Silver Nanowire Patterning via Selective Halide Etching
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Solution Overview
Problem
Existing methods for patterning electrically conductive layers based on silver nanowires either result in significant changes to sheet resistance or compromise the optical appearance, making it difficult to achieve transparent and structured conductive layers with desired resistance values and color homogeneity.
Innovation Solution
A method involving coating a substrate with a composition of silver nanowires and a solvent, followed by partial solvent removal and selective etching with an organic compound capable of releasing chlorine, bromine, or iodine, to create patterned structures with significant resistance differences while maintaining optical homogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If silver nanowires are removed from certain areas by washing with water, then patterned structure is obtained, but inhomogeneous optical properties result
Solution Approach 1:
The patent extracts silver nanowires from specific areas using a selective etching process. The etching solution contains halide ions (Cl-, Br-, or I-) that selectively remove silver nanowires from patterned areas while leaving other areas intact, achieving the desired patterned structure with homogeneous optical properties.
Solution Approach 2:
The patent applies different treatments to different areas of the substrate. The etching solution is applied selectively to specific regions, creating local differences in silver nanowire presence while maintaining uniform optical appearance across the entire surface.
2Shape
If etching solutions containing halide and oxidizer are used, then silver nanowires can be etched, but colour of the coating is compromised
Solution Approach 1:
The patent changes the chemical parameters of the etching solution by selecting specific halide ions (Cl-, Br-, or I-) and controlling their concentration (0.01-10 wt%). This allows selective etching of silver nanowires while minimizing color changes in the coating, achieving a balance between etching effectiveness and optical appearance.
Solution Approach 2:
The patent uses simple, inexpensive halide salts (such as NaCl, KBr, or KI) as etching agents. These readily available compounds provide effective etching without the need for complex or expensive reagents, and they do not cause significant color degradation.
3Reliability
If conventional etching substances are used, then conductivity reduction is achieved, but sheet resistance difference is insufficient
Solution Approach 1:
The patent optimizes the etching parameters by using halide ions at controlled concentrations (0.01-10 wt%) to achieve precise control over silver nanowire removal. This results in well-differentiated sheet resistance values between etched and non-etched areas, with etched areas reaching at least 1×10^6 Ω/square while non-etched areas maintain preferably not more than 250 Ω/square.
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 method achieves transparent, structured electrically conductive layers with non-etched areas having a surface resistance of up to 250 Ω/square and etched areas exceeding 1×10^6 Ω/square, along with minimal color difference, addressing the limitations of prior art.
Implementation Method 1
an organic compound capable of releasing chlorine, bromine or iodine
Implementation Method 2
an etching composition comprises an organic compound capable of releasing chlorine, bromine or iodine
Data Source
AI summary
The present invention relates to the production of a layer structure, comprising the following process steps:i) coating a substrate with a composition at least comprising silver nanowires and a solvent;ii) at least partial removal of the solvent, thereby obtaining a substrate that is coated with an electrically conductive layer, the electrically conductive layer at least comprising the silver nanowires;iii) bringing into contact selected areas of the electrically conductive layer with an etching composition, thereby reducing the conductivity of the electrically conductive layer in these selected areas, wherein the etching composition comprises an organic compound capable of releasing chlorine, bromine or iodine, a compound containing hypochloride, a compound containing hypo-bromide or a mixture of at least two of these compounds.The invention also relates to a layer structure obtainable by this method, a layer structure, the use of a layer structure, an electronic component and the use of an organic compound.