Silver Nanowire Transparent Electrode for Low-Temperature Conductivity

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Solution Overview

Problem

Existing transparent electrodes for solar cells and other applications face challenges in achieving low sheet resistance, high transmittance, and flexibility while being produced at low temperatures.

Innovation Solution

A transparent electrode composed of a network of silver nanowires with a minimum radius of curvature of 2 µm or less and a bending angle of 90° or more, combined with a compound having an alkynyl group and a hydroxy group, which facilitates bonding between silver nanowires and reduces electrical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ITO film is formed by sputtering at high temperature or high-temperature annealing, then conductivity is improved, but application to organic material becomes impossible

Engineering Contradiction:
ImproveconductivityVSAvoidapplication to organic material
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention changes the temperature parameter from high temperature (required for ITO sputtering) to low temperature (below 100°C) by using a different material system (silver nanowires with organic compound) and deposition method (solution processing), enabling compatibility with organic substrates while maintaining conductivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite structure combining silver nanowires with an organic compound having alkynyl and hydroxy groups, where the silver nanowire network provides conductivity and the organic compound provides adhesion to the substrate, achieving both low-temperature processing and high conductivity

Inventive Principle:
Principle #40Composite materials

2Temperature

If silver nanowires are used as transparent electrode, then low temperature deposition is achieved, but light transmittance and conductivity need further improvement

Engineering Contradiction:
Improvedeposition temperatureVSAvoidlight transmittance and conductivity
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The invention optimizes the local properties of silver nanowires by controlling their diameter (20-50 nm) and creating a network structure with specific curvature radius (2 µm or less), where the nanoscale dimensions and curved configurations improve both light transmittance and electrical conductivity simultaneously

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the physical and chemical parameters of the silver nanowire network by introducing organic compounds with specific functional groups (alkynyl and hydroxy), which modify the inter-wire spacing and contact resistance, thereby improving conductivity without compromising transmittance

Inventive Principle:
Principle #35Parameter changes

3Reliability

If transparent electrode with low sheet resistance is achieved, then conductivity is improved, but flexibility and light transmittance may be compromised

Engineering Contradiction:
Improvesheet resistanceVSAvoidflexibility and light transmittance
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention introduces curvature into the silver nanowire network by specifying a minimum radius of curvature of 2 µm or less, which allows the nanowires to pack more efficiently and form better electrical contacts while maintaining flexibility and optical transparency through the curved, non-linear configuration

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention uses a thin film network of silver nanowires with diameter 20-50 nm arranged in a curved configuration, creating a flexible, transparent structure that achieves low sheet resistance through the optimized network geometry rather than through thick, rigid metal layers

Inventive Principle:
Principle #30Flexible shells and thin films

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 achieves a low sheet resistance of 6 to 10 Ω/□, high light transmittance, and flexibility, enabling the production of efficient and durable flexible solar cells and other electronic devices.

Implementation Method 1

a transparent electrode including a compound having a boiling point of 160°C or lower and an alkynyl group and a hydroxy group

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

heating and drying the applied substrate

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4553858A1Transparent electrode, manufacturing method therefor, and electronic device employing transparent electrode
Publication Date: 2025.05.14 KK TOSHIBA
  • EP4553858A1 patent drawingFigure 1~2(B)
  • EP4553858A1 patent drawingFigure 3
  • EP4553858A1 patent drawingFigure 4(A)~4(C)

AI summary

Provided are a transparent electrode that can be manufactured at a low temperature, has low sheet resistance, is highly transmissive and lightweight, and allows realization of a flexible solar cell, large-area illumination, and the like, a preparing method of the transparent electrode, and an electronic device using the transparent electrode. A transparent electrode according to an embodiment has a network of silver nanowires. The transparent electrode includes a silver nanowire having a minimum curvature radius r of a curve of 2 µm or less and a bending angle Θ of 90° or more, and a compound having a boiling point of 160°C or lower and an alkynyl group and a hydroxy group.