Materials Science-Poland, Vol. 28, No. 2, 2010 Humidity sensing properties of TiO 2 –Sb 2 O 5 nanocomposite A. K. SRIVASTAVA, B. C. YADAV * Nanomaterials and Sensors Research Laboratory, Department of Physics, University of Lucknow, Lucknow-226007, India The syntheses of TiO 2 –Sb 2 O 5 (AT) composites were investigated by the conventional precipitation method and their use as humidity sensors. 2–50 wt. % of Sb 2 O 5 was added to TiO 2 and pellets were made under the pressure of 616 MPa a room temperature of 30ºC. The pellets were annealed at various tem- peratures (200, 500, 700 and 800 °C) for 3 h and the humidity sensing properties of each pellet were studied. A saturated aqueous solution of potassium sulphate was used as the humidifier and a saturated solution of potassium hydroxide was used as the dehumidifier. Upon increasing relative humidity (RH) inside the test chamber, the resistance of each pellet decreased for the RH range from 10% to 95%. Sam- ples of the sensor material, differing in the percentage of the additive, were subject to SEM and XRD analysis. The minimum grain size, estimated from SEM, was 30 nm and the minimum crystallite size from XRD data was 20 nm. The material was found to have suitable properties to be applied as a resistive humidity sensor operating over the entire humidity range. Keywords: titania; humidity; nanocomposite; resistance; sensor; adsorption 1. Introduction TiO 2 is an important technological material used in electronic [1], electrical [2, 3], op- tical [4–6] and catalytic devices [7, 8] due to of its high electric permittivity, large birefringence, chemical stability and high photocatalytic activity. Physical properties of TiO 2 have been the subject of various investigations in terms of its suitability for various applications. TiO 2 occurs in three crystalline polymorphs: rutile, anatase and brookite, rutile being the most stable phase. Doping with impurities such as In, Cr, Cd, Fe and Co can change the magnetic and semiconducting properties of TiO 2 . Among various oxide semiconductors, titania appears promising and important for the use in environmental purification, due to its strong oxidizing power, non-toxicity and long _________ * Corresponding author; e-mail: balchandra_yadav@rediffmail.com