Solution-processable organic-capped titanium oxide nanoparticle dielectrics for organic thin-film transistors

Oleic acid-capped titanium dioxide (OA-TiO2) nanoparticles were solution-processed to form homogeneous dielectrics for organic thin-film transistors (TFTs) of top-gate and bottom-gate configurations. The OA-TiO2 nanoparticles were well-dispersed into the organic solvent and spin-coated to give homogeneous films. These nanoparticle films showed a dielectric constant of about 5.3 and low leakage current density of similar to 3x10(-8)A/cm(2) under an electric field of 1 MV/cm. Poly(3,3 '''-didodecylquaterthiophene) and pentacene TFTs with OA-TiO2 dielectrics exhibited mobilities of 0.05 +/- 0.02 and 0.2 +/- 0.05 cm(2) V(-1)s(-1), respectively, with on/off ratios of 10(3)-10(5). This material appears to be useful for applications in printable organic TFTs. (c) 2008 American Institute of Physics.