Flexible low-voltage organic thin-film transistors enabled by low-temperature, ambient solution-processable inorganic/organic hybrid gate dielectrics

We report here on the design, synthesis, processing, and dielectric properties of novel cross-linked inorganic/organic hybrid blend (CHB) dielectric films which enable low-voltage organic thin-film transistor (OTFT) operation. CHB thin films (20-43 nm thick) are readily fabricated by spin-coating a zirconium chloride precursor plus an α,ω-disilylalkane cross-linker solution in ambient conditions, followed by curing at low temperatures (∼150 °C). The very smooth CHB dielectrics exhibit excellent insulating properties (leakage current densities ∼10^-7 A/cm²), tunable capacitance (95-365 nF/cm²), and high dielectric constants (5.0-10.2). OTFTs fabricated with pentacene as the organic semiconductor function well at low voltages (<-4.0 V). The morphologies and microstructures of representative semiconductor films grown on CHB dielectrics prepared with incrementally varied compositions and processing conditions are investigated and shown to correlate closely with the OTFT response.