A water-soluble polythiophene for organic field-effect transistors

Synthesis of a non-ionic, water-soluble poly(thiophene) (PT) derivative, poly(3-(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)methylthiophene) (P3TEGT) with a hydrophilic tri-ethylene glycol side group, is reported and thin films of the polymer suitable for organic field-effect transistors (OFETs) are characterized by combining analysis techniques that include UV-Vis absorption and fluorescence spectroscopy, X-ray diffraction, and atomic force microscopy. After thermal annealing, P3TEGT films exhibit a well-organized nanofibrillar lamellar nanostructure that originates from the strong π-π stacking of the thiophene backbones. P-type organic field-effect transistors (OFETs) with hole mobilities of 10^-5 cm² V^-1 s^-1 were fabricated from this water-soluble poly(thiophene) derivative, demonstrating the possibility that environmentally friendly solvents may be promising alternatives for the low-cost, green solvent processed organic electronic device manufacturing of OFETs, organic photovoltaics (OPVs), and biosensors.