Transparent Electrode with Carbon Nanotube Binder
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Solution Overview
Problem
Existing transparent electrodes for flexible displays face challenges with high process costs and short lifespan due to the fragility of indium tin oxide (ITO) thin films when bent or folded, and the adhesivity and environmental stability of carbon nanotube-based electrodes deteriorate at high temperatures.
Innovation Solution
A transparent electrode is developed with a conductive layer containing carbon nanotubes and a polymer binder, specifically using polycarbosilane, polysilane, polysiloxane, or polysilazane as the binder, combined with a conductive supplement like polyacetylene or polypyrrole, applied on a colorless transparent polyimide film substrate to enhance adhesion and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ITO thin film is used for transparent electrode, then transmissivity and conductivity are achieved, but process cost increases due to vacuum process requirement and lifespan decreases due to film fragility when bent or folded
Solution Approach 1:
The patent replaces expensive ITO materials with carbon nanotubes that can be deposited using low-cost solution processing methods, eliminating the need for expensive vacuum deposition equipment while achieving comparable or superior electrical and optical properties
Solution Approach 2:
The patent changes the physical state and processing parameters from vacuum-deposited thin films to solution-processable nanomaterials, enabling low-cost manufacturing through techniques like spin-coating, dip-coating, or spray deposition from liquid suspensions
2Duration of action of moving object
If ITO thin film is used for transparent electrode, then transmissivity and conductivity are achieved, but lifespan decreases due to film fragility when bent or folded
Solution Approach 1:
The patent employs carbon nanotubes that inherently possess flexibility and can withstand repeated bending and folding cycles without fracture, unlike brittle ITO films, enabling flexible and wearable electronic applications
Solution Approach 2:
The patent creates composite structures where carbon nanotubes are combined with conductive polymers or other matrix materials to form flexible transparent electrodes that maintain both mechanical durability and electrical conductivity under bending conditions
3Reliability
If carbon nanotubes are exposed to outside in conductive layer, then conductivity is achieved, but adhesivity and environmental stability deteriorate at high temperature
Solution Approach 1:
The patent introduces polymer binders or coupling agents as intermediary materials between carbon nanotubes and the substrate, enhancing adhesion while protecting the nanotubes from environmental degradation at high temperatures
Solution Approach 2:
The patent forms composite structures where carbon nanotubes are embedded in protective polymer matrices or coated with protective layers, simultaneously improving adhesivity to substrates and environmental stability against heat and moisture
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 solution provides a stable and environmentally robust transparent electrode with high transmittance (70% or more) and low surface resistance (1000 ohm/sq or less), maintaining performance even at elevated temperatures and during bending, thus addressing the issues of cost, fragility, and stability.
Implementation Method 1
a conductive layer which is formed on the substrate and includes a conductive material containing carbon nanotubes
Implementation Method 2
a conductive layer including a conductive material containing carbon nanotubes and a polymer binder is formed on a plastic substrate, so carbon nanotubes strongly adhere to the plastic substrate
Data Source
AI summary
Disclosed herein is a transparent electrode, including: a colorless transparent polyimide film substrate; and a conductive layer formed on the substrate and including a conductive material containing carbon nanotubes, wherein the conductive layer includes a polymer binder. The transparent electrode is advantageous in that carbon nanotubes strongly adhere to a plastic substrate and the transparent electrode exhibits environmental stability.