Stability and 2,4-dinitrotoluene response of organic field effect transistors based on π-conjugated thiophene oligomers

This paper reports on organic field effect transistors (OFETs) based on two π-conjugated oligomers derived from thiophenes and their use as sensors for the detection of 2,4-dinitrotoluene (DNT). The detection mechanism relies on donor-acceptor interactions between the π-conjugated system (donor) and the nitrated molecule (acceptor). An important feature of sensors is the stability under operation, so, a large part of this work will be dealing with the behavior of OFETs under bias stress experiments as well as with the influence of temperature during operation. Most of results reported here are concerning hexyl capped tetra Thienylene–Vinylene (denominated 4-TV). Some preliminary results on the promising hexyl capped quinquethiophene derived from 3,4-ethylenedioxythiophene (denominated TETET) are also reported. Under a DNT contaminated air atmosphere (∼ 7 ppm), 4-TV based OFETs exhibit an increase of the drain current when DNT is present in the atmosphere as expected.