《Vacuum-deposited nanocrystalline polyaniline thin film sensors for detection of carbon monoxide》.pdfVIP

Sensors and Actuators A 114 (2004) 30–35 Vacuum-deposited nanocrystalline polyaniline thin film sensors for detection of carbon monoxide S.C.K. Misra a,∗, Prafull Mathur a , B.K. Srivastavab a National Physical Laboratory, New Delhi 110012, India b Narain (PG) College, Shikohabad, India Received 16 August 2003; received in revised form 26 January 2004; accepted 13 February 2004 Available online 1 April 2004 Abstract Gas sensors based on metal oxide semiconductors are widely used for detection of toxic gases like CO. These sensors suffer from the draw back of limited lifetime due to their operation at high temperatures. On the other hand it is often difficult to achieve high sensitivity, selectivity, and specificity in presence of a mixture of gases. To overcome this, vacuum-deposited nanocrystalline polyaniline thin films have been found suitable for detection of carbon monoxide. The sensors using these films operate at room temperature. A high sensitivity, selectivity, specificity, and a fast response time have been achieved. High sensitivity, selectivity, and specificity are obtained by doping the polyaniline powder during synthesis. These thin film sensors are highly stable, reliable, and their gas detection limit is low. © 2004 Elsevier B.V. All rights reserved. Keywords: Gas Sensor; Semiconductors; Carbon monoxide 1. Introduction operate at room temperature. Recently there has been a re- markable growth in the development of electroactive semi- Carbon monoxide,