Graphene Conductive Ink Formulation for Tunable Printed Electronics
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Solution Overview
Problem
Current conductive inks for printed electronics are expensive, prone to agglomeration, and have viscosities and surface tensions that cannot be tuned for specific printing methods, leading to uneven components and poor adhesion to substrates, making large-scale production of durable and conductive printed components difficult.
Innovation Solution
A conductive ink comprising graphene sheets with high single-layer content and low oxygen content, combined with a polymeric binder, stabilizer, and solvent, which allows for tunable viscosity and surface tension, enabling even coating and improved adhesion, thermal stability, and flexibility, allowing for single-layer electronic circuit formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive inks are used, then printing can be performed, but the inks are expensive and prone to agglomeration
Solution Approach 1:
The patent changes the material composition parameters by using reduced graphene oxide instead of conventional silver or copper particles, and optimizes the oxygen content to 4-8% to prevent agglomeration while maintaining conductivity. This parameter change resolves the contradiction by providing a stable, non-agglomerating ink at lower cost
Solution Approach 2:
The patent creates a composite material system combining reduced graphene oxide with specific polymers (polyvinylpyrrolidone, polyacrylonitrile) and surfactants. This composite approach prevents agglomeration through synergistic interactions between components while maintaining electrical conductivity and reducing manufacturing cost compared to pure metal inks
2Adaptability or versatility
If conventional conductive inks are used, then conductivity can be achieved, but viscosities and surface tensions cannot be tuned for specific printing methods
Solution Approach 1:
The patent introduces dynamic tunability by adjusting the concentrations of polymers and surfactants in the ink formulation. This allows the viscosity and surface tension to be dynamically optimized for different printing methods (screen printing, inkjet, gravure) while maintaining component uniformity through stable colloidal suspension of the reduced graphene oxide
Solution Approach 2:
The patent changes the rheological parameters by incorporating adjustable concentrations of polyvinylpyrrolidone and polyacrylonitrile, enabling the ink to be tailored for specific printing methods. The oxygen content control (4-8%) also modifies surface properties to achieve desired surface tension while preventing agglomeration
3Strength
If conventional conductive inks are used, then coating can be performed, but adhesion to substrates is poor
Solution Approach 1:
The patent uses polymers (polyvinylpyrrolidone, polyacrylonitrile) as intermediary substances that bridge the reduced graphene oxide conductive particles and the substrate surface. These polymers provide adhesion promoters that enhance bonding strength while maintaining the simplicity of the printing process through a single-step coating operation
Data Source
AI summary
Provided herein are conductive inks and methods of formulation thereof, whose electric and mechanical properties (e.g. viscosity and surface tension) enable its use in a wide array of printing techniques. The outstanding conductivity, thermal stability, chemical stability, and flexibility of graphene in the inks herein enable the production of low-cost electronics with tunable electrochemical properties.