WO3 Nanograined chemosensor: a model of the sensing behavior

In this work the influence of the grain dimension on WO3 chemosensor response is studied. For this material the dielectric constant can assume very large values especially when increasing the operating temperature. As a consequence the Debye length can increase so that the sensor changes from a 'large grain' behavior to a 'small grain' one. This is true indeed for nano-grained powder. The sensitivity of nano-grains is higher but a complete depletion can occur saturating therefore the sensors. The case of spherical grains will be discussed in order to point out that, given the grain size, the variations of the material characteristics change the behavior. Different approximations are compared and discussed