Flash Reduction of Graphite Oxide Films for Conductive Graphene

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Solution Overview

Problem

The existing methods for reducing graphite oxide to graphene are challenging, especially when blended with polymer composites, as they require chemical reducing agents or high-temperature thermal treatments, which can be unstable and inefficient.

Innovation Solution

A flash reduction process using a single pulse of optical energy from a light source, such as a camera flash, is employed to instantaneously reduce graphite oxide films or composite films with polymers, achieving deoxygenation and expanding the material's thickness significantly, resulting in conductive graphene with high surface area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical reducing agents or high-temperature thermal treatments are used to reduce graphite oxide to graphene, then the reduction can be achieved, but the process becomes complex and unstable especially when blended with polymer composites

Engineering Contradiction:

Improvereduction stabilityVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces chemical reduction methods and high-temperature thermal treatments with a mechanical/physical flash photolysis method using intense light pulses. This substitution eliminates the need for complex chemical agents and high-temperature equipment, simplifying the overall process while improving reliability, especially for polymer composite blends where chemical and thermal methods cause instability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of reduction from chemical/thermal to optical energy input. By using intense light pulses with specific duration (nanosecond to microsecond range) and intensity, the reduction process achieves reliable results without the complexity and instability associated with conventional methods, particularly when polymers are present.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If conventional reduction methods are used, then graphene can be produced, but the process time is long and energy consumption is high

Engineering Contradiction:

Improvereduction speedVSAvoidenergy efficiency

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic flash photolysis using intense light pulses of nanosecond to microsecond duration. This periodic optical energy input efficiently drives the reduction reaction rapidly, achieving high productivity while maintaining energy efficiency because the energy is delivered in concentrated bursts rather than continuous input, reducing overall energy consumption compared to prolonged thermal or chemical methods.

Inventive Principle:

Principle #19Periodic action

3Adaptability or versatility

If graphite oxide is blended with polymer composites, then material versatility is improved, but the reducing agent cannot effectively react with GO due to polymer interference

Engineering Contradiction:

Improvecomposite compatibilityVSAvoidreduction efficiency

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces chemical reducing agents with optical energy (flash photolysis) to reduce graphite oxide within polymer composites. This substitution overcomes the polymer interference problem because light can penetrate the composite and directly energize the graphite oxide without being blocked or consumed by the polymer matrix, maintaining both versatility and manufacturing ease.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 process is chemical-free, rapid, and energy-efficient, producing graphene with conductivities comparable to those from conventional methods, while allowing for patterning and integration with polymers, enhancing electrical conductivity and surface area.

Implementation Method 1

delivering optical energy in a single pulse to the film of graphite oxide at a distance no more than 1.0 cm away from the film of graphite oxide to reduce the film of graphite oxide to a film of graphene

Methodology Applied

Scientific EffectPhotothermal heating: Photoacoustic Effect

Implementation Method 2

The period of time during which the film of graphite oxide is exposed to the single flash of light is less than 1.0×10−5 seconds, causing a photoacoustic response from the film of graphite oxide to the irradiation of the flash of the light

Methodology Applied

Scientific EffectPhotoacoustic response: Photoacoustic Effect

Data Source

PatentUS8968525B2Methods of flash reduction and patterning of graphite oxide and its polymer composites

Publication Date: 2015.03.03 NORTHWESTERN UNIV

AI summary

A method of reducing a film of graphite oxide. In one embodiment, the method includes the steps of providing a film of graphite oxide with a thickness d0; and delivering optical energy in a single pulse to the film of graphite oxide at a distance no more than 1.0 cm away from the film of graphite oxide to reduce the film of graphite oxide to a film of graphene with a thickness d, wherein the optical energy has a radiant exposure in the range of between 0.1 and 2 J/cm2, and wherein the thickness d is greater than the thickness d0. In one embodiment, the thickness d≧10×d0.