报告人：Prof. Woochul Kim Yonsei University, Korea
邀请人：王洪超
报告时间：2019-12-20 上午 9:30
报告地点：知新楼C座7层会议室
报告内容:
In the first part of the talk, we are going to present our efforts on phonon engineering for thermoelectric application. In particular, we are going to present thermal conductivities (k) and thermoelectric properties (zT) of Na doped PbTe and SnTe. We investigated three different routes of synthesizing 2% Na-doped PbTe and found that its thermoelectric figure of merit, zT, can be enhanced to ~2.0 at 773 K. Our study shows that the size of nano- and microstructures can vary significantly by the choice of synthesis methods, which can explain the variation in zTs and mechanical hardness. In addition, we are going to present our recent work on SnTe exhibiting zT ~ 1.9 at 929 K. The main reason for such reduction was also for the thermal conductivity reduction.
In the second part, we demonstrate that conventional inorganic materials can be used in wearable systems despite their bulky and rigid nature. Here, we present two different device architecture for wearable application, i.e., body heat harvesting and personal refrigeration. In particular, we proposed a bracelet-like modular design of a thermoelectric (TE) module with a heat sink made of rigid inorganic bulk materials for body heat harvesting. When the device is worn on the wrist, it generates an output power of 6.97 μW/cm2 while the subject is walking. For personal refrigeration, we propose a mat-like flexible thermoelectric system (FTES) based on rigid inorganic bulk materials. For refrigeration using portable batteries as power sources, the refrigerated skin temperature was lowered by several degrees which is adequate for humans to perceive coldness, according to theoretical analysis. These show potential for wearable refrigeration and body heat harvesting.
报告人简介：
Prof. Woochul Kim received his Ph.D. at U. C. Berkeley in 2005. He has been in Yonsei University since 2007. He was a consulting professor at LG Innotek. He is the recipient of the Prime Minister’s Award in Nanotechnology Research Innovation in 2017, Young Thermal Engineer Award by KSME in 2013, KSTP TPP Award in 2015 and KSTP Research Excellence Award in 2013 (Korean Society of Thermophysical Properties). His research expertise lies on nanoscale thermal transport. For an application field, he is working on thermoelectric.
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