Thermoelectric Properties of Zinc Etioporphyrin I Single-Molecule Junctions
Yen-Chun Tseng1*, Ke-Chuan Weng1, Chao-Cheng Kaun1,2
1Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
2Department of Physics, National Tsing-Hua University, Hsinchu, Taiwan
* Presenter:Yen-Chun Tseng,
A Zn(II) Etioporphyrin I (ZnEtioI) molecule absorbed on a NiAl surface has two different configurations, leading to two step-like current-voltage (I-V) characterisitcs in such molecular junctions which consist of scanning-tunneling-microscopic (STM) tip/vacuum/ZnEtioI molecule/metallic surface [1,2]. Whereas the reversible conformations of this molecule may provide novel thermoelectric features, however it is relatively unexplored to date. In this work, we employ first-principles calculations [3] based on density functional theory (DFT) and non-equilibrium Green’s function (NEGF) formolism to study the transmission spectra, I-V characterisitics, and thermoelectric properties of ZnEtioI single-molecule junctions. Our calculated I-V curves of the junctions agree with experimental data [2]. The influences of STM-tip height on transmission coefficient are discussed. The junction thermoelectric properties, such as conductance, Seebeck coefficient, Lorenz number and figure of merit, governed by the ZnEtioI molecule, are further predicted.

Keywords: thermoelectric, single-molecule junction, ZnEtioI molecule