Micropatterning of thin P3HT films via plasma enhanced polymer transfer printing

We have developed a simple but robust process, plasma enhanced polymer Transfer printing (PEPTP), for fabricating micropatterns of semi-conducting poly(3-hexyl thiophene) (P3HT) thin films. The method is based on transferring thin P3HT film spin cast directly on a pre-patterned elastomeric poly(dimethyl siloxane) (PDMS) mold. Printing is accomplished by the application of oxygen plasma on both P3HT film and substrate for surface energy modulation at ambient conditions without additional pressure. The control of the relative interfacial surface energy by the plasma enables us to micro/nanopattern a wide range of polymers from P3HT to conventional insulating ones on various substrates including Si, glass and polymers over large areas. A bottom contact organic thin film transistor with the printed P3HT patterns using PEPTP exhibits a carrier mobility of approximately 0.02 cm² V^-1 s^-1 with a relatively high on/off current ratio of 6 × 10³.