A blend of organic semiconductors and photocrosslinkable insulating polymers was photolithographically patterned to yield organic thin-film transistors (OTFTs). The semiconducting polymer of the blend, poly(3-hexylthiophene), was present as a nanofibrillar network and yielded excellent electronic properties. The insulating polymer matrix, poly(vinyl cinnamate), provided the photosensitivity required for photopatterning. The photopatterned TFT devices showed large on/off ratios (>10 5 ) and high mobilities (0.015 cm 2 V À1 s À1 ) comparable to those of devices patterned by conventional means using the same semiconducting materials. This simple method permitted the highresolution cost-effective patterning of organic semiconductors and may play an important role in the mass-production of organic electronic devices.

A melt processed polymer blend based on poly(3-hexylthiophene) (P3HT) and an insulating polymer with good melt-processability, poly(3-caprolactone) (PCL), has been demonstrated for fabricating organic thin-film transistors. The P3HT component in the blend, presenting as nanofibrillar networks, provides the blend with an excellent charge-transport property at low P3HT content, and the PCL matrix with a low melt temperature allows the blend to be processed at a temperature as low as 60 C. The field-effect characteristics of the melt-processed transistors are comparable to those of the solutionprocessed device. The blend displays outstanding mechanical properties with elongations at break exceeding 300%, and has a potential use in biocompatible and biodegradable organic thin-film transistors.

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