V2O5/WO3 Mixed Oxide Films as pH-EGFET Sensor: Sequential Re-Usage and Fabrication Volume Analysis

V2O5/WO3 Mixed Oxide Films as pH-EGFET Sensor: Sequential Re-Usage and Fabrication Volume Analysis

Author Guidelli, Eder Jose Google Scholar
Guerra, Elidia Maria Autor UNIFESP Google Scholar
Mulato, Marcelo Google Scholar
Institution Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Abstract A vanadium and tungsten mixed oxide was deposited onto glassy carbon substrates and used as pH sensor in extended gate field effect transistor (EGFET) devices. WO3 at a molar ratio of about 5% was mixed with V2O5 by means of the sol-gel method. the main focus of this investigation was to determine the operation conditions for the best response of the device and to propose the mechanism involved in the sensor response. the use of either original or reused films were employed and the importance of the total volume of the starting solution was also examined. the time response of the V2O5/WO3-pH-EGFET sensor is due to a deprotonation mechanism of vanadium and tungsten oxide, similarly to a discharging capacitor. the loss of protons by the oxide film depends on the time it remains immersed in the buffer solution and this process is accelerated upon raising the pH value. the increase of the films fabrication volume reduces the importance of the changes of the surface charges compared to the charges of the bulk, leading to less sensitive and less stable sensor response. Therefore, the smaller the amount of material used, the better the sensing properties of the device. (C) 2012 the Electrochemical Society. All rights reserved.
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Date 2012-01-01
Published in Ecs Journal of Solid State Science and Technology. Pennington: Electrochemical Soc Inc, v. 1, n. 3, p. N39-N44, 2012.
ISSN 2162-8769 (Sherpa/Romeo, impact factor)
Publisher Electrochemical Soc Inc
Extent N39-N44
Origin http://dx.doi.org/10.1149/2.007203jss
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000319446200002
URI http://repositorio.unifesp.br/handle/11600/34364

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