Modified poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) source/drain electrodes for fully printed organic field-effect transistors consisting of a semiconductor blend

The influence of post-press treatment on the modification of printed source/drain electrodes made of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with ethylene glycol is presented. Beside changes of the geometry and the conductivity of these mass printed structures, the work function of PEDOT:PSS can be tuned, leading to an improved performance of organic field effect transistors (OFETs). OFETs were built up with a new small molecule/polymer blend consisting of 6,13-bis[(cyclopropyldiisopropylsilyl)ethynyl] pentacene and poly(triarylamine), providing a field effect mobility of 0.2 cm2/Vs for fully printed devices in air. Ring oscillators based on these OFETs demonstrate a frequency of more than 1 kHz.