Hybrid Transparent Electrode for Flexible Displays

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Solution Overview

Problem

Current transparent electrode materials, such as ITO, face challenges in achieving high flexibility, low sheet resistance, and high light transmittance, particularly for flexible electronic devices, due to limitations in mechanical characteristics and availability of indium.

Innovation Solution

A hybrid transparent electrode structure comprising a thermosetting copolymer layer with an aromatic moiety, a graphene layer, and an electrically conductive metal nanowire layer, which enhances binding properties and conductivity while maintaining high transmittance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ITO is used as transparent electrode material, then high light transmittance and low specific resistance are achieved, but flexibility is poor

Engineering Contradiction:

Improvelight transmittance and electrical conductivityVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent employs a composite transparent electrode consisting of multiple layers: a polymer substrate layer, a transparent conductive oxide layer (such as ITO or IZO), and a flexible support layer. This composite structure combines the high conductivity and transmittance of the TCO layer with the flexibility of the polymer and support layers, thereby achieving both electrical performance and mechanical flexibility that single-material electrodes cannot provide.

Inventive Principle:

Principle #40Composite materials

2Reliability

If ITO is used for transparent electrode, then high conductivity is achieved, but cost increases due to limited indium reserves

Engineering Contradiction:

Improveelectrical conductivityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent modifies the composition and structure of the transparent electrode by adjusting the thickness of the TCO layer, the type of TCO material used (e.g., switching from ITO to IZO or other indium-free alternatives), and the configuration of additional conductive layers. These parameter changes enable optimization of conductivity while reducing dependence on indium, thereby lowering material costs and improving manufacturability.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If a single-layer transparent electrode is used, then manufacturing is simple, but it cannot simultaneously achieve high flexibility, low sheet resistance, and high transmittance

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidcomprehensive performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent divides the transparent electrode into multiple functional layers, each optimized for a specific function: the polymer substrate provides flexibility and mechanical support, the TCO layer provides conductivity and transmittance, and the flexible support layer enhances bendability. This segmentation allows each layer to be independently optimized and manufactured using established processes, maintaining manufacturing simplicity while achieving superior overall performance.

Inventive Principle:

Principle #1Segmentation

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 hybrid structure achieves improved flexibility and reduced sheet resistance, with a resistance change rate of less than 60% after bending, and maintains high light transmittance, making it suitable for flexible electronic devices.

Implementation Method 1

a first layer including: a thermosetting copolymer including a first repeating unit having an aromatic moiety as a pendant group or incorporated in a backbone of the copolymer and a second repeating unit capable of lowering a curing temperature of the copolymer

Methodology Applied

Scientific EffectThermosetting polymerization: Photopolymerisation

Implementation Method 2

a second layer disposed directly on a first side of the first layer, wherein the second layer includes graphene

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

a third layer disposed on the second layer, wherein the third layer includes an electrically conductive metal nanowire

Methodology Applied

Scientific EffectMetallic conduction: Conduction (electrical)

Data Source

PatentUS11037696B2Transparent electrodes and electronic devices including the same

Publication Date: 2021.06.15 SAMSUNG ELECTRONICS CO LTD

AI summary

A transparent electrode including: a first layer including a thermosetting copolymer including a first repeating unit having an aromatic moiety as a pendant group or incorporated in a backbone of the copolymer and a second repeating unit capable of lowering a curing temperature, a combination of a first polymer including the first repeating unit and a second polymer including the second repeating unit, or a combination thereof; a second layer disposed directly on one side of the first layer, wherein the second layer includes graphene; and a third layer disposed on the second layer, wherein the third layer includes an electrically conductive metal nanowire.