Our mission: 

The non-renewables required for electricity generations, involved transport and manufacturing processes reject large amounts of energy as low-grade waste heat. More precisely, according to the national energy consumption report, more than 60% of the current energy usages are typically rejected as thermal energy, which necessitates the thermal energy engineering without entailed substantial cost.  

In a narrower context, the outperformance of high-end industrial applications can be achieved by the transformation of the energy transfer properties, which are ultimately determined by microscopic transport properties of the energy-carrying quasi-particles such as phonons, electrons, polarons, excitons and polaritons. 

By employing optical spectroscopy and ultrafast electron microscopy, we systematically investigate transport phenomena of microscopic energy (thermal and electronic) carriers, to develop highly efficient novel energy materials and devices. Specifically, we seek to study thermal conduction in inorganic / organic materials, radiative cooling, and ultrafast photocarrier imaging.

Developing thermal conductivity spectroscopy 

We are developing novel thermal conductivity spectroscopy to study energy-carrying quasi-particle transport in emerging materials to to engineer them with unique thermal properties.

Material Engineering for thermal applications

We are engineering materials such as thermally conductive polymers, to potentially challenge traditional materials such as metals for applications including electrical circuits to heat-dissipation in vehicles.

[1] T. Kim, S. X. Drakopoulos, S. Ronca, A. J. Minnich, “Origin of high thermal conductivity in disentangled ultra-high molecular weight polyethylene films: ballistic phonons within enlarged crystals”, Nature Communications, 13(1), 2452, (2022)

[2] T. Kim., J. Moon, A. J. Minnich, "Origin of micron-scale propagation lengths of heat-carrying acoustic excitations in amorphous silicon", Physical Review Materials 5, 065602, (Jun. 2021).

[3] T. Kim, D. Ding, J. -H. Yim, Y. -D. Jho. A. J. Minnich, "Elastic and Thermal Properties of Free-Standing Molybdenum Disulfide Membranes measured using Ultrafast Transient Grating Spectroscopy", APL Materials, 5(086105), (Aug. 2017)

Scanning ultrafast electron microscopy (SUEM)

We are developing novel ultrafast imaging tools to study surface transport phenomena of photoelectrons in materials and devices.

Material Engineering for electronic applications

We are collaborating with leading experts in the synthesis of semiconducting polymer and other emerging materials to engineer them with unique electronic properties for diverse applications including solar cells, photovoltaics, and photo-catalysis.

[1] T. Kim, S. Oh, U. Choudhry, C. Meinhart, M. L. Chabinyc, B. Liao, “Transient strain induced electronic structure modulation in a conducting polymer imaged by scanning ultrafast electron microscopy”, Nano Letters, 21, 9146, (Oct. 2021)

Passive radiative cooling system.

We are working to harvest energy through far-field radiation for applications in radiative cooling.

Manipulating near-field thermal radiation.

We are working to develop a scheme to extract resonant surface energy through the coupling with external work.

[1] Ding, D†., T. Kim†, A. J. Minnich, " Active Thermal Extraction and Temperature Sensing of Near-field Thermal Radiation ", Scientific Reports 6, 32274 (Sep. 2016).