Natural polymers for disposable organic thin film transistors

Abstract

In this study, eco-friendly PTCDI-C8-based organic thin film transistors (OTFTs) were fabricated by incorporating polymers from renewable sources as gate dielectrics and substrates. Chitosan, a polysaccharide obtained from the deacetylation of chitin, and natural rubber (NR), extracted from natural rubber tree, have good dielectric properties, biocompatibility, and biodegradability. To examine the practical applicability of these materials, we fabricated OTFTs using bilayer PVPy/NR and chitosan/NR films as gate dielectric materials. NR not only improved the insulation properties of the dielectric film but also acted as a surface modifier. The fabricated OTFT incorporating chitosan/NR dielectric operated under a low driving voltage, with values of mu and V-th of 0.027 cm(2)V(-1)s(-1) and 0.83 V, respectively. It also displayed an electrical response in the presence of DNA at different concentrations. Because, chitosan possesses high transparency and good mechanical properties, it can be readily cast to form transparent flexible substrates. Accordingly, a flexible disposable OTFT device was fabricated using PVPy/NR as the dielectric material on chitosan as the substrate. The disposable device exhibited a carrier mobility of 0.011 cm(2)V(-1)s(-1), a value of V-th of 0.83 V, and an on/off ratio of 10(3), while being workable over 100 bending cycles.