High Electron Mobility and Ambient Stability in Solution-Processed Perylene-Based Organic Field-Effect Transistors

The realization of bottom-contact bottom-gate organic field-effect transistors (OFETs) based on spin-coated films of N,N'-1H, 1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDIF-CN₂), was reported. These substrates were treated with both hexamethildisilazane (HMDS) and 3,5-bis(trifluoromethyl)thiophenol before semiconductor-layer deposition. The semiconductor film was spin-coated on the insulator/contact surface using a chloroform solution of PDIF-CN₂. The devices were then annealed at 110°C in a vacuum oven for 60 min, and finally tested. In order to rationalize the electrical characteristic variations upon annealing, the semiconductor-film morphologies were investigated by atomic force microscopy (AFM) and confocal laser microscopy (CLM). The difference in the optical microscopy images of the PDIF-CN₂ film and in the photoluminescence images obtained by CLM provides demonstration of the enhanced order of the annealed films. Good air stability is also observed, since the devices show stable mobility value after 20 days of continuous exposure to air.