logo université de Strasbourg logo CNRS logo INSA Strasbourg logo ENGEES

MATISEN team: Materials for information technology, sensing and energy conversion.

Chemical sensors

De MATISEN team: Materials for information technology, sensing and energy conversion.
Révision datée du 24 août 2016 à 14:51 par Eckert (discussion | contributions) (Suppression du texte en français et remplacement de capteurCaracteristiques2RedF.jpg par capteurCaracteristiques2RedE.jpg)
Aller à la navigation Aller à la recherche


Chemical sensors

OFETs in configuration bottom contact/bottom gate can be used as chemical sensors when their channel, made of the organic material, is exposed to a gas that has to be analysed. In practice, an element to be sensed (ethanol, acetone, etc.), else called analyte, est introduced mixed to a carrier gas (here N2), on the channel of the transistor. A specially dedicated bench (Fig. 1) allows to measure at the same time the concentration of analyte in the mixture and the output characteristics of the transistor.
At first, the output characteristics of the organic transistor are measured for various concentrations of a given analyte (Fig. 2). Repeating these measurements pour different analytes allows to establish calibration tables.
Secondly, measuring the output characteristics of the organic transistor for an unknown analyte, at a concentration as well unknown, and comparing these characteristics with the calibration table informs about the type of analyte (selectivity) and about its concentration (sensitivity).

Characterisation bench of organic chemical sensors
Transfer characteristics of a transistor made from P3HT exposed to a mixture of N2 and ethanol
Fig. 1 : Characterisation bench of chemical sensors based on organic field-effect transistors. Fig. 2 : Behavior of hole mobility, hysteresis of the transfer characteristics and drain-current (for fixed drain-source Vds and gate-source Vgs voltages), for different ethanol concentrations, during exposure of a transistor with P3HT (PhD thesis of P. Lienerth).