We demonstrate the gravure printing of a high-performance indacenodithiophene (IDT) copolymer, indacenodithiophene–benzothiadiazole (C16IDT–BT), onto self-aligned organic field-effect transistor architectures on flexible plastic substrates. We observed that the combination of a gravure-printed dielectric with gravure-printed semiconductor yielded devices with higher mean-effective mobility than devices manufactured using photolithographically patterned dielectric. Peak mobilities of μ = 0.1 cm2 V−1 s−1 were measured, and exceed previous reports for non-printed C16IDT-BT on non-flexible silicon substrates.

This article discusses the importance of the choice of synthetic methodology in the purity, and therefore performance, of both small-molecule and polymeric organic semiconductors. We discuss common methodologies used in the preparation of organic semiconductors, paying particular attention to the impurities and by-products that can arise during these synthetic approaches and how they can have an impact on semiconductor performance.

Until recently, the synthesis of polythiophenes using Suzuki chemistry has proven difficult because of the ready protodeborylation of thiophene boronates. However, we now report that the new generation of bulky, electron-rich Pd(0)-phosphane catalysts are effective and reliable for the preparation of regioregular polyalkylthiophenes using Suzuki coupling. Moreover, the monomers can be prepared in high yield by Ir-catalysed borylation, without the need for strong organolithium bases, making this potentially a highly functional group-tolerant approach to polyalkylthiophene derivatives. Perfluoroalkylthiophenes also undergo this reaction.

Organic thin film transistor (OTFT) gas sensors fabricated with an array of different active materials are monitored for shifts in performance characteristics during continuous operation over many days in both inert and ambient environments. We analyze the different patterns of degradation behavior observed in different materials and discuss approaches to decoupling a device's sensor response from its stress response.

The performance of the semiconducting component in organic field effect transistors (OFET's), is a key parameter in the advancement of organic electronic devices. This work describes the development of solution processible liquid crystalline semiconductors, both main chain rigid rod polymers and small molecule polymerisable liquid crystals, referred to as reactive mesogens. New conjugated main chain polymeric semiconductors have been designed, synthesised, and their performance in transistor devices is reported. Small molecule liquid crystalline semiconductors, which contain reactive end groups, were also prepared, and their design, characterisation, and performance in transistor devices is discussed.