Conductive Ink Formulation for Transparent Electrodes
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Solution Overview
Problem
Existing methods for producing transparent conductive electrodes face challenges such as high cost, fragility, and rapid degradation due to the use of indium tin oxide (ITO) and alternative materials like copper nanowires, which are prone to oxidation, and require polymeric additives that reduce conductivity and transparency.
Innovation Solution
A method of producing a printable conductive ink using a mixture of amines and carboxylic acids to create a viscous liquid medium for dispersing conductive materials like silver nanowires, eliminating the need for polymeric additives and allowing for high-resolution printing of complex patterns without reducing conductivity or transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polymeric additives are used in conductive ink to aid printability and adhesion, then the ink becomes more printable and adheres better to substrates, but the conductivity and transparency of the electrode are reduced due to coating of conductive particles and increased percolation threshold
Solution Approach 1:
The patent removes polymeric additives from the conductive ink formulation entirely, extracting the harmful component that coated conductive particles and reduced conductivity. The ink achieves printability through the inherent properties of the conductive material dispersion in aqueous solvent without requiring polymeric binders or viscosity modifiers.
Solution Approach 2:
The patent changes the formulation parameters by using high-quality conductive materials with appropriate particle size distribution and surface properties that enable direct printing without polymeric additives. The conductive particles are engineered to provide both printability and high conductivity simultaneously.
2Ease of manufacture
If polymeric additives are used as viscosity modifiers in conductive ink, then the ink viscosity is improved for printing, but the amount of conductive material required increases to achieve similar conductivity, increasing cost and reducing transparency
Solution Approach 1:
The patent extracts polymeric viscosity modifiers from the formulation and replaces them with conductive particle dispersions in aqueous solvent that achieve appropriate viscosity through particle concentration and size distribution alone, eliminating the need for additional substances that would require higher conductive material loading.
3Reliability
If copper nanowires are used to create transparent electrodes with good flexibility and transmittance, then the electrode performance is improved, but the electrode quickly oxidizes when exposed to moisture and oxygen, significantly degrading electrical conductivity
Solution Approach 1:
The patent uses silver nanoparticles instead of copper nanowires, selecting a material that is more chemically stable and resistant to oxidation. While silver is more expensive than copper, the superior stability prevents rapid degradation, and the nanoparticle formulation allows for lower concentrations to achieve the required conductivity, offsetting some of the material cost difference.
Solution Approach 2:
The patent creates a composite conductive ink formulation combining silver nanoparticles with a specific binder system that provides both chemical stability and electrical conductivity. The composite structure protects the conductive particles from oxidation while maintaining high conductivity and flexibility.
4Reliability
If vacuum deposition is used to deposit ITO for transparent electrodes, then high transparency and conductivity are achieved, but the process is expensive, prone to defects, and not conducive to forming patterns requiring complex patterning processes
Solution Approach 1:
The patent replaces the mechanical vacuum deposition process with a printing process that uses inkjet or similar printing technology to deposit conductive ink patterns directly. This substitution eliminates the need for complex vacuum chambers, heating elements, and photolithography steps, allowing for direct patterning of complex electrode designs in a single step.
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
The solution enables the production of stable, cost-effective, and durable transparent electrodes with improved conductivity and transparency, as the ink can be printed without polymeric additives, reducing the need for high conductive material concentrations and avoiding surface insulation that degrades conductivity.
Implementation Method 1
forming a mixture of a first composition, comprising at least one amine, a second composition, comprising at least one carboxylic acid, and a conductive material
Implementation Method 2
dispersing conductive materials like silver nanowires
Data Source
AI summary
A method of forming transparent electrodes using printable conductive ink containing conductive materials dispersed in a viscous liquid which upon printing and thermal treatment will vaporise fully leaving behind the conductive material only. The viscous liquid acts as a medium by which conductive material dispersions are made processable for use in various printing techniques, allowing conductive patterns to be printed onto substrates (e.g. plastics, glass, metals, ceramics).