报告人：Prof. Dongyan Xu  The Chinese University of Hong Kong

邀请人：王洪超

报告时间：2019-12-20 上午 10:30

报告地点：知新楼C座七层会议室

报告内容:

The suspended thermal bridge method is the most commonly used technique to characterize the Seebeck coefficient, electrical conductivity, and thermal conductivity of thermoelectric nanowires/nanoribbons. Recently, we have modified the design of the traditional suspended micro-device by adding two additional probes on each suspended membrane and extended this technique for Hall measurement, which will give semiconducting properties of nanoribbons such as carrier type, concentration, and mobility. In addition, copper atoms can be intercalated into and deintercalated from bismuth selenide nanoribbons by a facile chemical method and their effects on thermoelectric properties are characterized by the suspended thermal bridge method. Interestingly, copper intercalation induces a crossover in thermal conductivity over the measured temperature range. The enhanced thermal conductivity at high temperatures and the suppressed thermal conductivity at low temperatures are due to the competing effects of the enhancement in electronic thermal conductivity and the defect-induced reduction in the lattice thermal conductivity. On the other hand, the Seebeck coefficient measurement reveals that a transition from n-type to p-type occurs after copper intercalation and it can be reversed by copper deintercalation. Our work demonstrates a facile method to tune thermoelectric properties of bismuth selenide nanoribbons and may enable new opportunities for thermoelectric applications.

报告人简介：

Prof. Dongyan Xu is currently an Associate Professor in the Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong. Prof. Xu received her Bachelor, Master, and Ph.D. degrees from Tsinghua University and Vanderbilt University. After that, she worked as a Postdoc in the University of California, Berkeley and Lawrence Berkeley National Laboratory for two years. She joined CUHK in 2010 as an Assistant Professor and was promoted to Associate Professor in 2016. Her current research interests include nanoscale heat transfer, thermoelectric materials and devices, thermal management, and boiling heat transfer.

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