Effect of composition on sensing properties of SnO₂ + In₂O₃ mixed nanostructured films

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• 作者：L.I. Trakhtenberg^a  ; [Author Vitae] ; G.N. Gerasimov^a  ; [Author Vitae] ; V.F. Gromov^a  ; [Author Vitae] ; T.V. Belysheva^a  ; [Author Vitae] ; O.J. Ilegbusi^b ; ^{ilegbusi@ucf.edu}  ; [Author Vitae]
• 关键词：Chemical sensor ; Gas sensor ; Conductometric sensor ; Mixed oxide nanocomposite film ; Sensor mechanism
• 刊名：Sensors and Actuators B ; Chemical
• 出版年：2012
• 期刊代码：161_09254005
• 类别：et
• 出版时间：5 July, 2012
• 卷：169
• 期：Complete
• 页码：32-38
• 文件大小：579 K

摘要

The conductometric response of SnO₂ + In₂O₃ nanocomposite films to hydrogen and carbon monoxide in air are investigated experimentally for varying oxide compositions. The fundamental mechanism of sensory phenomena in such nanocomposite films is also discussed. The experimental results indicate that the response (胃_com) of the sensor is determined by the current flow path in the film. For composites with In₂O₃ composition (X_In) less than 20 wt.%, current flows through the SnO₂ crystals. Due to electron transfer from the In₂O₃ inclusions to the SnO₂ matrix, an increase in X_In up to 20 wt.%leads to a significant increase in the conductivity of the composite sensor and 胃_com for both CO and H₂. A further increase in X_In results in percolation transition for In₂O₃ nanocrystals, which form conducting clusters (threads) of In₂O₃, with electrical conductivity that is much higher than that of SnO₂. The transition from conduction through the SnO₂ crystals to conduction through the In₂O₃ crystals in the composite films occurs at X_In in the range about 20-50 wt.%. For X_In 鈮?#xA0;50 wt.%, 胃_com is entirely determined by the sensory properties of the In₂O₃ conducting clusters, and electron transfer from In₂O₃ clusters to SnO₂ results in a decrease of 胃_com.