eprintid: 1546806 rev_number: 43 eprint_status: archive userid: 608 dir: disk0/01/54/68/06 datestamp: 2017-04-01 08:20:23 lastmod: 2021-12-13 02:44:43 status_changed: 2017-04-25 15:45:53 type: article metadata_visibility: show creators_name: Kafizas, A creators_name: Francas, L creators_name: Sotelo-Vazquez, C creators_name: Ling, M creators_name: Li, Y creators_name: Glover, E creators_name: McCafferty, L creators_name: Blackman, C creators_name: Darr, J creators_name: Parkin, I title: Optimizing the Activity of Nanoneedle Structured WO3 Photoanodes for Solar Water Splitting: Direct Synthesis via Chemical Vapor Deposition ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F56 note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: Solar water splitting is a promising solution for the renewable production of hydrogen as an energy vector. To date, complex or patterned photoelectrodes have shown the highest water splitting efficiencies, but lack scalable routes for commercial scale-up. In this article, we report a direct and scalable chemical vapor deposition (CVD) route at atmospheric pressure, for a single step fabrication of complex nanoneedle structured WO3 photoanodes. Using a systematic approach, the nanostructure was engineered to find the conditions that result in optimal water splitting. The nanostructured materials adopted a monoclinic γ-WO3 structure and were highly oriented in the (002) plane, with the nanoneedle structures stacking perpendicular to the FTO substrate. The WO3 photoanode that showed the highest water splitting activity was composed of a ∼300 nm seed layer of flat WO3 with a ∼5 μm thick top layer of WO3 nanoneedles. At 1.23 VRHE, this material showed incident photon-to-current efficiencies in the range ∼35–45% in the UV region (250–375 nm) and an overall solar predicted photocurrent of 1.24 mA·cm–2 (∼25% of the theoretical maximum for WO3). When coupled in tandem with a photovoltaic device containing a methylammonium lead iodide perovskite, a solar-to-hydrogen efficiency of ca. 1% for a complete unassisted water splitting device is predicted. date: 2017-03-23 date_type: published publisher: AMER CHEMICAL SOC official_url: http://dx.doi.org/10.1021/acs.jpcc.7b00533 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green article_type_text: Article verified: verified_manual elements_id: 1276643 doi: 10.1021/acs.jpcc.7b00533 lyricists_name: Blackman, Christopher lyricists_name: Darr, Jawwad lyricists_name: Glover, Emily lyricists_name: Li, Yaomin lyricists_name: Ling, Min lyricists_name: McCafferty, Liam lyricists_name: Parkin, Ivan lyricists_name: Sotelo-Vazquez, Carlos lyricists_id: CBLAC43 lyricists_id: JDARR17 lyricists_id: ENKGL52 lyricists_id: YLIDX67 lyricists_id: MLING88 lyricists_id: LMCCA06 lyricists_id: IPPAR53 lyricists_id: SOTEL29 actors_name: Flynn, Bernadette actors_id: BFFLY94 actors_role: owner full_text_status: public publication: Journal of Physical Chemistry C volume: 121 number: 11 pagerange: 5983-5993 pages: 11 issn: 1932-7447 citation: Kafizas, A; Francas, L; Sotelo-Vazquez, C; Ling, M; Li, Y; Glover, E; McCafferty, L; ... Parkin, I; + view all <#> Kafizas, A; Francas, L; Sotelo-Vazquez, C; Ling, M; Li, Y; Glover, E; McCafferty, L; Blackman, C; Darr, J; Parkin, I; - view fewer <#> (2017) Optimizing the Activity of Nanoneedle Structured WO3 Photoanodes for Solar Water Splitting: Direct Synthesis via Chemical Vapor Deposition. Journal of Physical Chemistry C , 121 (11) pp. 5983-5993. 10.1021/acs.jpcc.7b00533 <https://doi.org/10.1021/acs.jpcc.7b00533>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1546806/1/Kafizaz_Optimizing_Activity_Nanoneedle.pdf