Organic Thin Film Transistor Pyrene Derivative Ohmic Contact
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Solution Overview
Problem
The performance of organic thin film transistors is limited by the high cost and processing difficulties of using noble metals with high work functions for source and drain electrodes, which restrict their application in electronic devices.
Innovation Solution
An organic thin film transistor is developed with an organic layer comprising a specific compound that facilitates ohmic contact between the semi-conducting layer and electrodes, allowing the use of less expensive materials with low work functions for the source and drain electrodes, such as aluminum, while maintaining effective charge carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noble metals with high work functions (Pd, Pt, Au) are used for source/drain electrodes, then electrical contact performance is improved, but manufacturing cost increases and processing becomes more difficult
Solution Approach 1:
The patent introduces an organic compound layer (Formula 1) as an intermediary between the electrode and the semiconductor layer. This intermediary layer has specific molecular structure features (pyrene core with electron-withdrawing groups) that enable it to mediate charge carrier injection, allowing low work function metals to achieve good electrical contact without requiring expensive noble metals
Solution Approach 2:
The patent changes the chemical and electronic parameters of the electrode interface by introducing the organic compound layer with specific HOMO/LUMO energy levels. This layer modifies the work function effectively and creates favorable energy level alignment for charge carrier injection, transforming the electrical contact properties without changing the base electrode material
2Ease of manufacture
If inexpensive materials with low work functions are used for source/drain electrodes, then manufacturing cost decreases, but electrical contact performance deteriorates
Solution Approach 1:
The organic compound layer serves as a mediator that bridges the mismatch between low work function metals and the semiconductor layer. It provides a pathway for efficient charge carrier injection by having appropriate energy levels (HOMO and LUMO) that align well with the semiconductor, thus compensating for the low work function of inexpensive electrode materials
Solution Approach 2:
The electrode structure becomes a composite system consisting of the metal electrode plus the organic compound layer. This composite structure combines the low cost of aluminum or other inexpensive metals with the excellent charge carrier injection properties of the organic compound, achieving both cost reduction and maintained performance
Data Source
AI summary
The present invention relates to an organic thin film transistor which includes an organic layer comprising an organic compound facilitating the ohmic contact between a semi-conducting layer and electrodes and serving as the semi-conducting layer.The organic thin film transistor according to the present invention has excellent electric contact between the semiconductor layer and the source electrode/drain electrode, and thus can be widely used as components for electric/electronic devices. As a result, as the materials for the source electrode or the drain electrode in the organic thin film transistor, materials which are less expensive and excellent in processibility though they have a low work function as the materials can be used.