Graphene Doping via Precursor Polymer Layer for Flexible Electrodes

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Solution Overview

Problem

Existing methods for doping graphene are limited by the inability to effectively modify substrates other than silicon oxide, leading to restricted doping effects and incompatibility with flexible devices due to the need for thick, transparent conductive oxide films.

Innovation Solution

A method involving the formation of a precursor polymer layer with a methyl group on a substrate, such as polyethylene terephthalate or triacetyl cellulose, using plasma enhanced chemical vapor deposition, which allows for graphene doping and enhances electrical properties, enabling the creation of a flexible, transparent composite electrode with reduced ITO usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thick transparent conductive oxide films are used to maintain transparency and conductivity requirements, then electrical properties are improved, but flexibility and surface roughness deteriorate

Engineering Contradiction:
Improveelectrical propertiesVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the material composition and thickness parameters of the transparent electrode by incorporating graphene (0.1-5 wt%) into the transparent conductive oxide film. This parameter modification allows achieving the required electrical properties with thinner films, thereby improving flexibility and reducing surface roughness while maintaining transparency and conductivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite transparent electrode structure by combining transparent conductive oxide with graphene. This composite material approach enables the electrode to achieve both the electrical conductivity of thick films and the flexibility of thin structures, resolving the contradiction between electrical performance and adaptability to flexible substrates

Inventive Principle:
Principle #40Composite materials

2Reliability

If substrate surface modification is performed using conventional methods (heat treatment or self-assembled monolayer), then doping effect is achieved, but compatibility with non-silicon oxide substrates deteriorates

Engineering Contradiction:
Improvedoping effectVSAvoidsubstrate compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the chemical composition parameters of the precursor polymer layer by incorporating nitrogen-containing groups and adjusting the C:N ratio (2:1 to 10:1). This parameter optimization enables effective graphene doping on diverse substrates including plastic, glass, and metal, achieving both strong doping effect and broad substrate compatibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a precursor polymer layer as an intermediary between the substrate and graphene. This intermediary layer mediates the doping process, allowing effective charge transfer to graphene while being compatible with various substrate types, thus resolving the limitation of conventional methods that work only on silicon oxide

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If precursor polymer layer with nitrogen is used for doping, then electrical conductivity is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the precursor polymer layer formation with the existing ITO deposition process by using the same vacuum chamber and sequential deposition approach. The precursor layer is formed first, then ITO is deposited on top in the same manufacturing cycle, eliminating the need for separate doping process equipment and reducing overall manufacturing complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent maintains continuous useful action by forming the precursor polymer layer and depositing ITO in a continuous vacuum process without breaking the vacuum chamber. This continuous manufacturing approach avoids additional processing steps and equipment transitions, improving electrical conductivity while keeping the manufacturing process simple and efficient

Inventive Principle:
Principle #20Continuity of useful action

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 improves graphene's electrical properties, allows for n-type or p-type doping, and forms a transparent composite electrode with low resistance, suitable for flexible displays, while maintaining doping effects and acting as a protective layer for graphene, thus overcoming limitations of traditional ITO layers.

Implementation Method 1

the formation of the precursor may be carried out using plasma enhanced chemical vapor deposition

Methodology Applied
Scientific EffectPlasma enhanced chemical vapor deposition: Plasma Enhanced Chemical Vapour Deposition

Data Source

PatentEP3284718B1Method for doping graphene, and graphene structure
Publication Date: 2020.06.10 LG ELECTRONICS INC
  • EP3284718B1 patent drawingFigure 1~2
  • EP3284718B1 patent drawingFigure 3~4
  • EP3284718B1 patent drawingFigure 5~6

AI summary

The present invention relates to graphene and, particularly, to a method for doping graphene using substrate surface modification, a method for manufacturing a graphene composite electrode using graphene and inorganic matter, and a graphene structure comprising the same. The method for doping graphene according to an embodiment of the present invention may comprise the steps of: forming, on a substrate, a precursor polymer layer for doping; and positioning graphene on the substrate on which the precursor polymer layer is formed. In addition, the method for manufacturing a graphene composite electrode according to an embodiment of the present invention may comprise the steps of: forming graphene on catalyst metal; forming a transparent conductive oxide on the graphene; crystallizing the transparent conductive oxide by applying heat of 150 °C or higher; and transferring, to a final substrate, a composite electrode consisting of the graphene and the transparent conductive oxide.