The photoanode yields an incident-photon-to-current efficiency (IPCE) of 67.1% over the visible range between wavelengths 400 nm to 650 nm. Moreover, the GaP0.67Sb0.33 photoanode was stable over 5 h without degradation of the photocurrent under strong alkaline conditions under continuous illumination at 1 V versus RHE. Importantly, the direct integration of the 1.65 eV GaP0.67 Sb0.33 on 1.1 eV silicon may pave the way for an ideal tandem photoelectrochemical system with a theoretical solar to hydrogen efficiency of 27%.
- Subjects :
- Photocurrent
Silicon
Renewable Energy, Sustainability and the Environment
business.industry
Band gap
Energy Engineering and Power Technology
chemistry.chemical_element
02 engineering and technology
010402 general chemistry
021001 nanoscience & nanotechnology
Solar energy
7. Clean energy
01 natural sciences
0104 chemical sciences
Artificial photosynthesis
[SPI.MAT]Engineering Sciences [physics]/Materials
Monocrystalline silicon
Fuel Technology
chemistry
[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic
Optoelectronics
Reversible hydrogen electrode
Direct and indirect band gaps
0210 nano-technology
business
Subjects
Details
- Language :
- English
- ISSN :
- 23984902
- Database :
- OpenAIRE
- Journal :
- Sustainable Energy & Fuels, Sustainable Energy & Fuels, Royal Society of Chemistry, 2019, 3 (7), pp.1720-1729. ⟨10.1039/C9SE00113A⟩, Sustainable Energy & Fuels, 2019, 3 (7), pp.1720-1729. ⟨10.1039/C9SE00113A⟩
- Accession number :
- edsair.doi.dedup.....32e6b7b61b35773d51c7a1d445668279