PRECURSOR SYNTHESIS, COUPLING, AND TFT EVALUATION OF END-SUBSTITUTED THIOPHENE HEXAMERS

Methods for synthesizing pure, monosubstituted alpha-terthiophenes, an d selectively coupling their lithiated derivatives to produce disubsti tuted sexithiophenes were developed. The terthiophenes were made via c arbonyl intermediates that could be readily chromatographed. The coupl ing reagents were selected to minimize chlorination and lithium-hydrog en exchange. The mobility of the dihexylated hexamer in thin-film tran sitors was 0.03 cm(2)/Vs, in agreement with the literature. The on/off ratio was much higher than the literature, due to improved purity. Us e of hexylthio as a substituent gave highly conductive, poorly perform ing transistors.