Fused Ring Compounds for Organic Thin-Film Transistors
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Solution Overview
Problem
Conventional organic thin film transistors using silicon-based semiconductors are costly and limit substrate material options due to high processing temperatures, while existing organic TFTs suffer from low mobility and high driving voltage requirements, which restrict their performance and application.
Innovation Solution
A compound with an enlarged 7-conjunction system, featuring a fused aromatic ring structure, is developed for the organic thin film transistor, enhancing mobility and reducing driving voltage, and is applicable to coating methods, allowing for a more cost-effective and versatile organic TFT production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional organic semiconductor materials (pentacene, picene) are used, then the transistor shows moderate mobility, but the driving voltage becomes excessively high (e.g., -67V for picene) or the stability deteriorates (pentacene oxidation)
Solution Approach 1:
The patent modifies the molecular structure parameters of organic semiconductors by introducing fused ring systems (anthracene, phenanthrene, chrysene cores) with specific substituents (alkyl groups, alkoxy groups, halo groups) to optimize the balance between mobility, driving voltage, and stability. This structural parameter optimization enables achieving low driving voltage (<10V) while maintaining device stability
Solution Approach 2:
The patent employs composite molecular structures combining rigid fused aromatic ring systems with flexible substituent groups. The core fused ring structure provides high mobility and stability, while the substituent groups (such as alkyl and alkoxy chains) modulate the electronic properties to reduce driving voltage, creating an optimized composite semiconductor material
2Reliability
If silicon-based semiconductors are used for TFT fabrication, then high mobility is achieved, but production cost increases significantly and substrate material selection is limited due to high processing temperatures
Solution Approach 1:
The patent replaces expensive silicon-based semiconductors with organic semiconductor compounds that can be processed at low costs using solution-based methods. These organic materials, while having shorter operational lifetimes than silicon, provide sufficient performance for display applications and enable the use of inexpensive flexible substrates, effectively trading extreme durability for manufacturability and flexibility
Solution Approach 2:
The patent substitutes the mechanical/thermal processing required for silicon semiconductor fabrication with solution-based deposition methods. Instead of high-temperature CVD processes needed for silicon, the invention uses solution casting or spin-coating of organic semiconductor precursors followed by mild thermal treatment, replacing complex mechanical fabrication systems with simpler chemical deposition processes
3Ease of manufacture
If existing organic semiconductor materials are used, then low processing temperature is achieved, but the response speed and mobility are insufficient for practical applications
Solution Approach 1:
The patent systematically varies molecular structure parameters of organic semiconductors, specifically incorporating fused ring systems (anthracene, phenanthrene, chrysene) with controlled substituent patterns to enhance charge carrier mobility from conventional values (<10^-5 cm²/Vs) to high values (>10^-3 cm²/Vs), while maintaining compatibility with low-temperature solution processing
Solution Approach 2:
The patent performs preliminary molecular design and synthesis of optimized organic semiconductor compounds before device fabrication. The semiconductor materials are pre-synthesized with optimized molecular structures that inherently provide high mobility, eliminating the need for post-fabrication performance enhancement and enabling direct use in high-performance TFT devices
Data Source
AI summary
A compound for an organic thin film transistor having a structure represented by the following formula (1):wherein R1 and R2, and R3 and R4 are respectively combined with each other to form an aromatic hydrocarbon ring having 6 to 60 carbon atoms or an aromatic heterocyclic ring having 3 to 60 carbon atoms; the ring being fused to the ring to which the groups are bonded, whereby the structure of the formula (1) has 5 or more aromatic rings that are fused; and the fused rings formed by R1 and R2, and R3 and R4 each may have a substituent.