Green solvent-processed complementary-like inverters based on ambipolar organic thin-film transistors

In the trends of ever-growing worldwide interest for the environment/health and the corresponding legal regulations, there have been various studies to replace toxic halogenated/aromatic hydrocarbon organic solvents commonly used in the solution-processing of organic semiconductors (OSCs) with more sustainable green solvents. In this paper, we fabricated ambipolar organic thin-film transistors (OTFTs) and complementary-like inverters by blending a p-type OSC (6,13-bis(triisopropylsilylethynyl)pentacene; TIPS-pentacene) and a n-type OSC (N,N'-di-n-octyl-3,4,9,10-perylenetetracarboxylic diimide; PTCDI-C8) in a single green solvent anisole. In particular, shellac was employed as green dielectric materials and the electrical performance of the resulting devices were compared with those fabricated using toxic solvents or commonly used oxide-based dielectrics. The bulk-heterojunction (BHJ)-structured OTFTs in the optimized condition exhibited typical ambipolar characteristics with relatively balanced charge carrier mobilities as high as 0.042 and 0.14 cm2 V−1s−1 for hole and electron, respectively. Additionally, complementary-like inverters based on the two optimized ambipolar OTFTs showed a decent transfer gain as high as 21 at negative supply voltages of −60 V. Thus, by demonstrating the applicability of green solvents not only for OTFTs but also in the implementation of circuit devices, we expect that the results obtained will spark more interest for the more sustainable fabrication of OSC-based electronic devices and their commercialization/mass-production in the relevant industrial real cases.