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A direct photopatternable organosiloxane-based organic-inorganic hybrid gate dielectric was synthesized. The sol-gel derived hybrid dielectric could be cured at a temperature sufficiently low enough to apply to temperature-sensitive polymeric substrates, whilst maintaining good electrical properties. The addition of hexa(methoxymethyl)melamine minimizes the polar silanol group by enhancing the cross-linking reaction and improves the film density, so that the resulting hybrid dielectric retains both thermal and chemical stability against the highly basic aqueous semiconductor precursor, forming a coherent interface between the dielectric and the semiconductor. The synthesized hybrid materials allow for a high-performance solution-processed flexible ZnO transistor on polymeric substrate at 150 C.

We describe low-temperature, solution-deposited, oxide semiconductor thin-film transistors (TFTs) with a solution-processed gate dielectric in this study. The sol–gel-derived indium zinc oxide (IZO) semiconductor matched well with the organic–inorganic hybrid dielectric annealed at 200 °C, forming a coherent interface between the semiconductor and the dielectric without evidence of chemical damage. The IZO-TFTs made with a 420-nm-thick hybrid dielectric layer showed good performance: a low off-current on the order of <10-10 A, a field-effect mobility of 3.3×10-2 cm2 V-1 s-1, and a low threshold gate voltage of ∼2.4 V. Spin-coating of the IZO semiconductor on a hybrid dielectric/glass substrate results in TFTs optically transparent in the entire visible region (∼90%). Our solution-processable materials of the semiconductor and the gate dielectric can open the possibility of realizing flexible transparent devices using all-solution processing.