Enhanced mobility of rubrene thin-film transistors with a polymer dielectric on plastic substrate

We report on the fabrication of rubrene thin-film transistors (TFTs) with spin-coated poly-4-vinylphenol (PVP) dielectric on indium-tin oxide/plastic substrate. Under a specific growth condition of 80°C in situ vacuum anneal following thermal deposition, initial amorphous rubrene film was successfully transformed into crystalline phase, both on hydrophobic PVP and on Si O2 p+ -Si substrate, whose surface is relatively hydrophilic. The transformation or growth kinetics of the crystalline rubrene domain was much faster on PVP than on the Si O2 gate dielectric. As a result, the rubrene TFT with PVP dielectric exhibited an order of magnitude higher field mobility (∼6× 10-3 cm2 V s) than that of the other one with Si O2 dielectric.