All organic humidity sensors based on conjugated polymers and a tetracyanoquinodimethane salt

This work is about the development and the optical and electrical characterization of all organic heterojunctions consisting of solution deposited films of poly(3,4ethylendioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS), a few micrometers thick, coated with an ion conducting material. This latter one is a complex obtained by the charge transfer reaction that takes place when acetonitrile solutions of the electron acceptor Tetracyanoquinodimethane (TCNQ) molecules are added to solutions containing the ion conducting sodium-polystyrenesulfonate (NaPSS). The principle of operation on which such devices are based on, relies on the possibility to change optical and charge conducting properties of conjugated polymers by electrically driven oxidization and reduction transitions.