Solution-Processable, Transparent Polyimide for High-Performance High-k Nanocomposite: Synthesis, Characterization, and Dielectric Applications in Transistors

Preparation and Application of Organic-Inorganic Nanocomposite Materials in Stretched Organic Thin Film Transistors

High-transparency soluble polyimide with COOH and fluorine functional groups and TiO₂-SiO₂ composite inorganic nanoparticles with high dielectric constants were synthesized in this study. The polyimide and inorganic composite nanoparticles were further applied in the preparation of organic-inorganic hybrid high dielectric materials as the gate dielectric for a stretchable transistor. The optimal ratio of organic and inorganic components in the hybrid films was investigated. In addition, Jeffamine D2000 and polyurethane were added to the gate dielectric to improve the tensile properties of the organic thin film transistor (OTFT) device. PffBT4T-2OD was used as the semiconductor layer material and indium gallium liquid alloy as the upper electrode. Electrical property analysis demonstrated that the mobility could reach 0.242 cm²·V⁻¹·s⁻¹ at an inorganic content of 30 wt.%, and the switching current ratio was 9.04 × 10³. After Jeffamine D2000 and polyurethane additives were added, the mobility and switching current could be increased to 0.817 cm²·V⁻¹·s⁻¹ and 4.27 × 10⁵ for Jeffamine D2000 and 0.562 cm²·V⁻¹·s⁻¹ and 2.04 × 10⁵ for polyurethane, respectively. Additives also improved the respective mechanical properties. The stretching test indicated that the addition of polyurethane allowed the OTFT device to be stretched to 50%, and the electrical properties could be maintained after stretching 150 cycles.