Stability of Polythiophene-Based Transistors upon Bending for Gas Sensing Applications

Abstract

It is presented herein a fabrication procedure for organic thin film transistors over flexible substrates, as well as an evaluation of the electrical performance upon bending stresses. Top gate/bottom contact flexible transistors of poly(3-hexylthiophene) (P3HT) were successfully fabricated, by carefully tuning organic films drying temperatures, photolithography solvents and the pattern of electrode pads. The transistors were processed over both rigid and flexible substrates for comparison purposes. A P3HT hole mobility approaching 0.01 cm²/Vs was observed for all devices and even on different substrates. In spite of a current modulation of ca. 10, P3HT over poly(ethylene terephthalate) (PET) featured transistor behavior upon bending down to a curvature radius of 8 mm. Bending direction, however, produced different effects on the transistor characteristics, especially on gold electrodes.