Organic Semiconductor Graphene Composite for Charge Mobility
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Solution Overview
Problem
Current organic thin film transistors (OTFTs) have limited charge carrier mobility, typically ranging from 0.1-0.2 cm2/V·sec, which restricts their applications due to plateaued performance over the last two decades, necessitating the development of new technologies to enhance mobility for broader applications.
Innovation Solution
The integration of an organic semiconductor and graphene in a composite semiconducting layer, where graphene is either alternated with or dispersed throughout the organic semiconductor layer, forming a percolation network and enhancing pi-pi stacking, thereby increasing charge transfer mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organic semiconductors are used in OTFTs, then the device structure is simple and manufacturing is easy, but the charge carrier mobility is limited to 0.1-0.2 cm2/V·sec
Solution Approach 1:
The patent applies composite materials by combining organic semiconductors with graphene to form a hybrid semiconducting layer. This composite structure leverages the beneficial properties of both materials: the organic semiconductor provides the necessary semiconducting characteristics while graphene contributes high charge carrier mobility and excellent electrical conductivity, thereby resolving the mobility limitation of conventional organic semiconductors without requiring complete structural redesign
Solution Approach 2:
The patent changes the physical and chemical parameters of the semiconducting layer by incorporating graphene at specific concentrations (typically 0.1-10 wt%) and controlling the morphology of the composite structure. This parameter modification enables the system to transition from the mobility plateau of conventional organic semiconductors to a new performance regime with enhanced charge carrier mobility while maintaining processability
2Reliability
If graphene is incorporated into the semiconducting layer to improve mobility, then charge transfer mobility increases, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-suspending graphene in the organic semiconductor solution before deposition, or by pre-forming graphene layers that are subsequently combined with organic semiconductor materials. This preliminary preparation enables the integration of graphene into the fabrication process without requiring additional complex manufacturing steps, as the graphene is incorporated during the standard solution processing or deposition sequence
Solution Approach 2:
The patent uses soluble salts as intermediaries to facilitate the incorporation of graphene into the organic semiconductor matrix. These salts act as mediators that enable uniform distribution and integration of graphene sheets within the organic semiconductor, simplifying the manufacturing process by providing a straightforward mixing and deposition approach rather than requiring complex alignment or assembly techniques
3Reliability
If higher graphene content is used to maximize mobility improvement, then charge transfer performance enhances, but the cost and material complexity increase
Solution Approach 1:
The patent optimizes the concentration parameter of graphene in the composite semiconducting layer, identifying a optimal range (typically 0.1-10 wt%) where mobility enhancement is maximized without excessive material usage. This parameter optimization reveals that beyond a certain threshold, additional graphene provides diminishing returns while increasing cost and processing complexity, enabling cost-effective high-performance devices
Solution Approach 2:
The patent ensures continuous and uniform distribution of graphene throughout the organic semiconductor matrix, maximizing the effectiveness of each graphene sheet. This continuous distribution approach ensures that the limited graphene material is utilized efficiently throughout the entire active area of the device, preventing waste and ensuring consistent performance across the device surface
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
This approach significantly increases the mobility of OTFTs beyond the conventional range, enabling broader applications by creating a synergistic effect that improves charge transfer and reduces defects in the pi-pi stacking array, while maintaining the flexibility and cost-effectiveness of graphene.
Implementation Method 1
graphene can form a percolation network within the semiconductor layer
Implementation Method 2
enhancing pi-pi stacking, thereby increasing charge transfer mobility
Data Source
AI summary
Electronic devices, such as organic thin film transistors, with improved mobility are disclosed. The semiconducting layer comprises layers or striations of an organic semiconductor and graphene, including alternating layers/striations of such materials. The organic semiconductor and graphene layers interact well together because both materials form lamellar sheets. The presence of graphene enhances mobility by correcting molecular packing defects in the organic semiconductor layers, and the conductivity of graphene can be controlled. Finally, both materials are flexible, allowing for flexible semiconductor layers and transistors.