Vol. 125, Issue 2, February 2011, pp.89-99

Characterization of WO₃-SnO₂ Nanocomposites and Application in Humidity Sensing

¹N. K. Pandey, ²Akash Roy, ³Alok Kumar

^{1, 2}Sensors and Materials Research Laboratory, Department of Physics,

University of Lucknow, Lucknow-226007, India

³Mineral Physics Division, Geological Survey of India, Northern Region, Lucknow, India

Tel.: 91-9919501803

²E-mail: akashroy77@rediffmail.com

Received: 1 February 2011   /Accepted: 15 February 2011   /Published: 28 February 2011

Abstract: Pellet samples of WO₃-SnO₂ nanocomposite in the weight % ratio of 85:15 have been prepared and annealed at temperatures 300-600 °C for 3 hours. When exposed to humidity, the sample shows maximum sensitivity of 23.41 MΩ/%RH for the annealing temperature 600 °C. For this annealing temperature of 600 °C, the sample shows low ageing effect after four months. The hysteresis (between humidification and desiccation, measured in the RH range of 15–90 % RH) for the annealing temperature of 600 °C is less than 8 % RH. Activation energy measured from Arrhenius plot in 50 to 300 °C and 300 to 600 °C range have been found to be 0.12 and 0.54 eV respectively. The response time and recovery time for the sample annealed at 600 °C are 121 seconds and 912 seconds respectively. The grain size and crystallite size of the pellets are found to be in the nanometer range. An observation of the crystallite size and grain size would suggest that smaller crystallites are getting agglomerated to form larger grains.

Keywords: WO₃, SnO₂, Nanocomposites, Humidity sensing, XRD

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