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Journal of Sensors
Volume 2011 (2011), Article ID 824215, 8 pages
http://dx.doi.org/10.1155/2011/824215
Research Article

Nano Ag-Doped Thick Film: A Low-Temperature Gas Sensor

1Department of Chemistry, Arts Commerce and Science College, Lasalgaon 422 306, India
2Materials Research Lab., Arts, Commerce and Science College, Nandgaon 423 106, India
3Materials Research Lab., K.T.H.M. College, Nashik 422 005, India
4Applied Chemistry and Nanoscience DIAT, Govt. of India, Girinagar Pune 411 025, India

Received 17 May 2011; Accepted 18 July 2011

Academic Editor: P. Siciliano

Copyright © 2011 D. N. Chavan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Thick films of AR grade In2O3 were prepared by standard screen-printing technique. The gas sensing performances of thick films were tested for various gases. It showed maximum sensitivity to ethanol vapour at 350°C for 80 ppm concentration. To improve the sensitivity and selectivity of the film towards a particular gas, In2O3 sensors were surface-modified by dipping them in a solution of 2% nanosilver for different intervals of time. Obtained results indicated that spherical nano-Ag grains are highly dispersed on the surface of In2O3sensor. The surface area of the nano-Ag/ In2O3 sensor is several times larger than that of pure In2O3 sensor. In comparison with pure In2O3 sensor, all of the nano-Ag-doped sensors showed better sensing performance in respect of response, selectivity, and optimum operating temperature. The surface-modified (30 min) In2O3 sensor showed larger sensitivity to H2S gas (10 ppm) at 100°C. Nano silver on the surface of the film shifts the reactivity of film from ethanol vapour to H2S gas. A systematic study of gas sensing performance of the sensor indicates the key role played by the nano silver species on the surface. The sensitivity, selectivity, response, and recovery time of the sensor were measured and presented.