Jun Liu
Assistant Professor, Dept of Mechanical & Aerospace Engineering
NC State University

Understanding Thermal Transport in Organic and Hybrid Organic-Inorganic Materials for Thermal Management and Energy Conversion

Location: EB1 Room 1011

Friday, September 25th 2015 - 11:00 am

Thermal transport at micro/ nano-scale plays an important role in many applications such as thermoelectric energy conversion and thermal management of microelectronic devices. In recent years, materials with micro/nano-scale features have opened new possibilities for a variety of novel applications with engineered thermal properties. Compared with pure inorganic materials, nanostructured organic materials or hybrid organic-inorganic materials have received much less attention. These materials have significant application advantages, such as being easy to process, light-weight, low-cost, and flexible. Extreme thermal conductivity and fundamental new physics of thermal transport might exist in hybrid organic-inorganic materials. In this talk, I will present my efforts to understand the thermal transport in organic and hybrid organic-inorganic materials by simulation and characterization. First, I will describe the atomistic simulation work on the effect of the chain parameters of polymers, such as chain orientation, backbone flexibility, monomer type, and molecular weight, on the thermal transport in polymers, which serves as a design guide for the materials explored in the rest of the talk. Second, I will show the measurements on the organic thin films and hybrid organic-inorganic thin films designed with different features of these chain parameters by ultrafast-laser based thermometry. I will demonstrate how the thermal conductivity measurement data on these materials can help understand the thermal transport mechanism and also material growth and structure. These understandings can be applied in fields like organic thermoelectrics, microelectronics, battery, and solar cell. An example is that a layered-structured conducting hybrid organic-inorganic thin film with ultralow thermal conductivity is promising for thermoelectric energy conversion. Third, I investigated thermal transport in intercalated transition metal dichalcogenide. As a more systematic study of layered-structured materials, this fundamental understanding of thermal transport physics can shed some lights on the further development of thermal management and energy conversion materials with semiconducting materials and hybrid organic-inorganic materials. A better understanding of thermal transport in organic and hybrid organic-inorganic materials for thermal management and energy conversion is achieved by those simulation and characterization efforts.

Bio: Dr. Jun Liu is an assistant professor in Department of Mechanical and Aerospace Engineering at NC State. Prior to that, he was a postdoctoral research associate in Materials Science and Engineering Department at University of Illinois at Urbana-Champaign. He received his B.E. in thermal engineering from Huazhong University of Science and Technology (Wuhan, China) in 2008 and Ph. D. in Mechanical Engineering from University of Colorado at Boulder in 2013. He was honored Outstanding Dissertation Award by College of Engineering at CU-Boulder in 2013. His research interests include atomistic simulation and ultrafast-laser characterization of thermal transport, thermal energy conversion and storage, thermal management of microelectronics, and nanoscale thermal transport phenomena in advanced materials.

North Carolina State University