Oligothiophene based organic semiconductors with cross-linkable benzophenone moieties

Two oligothiophene based organic semiconductors with photo-cross-linkable benzophenone (BP) groups were synthesized and characterized. Solution cast and evaporated thin film transistors (TFTs) were created and field effect mobilities exceeding 10−3 cm2 V−1 s−1 were achieved. Upon film cross-linking the mobility increased nearly a factor of two suggesting some molecular reorganization. The stability and crosslinking of the semiconducting films were monitored by Fourier Transform Infrared Spectroscopy (FTIR). Preliminary work was also performed to study the potential of attaching analyte molecules to the semiconductor surface via photo-attachment to the BP groups for future sensor applications. The water contact angle of the semiconductor layer before and after the attachment of l-glutamic acid was measured. A drop of nearly 20 degrees suggests incorporation of the amino acid onto the surface of the semiconductor film after UV crosslinking.