Pulse Laser Patterning of Graphene Transparent Electrodes

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Solution Overview

Problem

Current methods for patterning graphene layers for transparent electrodes face challenges such as weak adhesiveness between graphene and polymer substrates, increased contact resistance, and damage to substrates during etching, which affect the transmittance and surface resistance of the electrodes.

Innovation Solution

A method using a pulse laser system to pattern holes in a graphene layer on a flexible transparent substrate, adjusting scanning speed and repetition rate, and performing chemical doping to reduce surface resistance while avoiding photoresist processes that can damage the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a photo process using photosensitive photoresist is used to pattern graphene holes, then hole patterns can be formed on graphene, but the graphene may be torn due to weak adhesiveness between the transparent polymer substrate and graphene during photoresist removing process

Engineering Contradiction:

Improvehole pattern formationVSAvoidgraphene integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent removes the photoresist step entirely from the process, extracting the harmful element that causes graphene tearing. Instead of using photoresist to define hole patterns, the invention uses direct laser irradiation to pattern the graphene, eliminating the adhesion problem between photoresist and graphene that causes tearing during removal.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/chemical photoresist process with a direct energy-based laser processing method. Instead of using chemical photoresist that requires mechanical removal, the invention uses laser energy to directly ablate or modify the graphene in the desired hole pattern areas, substituting a problematic mechanical-chemical process with a more reliable energy-based process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If the RIE method is used and oxygen plasma is applied for etching, then hole patterns can be formed on graphene, but the transparent polymer substrate may be damaged as not only graphene but also the transparent polymer substrate is etched

Engineering Contradiction:

Improvehole pattern formationVSAvoidsubstrate damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by using laser irradiation that can be precisely controlled to affect only the graphene layer at specific locations. The laser energy is concentrated exactly where hole patterns are needed, creating localized modification or ablation of the graphene without affecting the surrounding substrate. This selective local processing prevents the widespread substrate damage that occurs with oxygen plasma etching.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent substitutes the chemical oxygen plasma etching process with a controlled laser energy process. Instead of using reactive oxygen species that non-selectively etch both graphene and the polymer substrate, the invention uses laser energy that can be precisely controlled to interact only with the graphene layer, replacing a harmful chemical process with a more selective energy-based process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Illumination intensity

If many holes are made in a line in the graphene to increase light transmittance, then effective transmittance suitable for transparent electrode can be obtained, but the surface resistance of the graphene layer increases

Engineering Contradiction:

Improvelight transmittanceVSAvoidsurface resistance

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent uses dynamic laser scanning to create hole patterns with optimized spacing and distribution. By controlling the laser scanning speed, repetition rate, and beam parameters, the invention dynamically adjusts the hole pattern characteristics to achieve the right balance between light transmittance and electrical conductivity. The laser method allows continuous adjustment of pattern parameters to optimize both optical and electrical properties simultaneously.

Inventive Principle:

Principle #15Dynamics

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 enhances light transmittance and maintains low surface resistance, preventing substrate damage and improving the processing efficiency of graphene electrodes without the need for photoresist processes.

Implementation Method 1

forming a plurality of hole patterns spaced apart from each other on the graphene layer by irradiating the pulse laser while the graphene layer is in motion

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS10124438B2Method of patterning graphene holes and method of fabricating graphene transparent electrode by using pulse laser

Publication Date: 2018.11.13 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of patterning holes includes placing a substrate on a stage of a laser system, the substrate having a graphene layer on a surface thereof, generating a pulse laser from the laser system, and forming a plurality of hole patterns spaced apart from each other on the graphene layer by irradiating the pulse laser while the graphene layer is in motion.