KINGSTON, R.I. – Aug. 28, 2024 – The Office of Naval Research has awarded a three-year, $418,300 grant to University of Rhode Island mechanical engineering assistant professor Ashutosh Giri for his project titled “Leveraging Novel Nanothermometries and First-principles Based Computational Frameworks to Uncover Disruptive EnergyTransfer Mechanisms in Nanostructures.”

The increase in nanotechnology over the last two decades has created new challenges within the field of heat transfer. Electronics are increasingly smaller and easier to utilize, but ensuring they perform efficiently and safely at that scale is vital. For example, cell phones need to be able to function without overheating and burning users. Tablets need to be able to perform the same as a larger processor without frying the components.

The project will lay the foundational groundwork for a basic understanding of microscopic energy carrier dynamics and go beyond the conventional approach of studying the energy carrier “scattering” picture in nanoscale energy transport.

Big ideas in thin films

Energy carriers are what transport heat and electrical charges in materials. With regards to electronics, materials are shrinking to a nanoscale level with thin films. Nano-thin film thickness is down to tens of nanometers. To put that into perspective, nano-thin film is about 10,000th of a single strand of hair. That’s why phones are small enough to fit in pockets, yet capable of performing calculations that were only feasible with supercomputers just several decades ago. Other mainstream applications include the fundamental understanding of how optical coatings, photovoltaic solar cells, and thin film batteries work.

To visualize how energy moves at those length scales requires specialized equipment and methods. “What I am trying to facilitate is a better understanding of how we can control heat transfer in nanomaterials,” said Giri. Thermal management would not be possible without the comprehensive understanding of the microscopic energy conversion and relaxation processes in nanostructured materials, which is the focus of this proposed project.

The ability to directly image these processes with unprecedented spatial resolutions and comprehensively understand how material interfaces influence these fundamental scattering processes will lead to new directions for improving thermal solutions for the Navy’s electronic technologies.

The methods will involve theoretical advancements based on atomic-level calculations that are supported through complementary experimental studies. Prior computational and experimental tools his lab has been pioneering through previous grants will provide the necessary platform for more advanced techniques.

Specialized equipment

Giri’s Energy Transport and Ultrafast Spectroscopy Lab has unique setups that utilize specialized laser-based techniques. For example, thanks to a Champlin Foundation grant-funded Steady-State Thermo-Reflectance in fiber (SSTR-F) instrument from Laser Thermal, the equipment can be used to measure the thermal conductivity or boundary conductance of thin films and coatings ranging from a few nanometers up to tens of microns. The cutting-edge technology increases the capabilities of the lab to advance experimental and computational tools as part of the project and enable revolutionary new discoveries in the physics of heat transfer.

This will eventually help lead the introduction of functional nanomaterials into the Navy’s future microelectronic systems, as well as the construction of the Navy’s all-electric ship. The military uses high-powered electronics with wide-band gap semiconductors. These materials often limit or intensify heat transfer, and studying their efficiency can improve interfacial thermal conductance in reflective fiber systems.

Giri is recognized as a leading expert in the field, most recently earning the Bergles-Rohsenow Young Investigator Award in 2022, as well as the Office of Naval Research’s Young Investigator Award in 2021.