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Journal of Nanomaterials
Volume 2012, Article ID 145406, 5 pages
Research Article

SnO2 Nanoparticle-Based Passive Capacitive Sensor for Ethylene Detection

1Integrated Nanosystems Development Institute (INDI), Indiana University-Purdue University Indianapolis (IUPUI), 723 W. Michigan Street, Indianapolis, IN 46202, USA
2Foxconn International Holdings (FIH), 1551 Sawgrass Corporate Parkway, Sunrise, FL 33323, USA

Received 24 March 2012; Accepted 1 June 2012

Academic Editor: Grégory Guisbiers

Copyright © 2012 Mangilal Agarwal 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.


A passive capacitor-based ethylene sensor using SnO2 nanoparticles is presented for the detection of ethylene gas. The nanoscale particle size (10 nm to 15 nm) and film thickness (1300 nm) of the sensing dielectric layer in the capacitor model aid in sensing ethylene at room temperature and eliminate the need for microhotplates used in existing bulk SnO2-resistive sensors. The SnO2-sensing layer is deposited using room temperature dip coating process on flexible polyimide substrates with copper as the top and bottom plates of the capacitor. The capacitive sensor fabricated with SnO2 nanoparticles as the dielectric showed a total decrease in capacitance of 5 pF when ethylene gas concentration was increased from 0 to 100 ppm. A 7 pF decrease in capacitance was achieved by introducing a 10 nm layer of platinum (Pt) and palladium (Pd) alloy deposited on the SnO2 layer. This also improved the response time by 40%, recovery time by 28%, and selectivity of the sensor to ethylene mixed in a CO2 gas environment by 66%.