Conducting Langmuir-Blodgett films of tetracyanoquinodimethane and ethylenedithio-tetrathiafulvalene derivatives applied to gas sensing: gas diffusion and detection ranges

Conducting Langmuir-Blodgett (LB) films based on tetracyanoquinodimethane (TCNQ) and ethylenedithio-tetrathiafulvalene (EDT-TTF) appear to be very promising candidates for phosphine sensors. Gas diffusion through the LB structure is an important factor which must be controlled. The study of a molecular assembly of silver behenate underlayers (the reaction of which towards PH3 is followed by infrared spectroscopy) on top of which the conducting film is transferred shows that phosphine penetration in these conducting films limits the response time of the sensor. The two types of conducting films lead to two different sensors.