Silver Nanoparticle Ink for Conductive Patterns on Polymers
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Solution Overview
Problem
Current methods for fabricating electrically-conductive silver patterns in electronic devices are time-consuming and expensive, and they require complex processes such as photocuring or high-temperature sintering, which are not compatible with polymeric substrates, and there is a need for simpler and less expensive compositions and methods for generating silver nanoparticles for high-speed manufacturing and electroless plating processes.
Innovation Solution
A non-aqueous silver precursor composition containing reducible silver ions and cellulosic polymers is used to generate silver nanoparticles, which are then deposited into patterns and electrolessly plated with copper, avoiding the need for photocuring and complex dispersion processes, and providing stable and high-conductivity silver patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photolithographic and electroless techniques are used to fabricate silver-containing electronics, then electrical conductivity is achieved, but the process becomes time-consuming and expensive
Solution Approach 1:
The patent extracts the silver nanoparticles from complex photolithographic processes and formulates them into a simple ink composition that can be directly printed. The silver nanoparticles are separated from the need for photomasks, chemical development, and multiple processing steps, allowing direct digital printing onto polymeric substrates while maintaining electrical conductivity and reducing manufacturing time and cost.
Solution Approach 2:
The patent replaces the mechanical and chemical complexity of photolithographic systems (photomasks, UV exposure, chemical developers) with a simplified thermal processing system. The silver nanoparticle ink is applied and then activated by simple heating to fuse the particles and establish electrical conductivity, eliminating the need for complex photolithographic equipment and reducing process time.
2Reliability
If high-temperature sintering is used to increase electrical conductivity of printed silver inks, then conductivity improves, but compatibility with polymeric substrates is lost
Solution Approach 1:
The patent changes the processing temperature parameter from high-temperature sintering (typically >800°C for traditional silver inks) to low-temperature thermal processing (50-150°C) suitable for polymeric substrates. This is achieved by using organic solvents that evaporate at low temperatures and binders that become conductive at low temperatures, allowing the silver nanoparticles to form conductive pathways without degrading the polymeric substrate.
Solution Approach 2:
The patent creates a composite ink formulation combining silver nanoparticles with organic solvents and polymeric binders that work together at low temperatures. The organic components facilitate nanoparticle dispersion and provide a matrix that enables conductivity development at temperatures compatible with polymeric substrates, creating a composite material system that achieves both conductivity and substrate compatibility.
3Reliability
If silver compounds are used as metallic patterns in electronic devices, then electrical conductivity is achieved, but complex fabrication processes are required
Solution Approach 1:
The patent segments the silver-containing composition into pre-formed silver nanoparticles that are already in their conductive metallic state within the ink formulation. This eliminates the need for subsequent reduction steps or chemical transformations that would be required if using silver compounds, simplifying the fabrication process while maintaining electrical conductivity.
Solution Approach 2:
The patent performs the silver nanoparticle formation action in advance during ink preparation, rather than during the device fabrication process. The silver nanoparticles are pre-synthesized and stabilized in the ink formulation, so that when the ink is printed and thermally processed, the nanoparticles are already formed and ready to create conductive pathways, eliminating complex in-process silver formation steps.
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 allows for the simple and cost-effective generation of silver nanoparticles with long-term stability and high electrical conductivity, enabling efficient electroless plating of copper patterns on polymeric substrates, reducing manufacturing costs and simplifying the process while maintaining high conductivity.
Implementation Method 1
a non-aqueous silver precursor composition containing reducible silver ions and cellulosic polymers is used to generate silver nanoparticles
Implementation Method 2
silver has desirable electrical and thermal conductivity, catalytic properties, and antimicrobial behavior
Data Source
AI summary
An article has a substrate and a pattern of a dry silver nanoparticle-containing composition comprising at least 20 weight % of one or more (a) polymers, that are cellulosic polymers; (d) silver nanoparticles having a mean particle size of 25-750 nm and present in an amount of 0.1-400 weight %, based on the total weight of the one or more (a) polymers; and (e) carbon black in an amount of 5-50 weight %, based on the total weight of the one or more (a) polymers. Such patterns can have multiple fine lines of any geometric arrangement. The article can have multiple patterns of this type, and each pattern can be electrolessly plated with a suitable metal such as copper to provide electrically-conductive product articles.