Stannous Alkoxide Complex for Silver Seed Formation
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Solution Overview
Problem
Current methods for producing electrically-conductive films for touch screen displays face challenges with Indium Tin Oxide (ITO) limitations, such as high cost, limited availability, low conductivity, and inflexibility, while existing silver-based solutions require complex dispersant systems and high silver particle concentrations to achieve uniform catalytic sites for electroless plating.
Innovation Solution
A non-aqueous stannous alkoxide composition is used to create silver particles in situ on a substrate, allowing for electroless plating of conductive metals without the need for dispersing silver particles, using a stannous alkoxide complex, photocurable components, and reducible silver ions, facilitating high-speed manufacturing processes like roll-to-roll operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver particles are dispersed in photocurable compositions to create conductive films, then electrical conductivity is improved, but the formulation and application process becomes complex requiring dispersants and careful processing
Solution Approach 1:
The invention extracts the silver particles from the photocurable composition entirely. Instead of dispersing silver particles in the coating material, the patent uses a separate silver salt layer that is applied independently and then reduced in situ. This eliminates the need for dispersants and complex formulation requirements while maintaining electrical conductivity.
Solution Approach 2:
The invention segments the conductive film formation into two distinct layers: a non-conductive polymer coating layer and a separate silver salt layer. This segmentation allows each layer to be optimized independently - the polymer layer for mechanical properties and the silver salt layer for electrical conductivity - without the formulation complexities of mixing silver particles throughout the entire coating.
2Manufacturing precision
If high concentrations of silver particles are used to achieve uniform catalytic sites, then electroless plating uniformity is improved, but material cost and processing complexity increase
Solution Approach 1:
The invention performs preliminary action by applying the silver salt layer before the reduction step. The silver salt is deposited uniformly across the substrate surface in advance, creating a consistent precursor distribution that ensures uniform catalytic sites after reduction, without requiring high concentrations or complex processing during the plating step.
Solution Approach 2:
The invention uses silver salt as a copy or precursor that reproduces the desired silver metal pattern. The silver salt layer is applied uniformly and then chemically reduced to create the conductive pattern, eliminating the need to physically handle and disperse actual silver particles while maintaining pattern uniformity.
3Reliability
If ITO coatings are used to create electrically-conductive films, then manufacturing process is established, but cost increases due to rare earth metal and limited availability
Solution Approach 1:
The invention replaces expensive ITO (indium tin oxide) with a cheaper silver-based system. Silver is more abundant and less costly than indium, a rare earth metal. The silver salt can be applied as a thin layer and reduced to provide adequate conductivity without requiring the expensive materials and vacuum deposition processes needed for ITO.
Solution Approach 2:
The invention changes the material parameter from ITO to silver salt, and changes the deposition method parameter from vacuum deposition to solution-based application. This allows the use of abundant, low-cost silver materials while achieving the required electrical conductivity through a simpler, more scalable process.
4Reliability
If vacuum deposition with high processing temperatures is used for ITO, then electrically-conductive layers are formed, but manufacturing flexibility and adaptability decrease
Solution Approach 1:
The invention replaces the vacuum deposition mechanical system with a solution-based chemical system. Instead of requiring vacuum chambers and high-temperature physical vapor deposition, the patent uses liquid or aerosol application of silver salt followed by chemical reduction, enabling flexible manufacturing including roll-to-roll processing and low-temperature fabrication.
Solution Approach 2:
The invention changes the processing temperature parameter from high temperature vacuum deposition to low temperature solution processing. This enables the use of temperature-sensitive substrates and flexible manufacturing methods that cannot accommodate the high temperatures and vacuum conditions required for traditional ITO deposition.
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 method generates uniform silver particles for electroless plating, enhancing conductivity and durability of the films, reducing manufacturing complexity and costs, and enabling flexible and efficient production of electrically-conductive patterns.
Implementation Method 1
contacting the first water-insoluble stannous alkoxide-containing pattern with reducible silver ions to chemically reduce the reducible silver ions and to provide silver(0) particles
Implementation Method 2
photocurable component (b), wherein: when photocurable component (b) is present, the water-insoluble stannous alkoxide composition further comprises photosensitizer component (d)
Data Source
AI summary
A method for forming an article, comprises providing a stannous alkoxide-containing pattern on a substrate. This stannous alkoxide-containing pattern is obtained from a non-aqueous stannous alkoxide composition that comprises component (a) comprising a water-insoluble stannous alkoxide complex comprising stannous ions, in an amount of at least 1 weight %, and a photocurable component (b), non-photocurable water-insoluble polymer component (c) having a molecular weight of at least 10,000, or both the photocurable component (b) and the non-photocurable water-insoluble polymer component (c). When photocurable component (b) is present, the water-insoluble stannous alkoxide composition further comprises photosensitizer component (d) that is different from all of components (a) through (c). The reducible silver ions can be chemically reduced to silver(0) particles as “seed” catalysts for electroless plating to form an electrically-conductive pattern corresponding to the water-insoluble stannous alkoxide-containing pattern.