Research in Ultra-High Thermal Conductivity

Dr. Jivtesh Garg and his graduate students are exploring a new class of ultra-hard boron-carbide materials such as BC2N and BC5 for ultra-high thermal conductivity values. Their goal is to achieve thermal conductivity values higher than diamond and graphene (> 5000 W/mK).

They are using quantum-mechanical calculations based on density-functional theory to predict thermal transport properties. Simultaneously the group is using laser-based frequency-domain thermoreflectance measurements (FDTR) to experimentally measure these high thermal conductivity values. Ph.D. students Rajmohan Muthaiah, Avinash Nayal, and Roshan Annam are conducting this research.

The group has also developed advanced functionalization schemes to more efficiently couple graphene with polymers for thermal transport applications. Graphene is a wonder material with extraordinary thermal, mechanical, and electrical properties. By efficiently coupling graphene with polymer, a large enhancement in properties can be achieved. Initial experimental results suggest dramatic improvement in the thermal conductivity of polymers such as polyetherimide. Developed functionalization schemes are being applied to a wide range of polymers. Ph.D. students Fatema Tarannum and Swapneel Danayat are involved in this research.

They are further exploring non-equilibrium phonon effects for the design of high-efficiency hot carrier solar cells and thermoelectric materials. Electrons in solar cells thermalize through interactions with lattice vibrations (phonons). By engineering non-equilibrium phonon effects to generate hot phonons, the thermalization of electrons can be inhibited, thereby enhancing solar cell efficiency. Non-equilibrium phonon effects also enhance the efficiency of thermoelectrics by mitigating heat loss through lattice vibrations.  Fundamental first-principles techniques coupled with Monte-Carlo simulations are being used to study non-equilibrium phonon effects.

Through advanced simulations and state-of-the-art experimental measurements, the group aims to develop the next generation of advanced composite materials for thermal management and energy conversion applications and is a world leader in thermal management technologies.