Role of geometry, substrate and atmosphere on performance of OFETs based on TTF derivatives

We report a comparative study of OFET devices based on zone-cast layers of three tetrathiafulvalene (TTF) derivatives in three configurations of electrodes in order to determine the best performing geometry. The first testing experiments were performed using SiO2/Si substrates. Then the optimum geometry was employed for the preparation of flexible OFETs using Parylene C as both substrate and dielectric layer yielding, in the best case, to devices with mu(FET) = 0.1 cm(2)/V s. With the performed bending tests we determined the limit of curvature radius for which the performance of the OFETs is not deteriorated irreversibly. The investigated OFETs are sensitive to ambient atmosphere, showing reversible increase of the source to drain current upon exposition to air, what can be explained as doping of TTF derivative by oxygen or moisture. (C) 2011 Elsevier B. V. All rights reserved.