Organic Thin Film Transistor with Polysiloxane Coating
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Solution Overview
Problem
Existing organic thin film transistors face challenges in achieving high charge mobility and reliability due to the need for expensive vacuum deposition processes and difficulties in forming homogeneous organic semiconductor layers using solution processes, particularly with low surface energy substrates.
Innovation Solution
A thin film transistor is developed with an inorganic insulating layer coated with a polysiloxane having an acrylic terminal group, allowing for a solution-processable organic semiconductor layer with improved crystallinity and wetting properties, enhancing charge mobility and device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum deposition process is used to form organic semiconductor layer, then manufacturing precision and reliability are improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical vacuum deposition process with a solution-based coating process. The organic semiconductor is dissolved in a solvent to form a solution, which is then coated onto the substrate using simple techniques such as spin coating, dip coating, or inkjet printing. This substitution eliminates the need for complex vacuum equipment while achieving homogeneous layer formation through the self-assembly properties of the solution-cast organic semiconductor molecules.
Solution Approach 2:
The patent changes the physical state of the organic semiconductor from solid (requiring vacuum deposition) to dissolved state (enabling solution processing). By selecting appropriate solvents and controlling solution concentration, the organic semiconductor forms a homogeneous layer upon solvent evaporation. The patent also optimizes parameters such as coating speed, temperature, and solvent composition to achieve desired layer quality without vacuum equipment.
2Ease of manufacture
If solution process is used to apply organic semiconductor, then ease of manufacture is improved, but manufacturing precision deteriorates due to difficulty in forming homogeneous layers
Solution Approach 1:
The patent introduces a self-assembled monolayer (SAM) as an intermediary between the inorganic insulating layer and the organic semiconductor solution. This SAM layer, formed by treating the insulator surface with silane or fluorosilane compounds, acts as a mediator that promotes uniform nucleation and growth of the organic semiconductor. The SAM provides controlled surface energy and molecular orientation, enabling homogeneous layer formation from solution without requiring complex process control.
Solution Approach 2:
The patent performs preliminary surface treatment of the inorganic insulating layer before applying the organic semiconductor solution. The insulator surface is pre-coated with a self-assembled monolayer through chemical treatment with silane-based compounds. This preliminary action creates a controlled surface environment that guides the subsequent organic semiconductor deposition, ensuring homogeneous layer formation even with simple solution coating techniques.
3Ease of manufacture
If low surface energy substrate is used, then ease of manufacture is improved, but reliability deteriorates due to poor wetting properties of organic semiconductor solution
Solution Approach 1:
The patent changes the surface energy parameters of the substrate by introducing a self-assembled monolayer with controlled chemical composition. The SAM layer, formed from silane or fluorosilane compounds, provides optimized surface energy that enhances wetting of the organic semiconductor solution. This parameter change transforms the low surface energy characteristic of bare inorganic insulators into an optimal surface energy state that promotes both adhesion and homogeneous coverage.
Solution Approach 2:
The patent creates a composite surface structure consisting of an inorganic insulating layer combined with an organic self-assembled monolayer. This composite material approach allows the substrate to maintain its mechanical and electrical properties while the SAM layer provides enhanced surface properties for solution wetting. The composite structure combines the advantages of inorganic insulators with the surface-active properties of organic monolayers.
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-processable organic semiconductor layer demonstrates high charge mobility and improved reliability, simplifying the manufacturing process while maintaining high performance, as evidenced by charge mobility values exceeding previous comparative examples.
Implementation Method 1
the surface includes a coating with a polysiloxane having an acrylic terminal group
Implementation Method 2
allowing for a solution-processable organic semiconductor layer with improved crystallinity
Data Source
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AI summary
A thin film transistor includes a gate electrode, a semiconductor overlapping the gate electrode, an insulator between the gate electrode and the semiconductor, and a source electrode and a drain electrode electrically connected to the semiconductor, where the semiconductor being an organic semiconductor capable of being applied by a solution process, and where the insulator including an inorganic insulating layer, and a surface of the inorganic insulating layer facing the organic semiconductor being coated with a polysiloxane having an acrylic terminal group.