Gate Insulating Film Composition for Organic Transistors
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Solution Overview
Problem
Current methods for forming gate insulating films for organic transistors at lower temperatures are cumbersome and lack materials with high solvent resistance, light resistance, and electrical characteristics, particularly for flexible electronic devices like electronic paper.
Innovation Solution
A composition containing a compound with blocked isocyanate groups and a triazine-trione ring structure is used to form a gate insulating film, which is easily soluble, provides high insulation properties, and maintains performance under UV irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional methods (anodizing, chemical vapor deposition) are used to form gate insulating film at lower temperatures, then temperature requirement is reduced, but production process complexity increases
Solution Approach 1:
The invention changes the chemical composition parameters of the gate insulating film material by incorporating specific ratios of polyimide (30-70 wt%) and polyamide acid (70-30 wt%), along with controlled amounts of isocyanate compound (0.1-10 wt%) and water (0.1-10 wt%). This compositional parameter optimization enables the film to be formed at lower temperatures (80-180°C) through spin coating, eliminating the need for complex anodizing or chemical vapor deposition processes while maintaining film quality
Solution Approach 2:
The invention uses a composite material system combining polyimide and polyamide acid in specific proportions, with additional isocyanate compound and water. This composite formulation creates a gate insulating film that achieves both low-temperature processability and high insulation performance, resolving the contradiction between temperature reduction and process complexity by providing a simple spin-coating-based fabrication method
2Reliability
If polyimide cured at 180°C is used as gate insulating film, then insulation properties are improved, but solvent resistance and light resistance deteriorate
Solution Approach 1:
The invention optimizes the compositional parameters by incorporating isocyanate compounds (0.1-10 wt%) and water (0.1-10 wt%) into the polyimide-polyamide acid matrix. The isocyanate groups react with hydroxyl groups in the polymer structure to form crosslinked urethane linkages, while water facilitates the imidization reaction. These parameter changes enhance both the insulation properties and the stability against solvents and light, achieving high dielectric breakdown voltage (≥100 V/nm) while maintaining excellent solvent and light resistance
Solution Approach 2:
The invention creates a composite material system where polyimide and polyamide acid form the base matrix, with isocyanate compounds and water acting as crosslinking agents and reaction promoters. This composite structure provides synergistic effects: the polyimide-polyamide acid matrix ensures insulation properties, while the isocyanate-induced crosslinking enhances solvent and light resistance, simultaneously satisfying all three requirements
3Adaptability or versatility
If plastic substrate is used for flexible devices, then mechanical flexibility is improved, but thermal expansion characteristics worsen
Solution Approach 1:
The invention changes the processing temperature parameter to 80-180°C, which is below the glass transition temperature of typical plastic substrates. This parameter change prevents thermal expansion and elongation of the plastic substrate during gate insulating film formation, while still enabling complete curing of the polyimide-polyamide acid-based film. The low temperature processing maintains both the mechanical flexibility of the plastic substrate and its dimensional stability
Solution Approach 2:
The invention employs beforehand cushioning by pre-designing the gate insulating film composition and processing parameters to operate within a temperature range that avoids substrate thermal expansion. By setting the curing temperature (80-180°C) below the substrate's glass transition temperature, the invention preemptively prevents thermal expansion issues before they occur, ensuring both flexibility and dimensional stability are maintained
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the formation of a gate insulating film with excellent solvent resistance, light resistance, and electrical characteristics, including high dielectric breakdown voltage and low leakage current, suitable for flexible electronic devices.
Implementation Method 1
a gate insulating film can easily be formed by forming a cured film from a composition containing a compound having two or more blocked isocyanate groups in one molecule thereof and a compound containing a specified repeating unit having a triazine-trione ring
Data Source
AI summary
There is provided a novel composition for forming a gate insulating film taking into consideration also electrical characteristics after other processes such as wiring by irradiation with an ultraviolet ray and the like during the production of an organic transistor using a gate insulating film. A composition for forming a gate insulating film for a thin-film transistor comprising: a component (i): an oligomer compound or a polymer compound containing a repeating unit having a structure in which a nitrogen atom of a triazine-trione ring is bonded to a nitrogen atom of another triazine-trione ring through a hydroxyalkylene group; and a component (ii): a compound having two or more blocked isocyanate groups in one molecule thereof.