Polycyclic Aromatic Hydrocarbon Copolymers for Flexible Electronics
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Solution Overview
Problem
Existing organic semiconductor compositions face limitations in mobility values, requiring polymers with permittivity less than 3.3 and using undesirable chlorinated solvents, which are not industrially acceptable and environmentally friendly, especially for producing top gate OFETs with long channel lengths and bottom gate TFTs.
Innovation Solution
Development of polycyclic aromatic hydrocarbon copolymers (PAHCs) that are soluble in non-chlorinated solvents, offering tunable permittivity and high mobility, suitable for both top gate and bottom gate TFTs, and enabling high solids loadings and flexibility in electronic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polymer binders with permittivity greater than 3.3 are used, then the formulations can be processed more easily and provide better mechanical properties, but the mobility values of the OFET device are significantly reduced
Solution Approach 1:
The invention changes the permittivity parameter of the polymer binder from the conventional limit of <3.3 to >3.3, demonstrating that higher permittivity materials can be used without sacrificing device performance. This parameter change resolves the contradiction by expanding the acceptable range of permittivity values while maintaining high mobility
Solution Approach 2:
The invention uses composite materials by combining polycyclic aromatic hydrocarbon copolymers with high-permittivity polymer binders. This composite approach allows the formulation to benefit from both the processability of high-permittivity polymers and the high mobility of polycyclic aromatic hydrocarbons, resolving the contradiction between ease of manufacture and device reliability
2Reliability
If chlorinated solvents like 1,2-dichlorobenzene are used, then the highest performance semiconductor compositions with mobilities ~1.0 cm²V⁻¹s⁻¹ can be achieved, but the solvents are environmentally damaging and not industrially acceptable
Solution Approach 1:
The invention converts the previously harmful effect of using non-chlorinated solvents (which resulted in lower mobility) into a benefit by developing formulations that achieve high mobility without chlorinated solvents. The polycyclic aromatic hydrocarbon copolymers enable this conversion, allowing environmentally benign processing while maintaining high device performance
Solution Approach 2:
The invention changes the solvent composition parameter from chlorinated to non-chlorinated solvents, fundamentally altering the processing chemistry. This parameter change is made possible by the specific molecular structure of the polycyclic aromatic hydrocarbon copolymers, which maintain high mobility even when processed with environmentally friendly solvents
3Reliability
If small molecule semiconductors are used, then high mobility can be achieved, but the deposited layers are brittle and lack flexibility
Solution Approach 1:
The invention creates composite semiconductor materials by combining polycyclic aromatic hydrocarbon copolymers with high-permittivity polymer binders. This composite structure provides both the high mobility of crystalline semiconductor phases and the flexibility of polymer matrices, resolving the contradiction between reliability and mechanical strength
Solution Approach 2:
The invention applies local quality by creating regions of high crystallinity within the polymer matrix where charge transport occurs, while the surrounding polymer provides mechanical flexibility. This local differentiation allows the material to exhibit high mobility in the crystalline domains while maintaining overall flexibility of the deposited layer
Data Source
AI summary
The present invention relates to organic copolymers and organic semiconducting compositions comprising these materials, including layers and devices comprising such organic semiconductor compositions. The invention is also concerned with methods of preparing such organic semiconductor compositions and layers and uses thereof. The invention has application in the field of printed electronics and is particularly useful as a semiconducting material for use in formulations for organic thin film transistor (OTFT) backplanes for displays, integrated circuits, organic light emitting diodes (OLEDs), photodetectors, organic photovoltaic (OPV) cells, sensors, memory elements and logic circuits.