Heat dissipation remains a key challenge to be addressed, determining the performance and durability of smart electronic devices. Graphene reinforced metal matrix composites have been extensively studied as a thermal management material due to their high thermal conductivity and low coefficient of thermal expansion. The emphasis of this review is pivoted on the thermal conductivity enhancement of graphene reinforced Cu matrix composites developed in the recent literature. An overview of factors affecting thermal conductivity of composite namely defect processing route, density, graphene derivative, lateral size, concentration, alignment, graphene/matrix interfacial bonding and graphene modification are discussed. An extensive weightage is given to the processing route as it is the most influential factor in determining the enhancement efficiency. Furthermore, graphene based functional products such as heat spreader and heat sink developed for heat dissipation of electronic devices are also reviewed. Finally, the development and outlook for graphene based Cu composites are presented.

SEM image of uncoated GNPs, (b and d) SEM of Ag coated GNPs, (e and f) SEM of uncoated and Ag coated Alumina powder respectively

Graphene has excellent mechanical, electrical, and thermal properties which makes it a suitable candidate for various industrial applications [33]. Due to these properties, graphene has an edge over other carbonaceous materials such as graphite, diamond, and carbon nanotube. In order to get the advantage of these properties industrially for commercial applications, the synthesis of high quality graphene at a massive scale is highly desired, which is a challenging task. In order to overcome this challenge, several synthesis strategies have been proposed, and a few of these have already been put in action by various manufacturers [34]. Moreover, the incorporation of graphene in metal matrix composites has enhanced the thermophysical characteristics, elastic modulus, tensile strength and wear resistance of composites as compared to monolithic metals [35].

TC of graphene flake as a function of temperature for varying flake lengths

Advancement in Thermal Management Materials: The article highlights the significant improvement in thermal conductivity and thermal management capabilities when using graphene-reinforced composites over traditional metal films. This advancement addresses a critical need in the electronics industry, where heat dissipation is a major challenge due to miniaturization.

Scientific and Technical Insights: By reviewing the state-of-the-art research on Gr CuMCs, the article provides a comprehensive understanding of the factors affecting thermal conductivity enhancement (TCE). This includes defect density, graphene derivative type, size, concentration, alignment, interfacial bonding, and reinforcement modification.

Enhanced Device Performance and Longevity: By improving heat dissipation, Gr CuMCs can significantly enhance the performance and lifespan of high-performance electronic devices, including laptops, smartphones, smartwatches, and smart glasses. This benefit is crucial for maintaining device reliability and user satisfaction.

Miniaturization Support: The use of Gr CuMCs supports the trend of device miniaturization without compromising thermal management. This allows for the development of smaller, more powerful, and user-friendly electronic devices.

Cost Efficiency: Copper is already widely used due to its cost-effectiveness. Reinforcing it with graphene, which is becoming increasingly affordable, can provide high thermal conductivity at a lower cost compared to using other metals like silver.

Al heat sink with GO/Cu film for heat removal of LED, (b) Al heat sink with temperature drop for various combinations [184]. Type 1 includes mixed Cu and GO while type 2 has layer by layer structure with intermediate Cu-NP layers.

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