Graphene-Based Light-Emitting Element with Upward-Grown Microstructures

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Solution Overview

Problem

Conventional light-emitting diodes (LEDs) face challenges with sapphire substrates due to low thermal conductivity and difficulty in processing, while graphene's chemical stability makes it hard to grow microstructures or thin-films effectively.

Innovation Solution

A light-emitting element is created using a carbon layer with graphene, where microstructures are grown upward, covered with a thin-film layer, and a light-emitting structure layer is formed on top, enabling high-efficiency LED production with excellent electrical and optical properties, and facilitating substrate transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If sapphire substrate is used, then light transmission property and mechanical strength are improved, but thermal conductivity and ease of processing deteriorate

Engineering Contradiction:

Improvemechanical strengthVSAvoidease of processing

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent introduces a carbon layer as an intermediary between the sapphire substrate and the light-emitting layer. This carbon layer serves as a mediator that enables effective thermal management and facilitates processing while maintaining the mechanical strength provided by the sapphire substrate. The carbon layer acts as a buffer that resolves the contradiction between the substrate's inherent strength and the difficulty of direct processing.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Illumination intensity

If sapphire substrate is used, then light transmission property is improved, but thermal conductivity deteriorates

Engineering Contradiction:

Improvelight transmission propertyVSAvoidthermal conductivity

Core Design Contradiction:

Illumination intensityVSTemperature

Solution Approach 1:

The patent segments the thermal management function from the optical function by introducing a dedicated carbon layer. The sapphire substrate maintains its role for light transmission, while the carbon layer specifically handles thermal conductivity. This segmentation allows each layer to optimize its respective function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The carbon layer acts as a thermal intermediary that conducts heat away from the light-emitting region while allowing light to pass through the sapphire substrate. This mediator resolves the contradiction by providing a dedicated thermal management path separate from the optical path.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If graphene is used, then thermal and electrical conductivity are improved, but ease of growing microstructures deteriorates

Engineering Contradiction:

Improvethermal and electrical conductivityVSAvoidease of growing microstructures

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by treating the graphene surface with oxygen plasma before growing microstructures. This pre-treatment modifies the graphene surface properties, making it more receptive to microstructure growth while preserving the excellent electrical and thermal conductivity of graphene. The preliminary surface modification resolves the contradiction between maintaining conductivity and enabling microstructure formation.

Inventive Principle:

Principle #10Preliminary 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

This approach allows for high-efficiency light-emitting elements with improved thermal and electrical conductivity, reduced contact resistance, and flexibility in substrate selection, overcoming the limitations of sapphire substrates and graphene's reactivity.

Implementation Method 1

graphene has excellent thermal and electrical conductivity

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

graphene has excellent electrical conductivity

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

technology for growing graphene on a large substrate having a size of to about 30 inches using chemical vapor deposition (CVD) has emerged

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 4

An LED is a device that emits light due to electron-hole pairs near a p-n junction or in an active layer by flowing current through a terminal of a compound semiconductor

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS9166101B2Light-emitting element and method for manufacturing same

Publication Date: 2015.10.20 SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION

AI summary

The present invention provides a light-emitting element comprising: a carbon layer comprising a graphene; a plurality of fine structures having grown toward the upper side of the carbon layer; a thin film layer for coating the fine structures; and a light-emitting structure layer formed on the thin film layer.