Excellent thermoelectric performance in weak-coupling molecular junctions with electrode doping and electrochemical gating  

作　　者：Dan Wu Xuan-Hao Cao Pin-Zhen Jia Yu-Jia Zeng Ye-Xin Feng Li-Ming Tang Wu-Xing Zhou Ke-Qiu Chen 

机构地区：[1]Deparment of Applied Physics,School of Physics and Electronics,Hunan University.Changsha 410082.China [2]School of Materials Science and Engineering,Hunan University of Science and Technology&Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion,XiangTan 411201,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2020年第7期78-88,共11页中国科学：物理学、力学、天文学（英文版）

基　　金：the National Key Research and Development Program of China(Grant No.2017YFB0701602);the National Natural Science Foundation of China(Grant No.11674092)。

摘　　要：Excellent thermoelectric performance in molecular junctions requires a high power factor, a low thermal conductance, and a maximum figure of merit(ZT) near the Fermi level. In the present work, we used density functional theory in combination with a nonequilibrium Green’s function to investigate the thermoelectric performance of carbon chain-graphene junctions with both strong-coupling and weak-coupling contact between the electrodes and the molecules. The results revealed that a room temperature ZT of 4 could be obtained for the weak-coupling molecular junction, approximately one order of magnitude higher than that reached by the strong-coupling junction. The reason for this is that strong interfacial scattering suppresses most of the phonon modes in weak-coupling systems, resulting in ultralow phonon thermal conductance. The influence of electrode width,electrode doping, and electrochemical gating on the thermoelectric performance of the weak-coupling system was also investigated, and the results revealed that an excellent thermoelectric performance can be obtained near the Fermi level.

关 键 词：THERMOELECTRIC molecular junctions WEAK-COUPLING electrochemical gating density functional theory 

分 类 号：O646.5[理学—物理化学]