Investigation of adsorption-desorption phenomenon by using current fluctuations of amperometric NO2 gas sensor

Nitrogen dioxide (NO₂) is a highly toxic gas harmful to the environment even at low concentrations. To overcome limitations of standard solid NO₂ sensors based on inorganic materials, a fully printed sensor with solid polymer electrolytes (SPE) was developed in Regional Innovation Centre for Electrical engineering in Czech Republic. The amperometric sensor is based on a semi-planar three-electrode topology (reference, working and counter electrode) and solid polymer electrolyte. This paper focuses on adsorption-desorption phenomenon by studying current fluctuations and current mean value of amperometric NO₂ gas sensor during its exposition to concentration cycle. Limits of NO₂ concentration are from 0 to 6 ppm. Background noise and thermal noise are only apparent for zero concentration, while, noise 1/f becomes main component of current fluctuations for higher NO₂ concentrations.