| 1. |
- Domenech, Guillem, et al.
(author)
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Highly sensitive SnO2 nanowire network gas sensors
- 2023
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In: Sensors and actuators. B, Chemical. - : ELSEVIER SCIENCE SA. - 0925-4005 .- 1873-3077. ; 383
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Journal article (peer-reviewed)abstract
- In this work we present a methodology for the localized growth of nanowires on prespecified areas of micro -hotplates that allows to independently adjust the devices resistance and its response to the gas. This is achieved through the fabrication stripes containing the nanowires, with or without the presence of a gap in the stripe, giving rise that the nanowires bridge the current. The methodology is demonstrated growing SnO2 nanowire-based chemoresistors and the fabricated sensors have been characterized against CO and NO2. The results show the capability of tailoring nanowire stripe sizes from 1 to 100 mu m, including empty areas of the same sizes along the sensing material, and a response increase by a factor of up to 500. We attribute the response enhancement to the absence of nucleation seeds in the gap area, where only arching nanowires can allow the current to flow between electrodes. In this way, the current flow along the bridge of nanowires is restricted principally to the surface conduction, which is controlled by the interaction of the nanowires with gases.
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| 2. |
- Fan, Jiandong, et al.
(author)
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Enhanced Photovoltaic Performance of Nanowire Dye-Sensitized Solar Cells Based on Coaxial TiO2@TiO Heterostructures with a Cobalt(II/III) Redox Electrolyte
- 2013
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In: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 5:20, s. 9872-9877
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Journal article (peer-reviewed)abstract
- The growth of a TiO shell at the surface of TiO2 nanowires (NWs) allowed us to improve the power conversion efficiency of NW-based dye-sensitized solar cells (DSCs) by a factor 2.5. TiO2@TiO core-shell NWs were obtained by a two-step process: First, rutile-phase TiO2 NWs were hydrothermally grown. Second, a hongquiite-phase TiO shell was electrochemically deposited at the surface of the TiO2 NWs. Bare TiO2 and heterojunction TiO2@TiO NW-based DSCs were obtained using a cobalt(II/III) redox electrolyte and LEG4 as the dye. With this electrolyte/dye combination, DSCs with outstanding V-oc values above 900 mV were systematically obtained. While TiO2@TiO NW-based DSCs had slightly lower V-oc values than bare TiO2 NW-based DSCs, they provided 3-fold higher photocurrents, overall reaching 2.5-fold higher power conversion efficiencies. The higher photocurrents were associated with the larger surface roughness and an enhanced charge-carrier separation/transfer at the NW/dye interface.
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