Facile Development of Conjugated Polymer Network in Semiconducting Blend Films for Flexible Organic Field-Effect Transistors

초록

Mechanically durable polymer semiconductor/soft elastomer blends are promising composites for flexible organic field-effect transistor (OFET) applications. Here, nanofibrillar network structures of poly(3-hexyl thiophene) (P3HT) embedded in a cured polydimethylsiloxane (PDMS) elastomer matrix were facilely developed via blending of ultrasound-assisted P3HT mother solutions and PDMS pre-polymer, spin-casting, and curing. Blend film morphologies of P3HT/PDMS (1/9 in w/w) on polymer-coupled SiO2 dielectrics could be controlled reproducibly by elongating the ultrasonic time, which significantly improved the aggregates of P3HT self-assembled directly in the solutions, while simple solution blending of these two immiscible materials yielded the micro-phase separated domains in the cast blend films. The optimization of ultrasound-assisted solution processing could produce optically feature-less blend films. P3HT/PDMS blend OFETs prepared from 10 - 15 min ultrasound-assisted P3HT solutions showed high electrical performance: field-effect mobility of about 0.03 cm2V-1s-1 and on/off current ratio of > 5×105, as well as uniform and smooth cast films, P3HT nanofibrils embedded were well-dispersed and percolated in the elastomer negligible hysteresis and environmental stability by the PDMS-surrounding channel.