Photosensitive Silver Ink for Room-Temperature Conductive Patterns
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Solution Overview
Problem
Current methods for fabricating electrically-conductive silver patterns and films are time-consuming and expensive, particularly when using photolithographic and electroless techniques, and they are not compatible with polymeric substrates, requiring high temperatures and sintering processes that can damage temperature-sensitive materials.
Innovation Solution
Development of a photosensitive composition containing a non-hydroxylic-solvent soluble silver complex with reducible silver ions complexed with α-oxy carboxylates and 5- or 6-membered N-heteroaromatic compounds, which can be rapidly converted to metallic silver at room temperature upon exposure to actinic radiation, allowing for direct digital printing and use on various substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithographic and electroless techniques are used to fabricate electrically-conductive silver patterns, then manufacturing precision and reliability are improved, but manufacturing time and cost increase significantly
Solution Approach 1:
The patent extracts the silver metal formation step from the traditional multi-step photolithographic process. By using a photosensitive silver complex that directly decomposes to metallic silver upon light exposure, the invention eliminates intermediate steps such as electroless plating and sintering, thereby reducing manufacturing time while maintaining pattern precision
Solution Approach 2:
The silver complex is pre-formulated with photosensitive properties and complexing agents during the ink preparation stage. This preliminary action ensures that upon light exposure, the silver ions are already positioned and chemically prepared to reduce to metallic silver rapidly, eliminating the need for time-consuming post-deposition processing steps
2Reliability
If high temperature sintering processes are used to create electrically-conductive silver films, then electrical conductivity is improved, but compatibility with polymeric substrates deteriorates due to temperature sensitivity
Solution Approach 1:
The patent changes the key parameter of silver metal formation from thermal (sintering temperature) to photochemical (light exposure). The photosensitive silver complex decomposes to metallic silver at room temperature when exposed to actinic radiation, eliminating the need for high temperature sintering and enabling processing on temperature-sensitive polymeric substrates while achieving adequate electrical conductivity
Solution Approach 2:
The patent replaces the thermal field (heat-based sintering process) with a photochemical field (light-based decomposition). The photosensitive complex uses light energy to drive the reduction of silver ions to metallic silver, substituting the mechanical/thermal process with an optical-chemical process that is gentler on substrates
3Ease of manufacture
If traditional silver inks are used for direct digital printing, then ease of manufacture is improved, but manufacturing precision and pattern quality deteriorate
Solution Approach 1:
The patent creates a composite photosensitive silver ink formulation containing silver ions, complexing agents (such as carboxylic acids, phenols, or amines), and photosensitizers. This composite material combines the ease of direct digital printing application with the precision of photochemical pattern formation, as the complexing agents stabilize the silver ions while the photosensitizers enable controlled decomposition to metallic silver upon light exposure
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
Enables rapid and cost-effective generation of electrically-conductive silver metal at room temperature, compatible with a wide range of substrates including plastics, metals, and glass, with improved stability and flexibility in manufacturing processes.
Implementation Method 1
a photosensitizer and a non-hydroxylic-solvent soluble silver complex containing reducible silver ions... which can be rapidly converted to metallic silver at room temperature upon exposure to actinic radiation
Data Source
AI summary
A precursor article has a substrate and a photosensitive thin film or a photosensitive thin film pattern on a supporting side. The photosensitive thin film and each photosensitive thin film patterns comprises a non-hydroxylic-solvent soluble silver complex that is represented by the following formula (I):(Ag+)a(L)b(P)c (I)wherein L represents an α-oxy carboxylate; P represents a 5- or 6-membered N-heteroaromatic compound; a is 1 or 2; b is 1 or 2; and c is 1, 2, 3, or 4, provided that when a is 1, b is 1, and when a is 2, b is 2. A photosensitizer that can either reduce the reducible silver ion or oxidize the α-oxy carboxylate having a reduction potential can also be present. Such precursor articles can be irradiated with UV-visible radiation to reduce the silver ions to provide electrically-conductive metallic silver in thin films or thin film patterns in product articles or devices.