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
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DOI：
10.1149/2.007203jss
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发表时间：
2012-01-01
影响因子：
2.2
通讯作者：
Mulato, Marcelo
中科院分区：
文献类型：
--
作者：
Guidelli, Eder Jose;Guerra, Elidia Maria;Mulato, Marcelo
在玻碳衬底上沉积了钒钨混合氧化物，并将其用作扩展栅场效应晶体管(EGFET)器件的pH传感器。采用溶胶-凝胶法将摩尔比约为5%的WO_3与V_2O_5混合。本研究的主要目的是确定装置最佳响应的操作条件，并提出传感器响应所涉及的机理。使用原始或重复使用的胶片，也检查了起始溶液的总体积的重要性。V_2O_5/WO_3-pH-EGFET传感器的时间响应是由于钒和氧化钨的去质子化机制，类似于放电电容器。氧化膜的质子损失取决于它在缓冲溶液中保持的时间，这个过程随着pH值的升高而加速。薄膜制造体积的增加降低了表面电荷相对于体电荷变化的重要性，导致传感器响应的灵敏度和稳定性降低。因此，材料用量越小，器件的传感性能越好。(C)2012年电化学会。版权所有。
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.