Alqahtani, M;
Sathasivam, S;
Chen, L;
Jurczak, P;
Piron, R;
Levallois, C;
Letoublon, A;
... Parkin, IP; + view all
(2019)
Photoelectrochemical water oxidation of GaP1-xSbx with a direct band gap of 1.65 eV for full spectrum solar energy harvesting.
Sustainable Energy & Fuels
, 3
(7)
pp. 1720-1729.
10.1039/c9se00113a.
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Abstract
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%.
| Type: | Article |
|---|---|
| Title: | Photoelectrochemical water oxidation of GaP1-xSbx with a direct band gap of 1.65 eV for full spectrum solar energy harvesting |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1039/c9se00113a |
| Publisher version: | https://doi.org/10.1039/c9se00113a |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| Keywords: | Science & Technology, Physical Sciences, Technology, Chemistry, Physical, Energy & Fuels, Materials Science, Multidisciplinary, Chemistry, Materials Science, SEMICONDUCTORS, PHOTOANODES, PHOTOLYSIS, SI |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10078666 |
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