| dc.description.abstract | As electronic chip equipment becomes more and more powerful, the power it consumes continues to rise, leading to an increase in the amount of heat energy dissipation. Heat dissipation has emerged as a significant area of research in electronic equipment to address the cooling requirements. Conventional heat dissipation materials composed of silicon can no longer achieve the desired heat dissipation efficiency for high-power computing chips. By contrast, nanocarbon materials, such as carbon nanotubes (CNTs) and graphene platelets (GnPs), inherently possess exceptionally high electrical conductivity (≧ 104 S/cm) and thermal conductivity (≈ 3500 W/mK). Their high electrical conductivity, combined with large surface-to-volume ratio, provides an application for an assembly of the nanomaterials as electrodes in supercapacitors and fuel cells. In addition, following the miniaturization of microelectronics and advances in portable devices, their lightweight property makes them appealing with the rapid increase in demand for compact and high energy density batteries.
Buckypapers are a form of carbon-based thin film, known for their unique integration of single-wall or multi-wall carbon nanotubes through the intermolecular Van der Waals force. This process results in a paper-like structure. Similarly, graphene papers are another type of carbonaceous material that possess a high surface area, strong chemical stability, and impressive thermal conductivity. Given the exceptional thermal conductivity of these carbonaceous materials, we anticipate that papers produced from carbon nanotubes and graphene will have superior heat dissipation capabilities.
The objective of this work is to use filtering technology for the production of CNT/GnP composite paper, and to conduct a comparative analysis with printed buckypaper. Attachments are not necessary for them; nevertheless, they possess flexibility and the ability to adapt to many situations. It is important to note that no adhesives are used in the production process. Adhesives often improve the adherence of carbon nanotubes and enhance their flexibility. Nevertheless, due to the insulating nature of most adhesives, they create a barrier between the two substances, hindering the transfer of heat and hence exhibiting better thermal conductivity in comparison to current thermal pads. These novel binder-free composites provide exceptional heat conductivity and provide quick and adaptable interface filling. Similarly, the electrical conductivity of the CNTs and graphene, can be largely preserved, providing that the contact resistance can be minimized. Thus, in this study, the electrical conductivity of the CNT/GnP films, generated by filtration, has been evaluated by four-probe point testing. It has been shown that the electrical conductivity of the fabricated CNT/GnP films improved after rolling as compared to its as-fabricated state. Out of all the samples, the graphene sheet with the highest conductivity had a measured value of 149.81 S/cm. Furthermore, the observation of the thermal conductivity value was conducted in addition to the measurement of electrical conductivity. The measurements of printed carbon nanotube/graphene composite sheets with varying fractions were measured at room temperature using the Hot Disk transient plane heat source technique.
At a ratio of 67:33 between CNT and graphene, the thermal conductivity reached a peak value of 116.73 W/mK. These values are comparable to those of nickel foil and three times greater than those of commercial thermal pads. Furthermore, the experiment was conducted on the surface of the CPU of a computer, and the temperature was recorded under maximum CPU usage. The temperature decreased from 62℃ to 49℃ than compared to the CPU temperature without buckypaper. This work displays the exceptional electrical and thermal conductivity qualities of these novel carbonaceous composites, establishing them as a groundbreaking choice for both electrical applications and thermal management. | en_US |