How a Sandwich is Transforming Electronics

As devices get smaller and more powerful, the risk of overheating and burning out increases substantially. Despite advancements in cooling solutions, the interface between an electronic chip and its cooling system has remained a barrier for thermal transport due to the materials’ intrinsic roughness.

Sheng Shen , a professor of mechanical engineering at Carnegie Mellon University, has fabricated a flexible, powerful and highly reliable material to efficiently fill the gap.

"At first glance, our solution looks like any ordinary copper film, but under a microscope the novelty of our material becomes clear," explained Lin Jing, a Ph.D. candidate in the Department of Mechanical Engineering.

The material, composed of two thin copper films with a graphene-coated copper nanowire array sandwiched between them, is extremely user-friendly.

"Other nanowires need to be in situ grown where the heat is designed to be dissipated, so that their application threshold and cost is high," said Rui Cheng, postdoctoral researcher in Shen’s lab. "Our film isn’t dependent on any substrate. It is a free-standing film that can be cut to any size or shape to fill the gap between various electrical components."

The "sandwich" builds out of Shen’s " supersolder ," a thermal interface material (TIM) that can be used similarly as conventional solders, but with twice the thermal conductance of current state-of-the-art TIMs.

"At first glance, our solution looks like any ordinary copper film, but under a microscope the novelty of our material becomes clear." - Lin Jing

By coating the "supersolder" in graphene, Shen’s team enhanced its thermal transport capabilities and prevented the risk of oxidation, ensuring a longer service life. The "sandwich," compared to the thermal pastes/adhesives currently on the market, can reduce thermal resistance by more than 90% when considering the same thickness.

Thanks to its ultrahigh mechanical flexibility, the "sandwich" can enable a wide range of applications in flexible electronics and microelectronics, including flexible LEDs and lasers for lighting and display, wearable sensors for communication, implantable electronics for monitoring health and imaging, and soft robotics.

Moving forward, Shen’s team will explore ways to scale the material at an industrial level and lower its cost, while continuing to seek improvements.

"We are very excited about this material’s potential," Shen shared. "We believe that a wide variety of electronic systems can benefit from it by allowing them to operate at a lower temperature with higher performance."

This research first published in ACS Nano and is a collaborative effort with Tzahi Cohen-Karni , a professor of biomedical engineering and materials science and engineering , and Xu Zhang , a professor of electrical and computer engineering , both of Carnegie Mellon University.

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