Silver Nanowire Patterning via Iodine and Thiosulfate Treatment
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Solution Overview
Problem
Existing light transmitting electrically conductive members with embedded silver nanowires face challenges in patterning, as oxidizing agents used to convert conductive regions to non-conductive regions often result in degraded optical characteristics due to incomplete permeation and surface exposure of metal oxides, leading to haze and reduced transparency.
Innovation Solution
A method involving an electrically conductive layer with an overcoat layer and silver nanowires, where silver nanowires in non-conductive regions are partially iodized using an iodine solution, and excess silver iodide is removed with a thiosulfate solution, maintaining high transparency by minimizing surface exposure of silver iodide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxidizing agents are used to convert silver nanowires to non-conductive regions, then electrical conductivity is reduced in patterned areas, but optical characteristics are degraded due to surface exposure of metal oxides
Solution Approach 1:
The patent changes the chemical parameter by using iodine (a different type of chemical agent) instead of traditional oxidizing agents. This parameter change allows the silver nanowires to be converted to silver iodide, which has different optical properties - specifically, it reduces surface exposure and maintains transparency while still achieving the desired electrical insulation.
Solution Approach 2:
The patent uses a two-step process where first iodine is applied to convert silver nanowires to silver iodide, and then excess silver iodide on the surface is removed. This copying approach achieves the electrical insulation effect while eliminating the optical degradation caused by surface exposure of metal compounds.
2Reliability
If silver nanowires are partially exposed to the surface for ensuring electrical conductivity, then electrical connection is improved, but optical characteristics are degraded when oxidizing agents are applied
Solution Approach 1:
The patent extracts or removes the harmful component (excess silver iodide on the surface) after the beneficial transformation has occurred. By removing only the surface-exposed silver iodide while maintaining the converted silver nanowires within the overcoat layer, the patent achieves both electrical insulation and optical transparency.
3Manufacturing precision
If traditional oxidizing agents like hypochlorite or TCNQ are used, then non-conductive regions are formed, but permeation into the overcoat layer is insufficient for precise patterning
Solution Approach 1:
The patent changes the chemical parameter by substituting traditional oxidizing agents with iodine. This parameter change improves permeation into the overcoat layer, enabling precise patterning while maintaining ease of manufacture. The iodine solution effectively penetrates the overcoat layer to convert silver nanowires throughout the required depth.
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 approach effectively increases surface resistivity in non-conductive regions without significantly altering light transmittance, reducing haze and maintaining high transparency by controlling the presence of silver iodide on the surface.
Implementation Method 1
silver nanowires in non-conductive regions are partially iodized using an iodine solution
Implementation Method 2
excess silver iodide is removed with a thiosulfate solution
Data Source
AI summary
A method for patterning a light transmitting electrically conductive member uses a light transmitting laminate material in which an electrically conductive layer including an overcoat layer and silver nanowires embedded therein is formed on a surface of a light transmitting base film and includes a step of treating a surface of the electrically conductive layer which is not covered with a resist layer using an iodine solution to at least partially iodize the silver nanowires and a step of applying a thiosulfate solution to the surface of the electrically conductive layer which is not covered with the resist layer to remove a silver iodide exposed to a surface of the overcoat layer. Since a white cloudy or a whitened silver iodide is removed, the optical transmission characteristics of the non-electrically conductive region can be improved.