Photoreactive π-conjugated star-shaped molecules for the organic field-effect transistor

A number of semiconducting organic molecules capable of wet processing exhibit high carrier mobility and current modulation. In this work, we synthesized photopatternable pi-conjugated star-shaped molecules and characterized their physical properties. The solubility of the synthesized molecules is very good for solution processing. The synthesized organic semiconducting multi-branched molecules are capable of photopatterning by virtue of photopolymerization of the reactive pentadienyl end groups. The transistor devices using these molecules provided a field-effect mobility of 1.3(+/-0.2) x 10(-3)-3.7(+/-0.5) x 10(-3) cm(2) V-1 s(-1) as well as a high current on/off ratio (I-on/off > 10(3)) and a low threshold voltage. In the case of the photoreactive star-shaped conjugated molecule HP2P, it was found that field-effect mobility was maintained even after the photocrosslinking process. This result can be used in the design of photo patternable semiconductor molecules for thin-film transistor electronic applications. (C) 2009 Elsevier B.V. All rights reserved.