Experimental and modeling study of low-voltage field-effect transistors fabricated with molecularly aligned copolymer floating films

In order to reduce the cost of next generation flexible and printed electronic devices, and enhance their performance, it is expected that they can be produced using simple solution processable techniques. In this paper, we have successfully demonstrated the application of a simple method to obtain molecularly aligned floating films of an organic semiconducting polymer, diketopyrrolopyrrole-naphthalene (PDPP-TNT), on top of water. The macromolecular alignment in these films deposited over glass susbstrates was confirmed by atomic force microscopy, polarized optical microscopy and polarized UV–vis absorbance spectroscopy. When the PDPP-TNT floating films were deposited as the active layer in organic field-effect transistors (OFETs), the devices exhibited mobility values as high as 1.3 cm2 V−1 s−1 at low operating voltages (6 V). Furthermore, we have also performed a theoretical modeling study using Aim-Spice Level 15 model to extract the OFET parameters. By varying the tuning parameters, the modeling data fits well with the experimental data of PDPP-TNT OFETs.