Torres Alberto, Pontes Renato B, da Silva Antônio J R, Fazzio Adalberto
Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970, São Paulo, SP, Brazil.
Phys Chem Chem Phys. 2015 Feb 21;17(7):5386-92. doi: 10.1039/c4cp04635h.
We theoretically investigate, as a function of the stretching, the behaviour of the thermoelectric properties - the Seebeck coefficient (S), the electronic heat conductance (κel) and the figure of merit (ZT) - of a molecule-based junction composed of a benzene-1,4-dithiolate molecule (BDT) coupled to Au(111) surfaces at room temperature. We show that the thermoelectric properties of a single molecule junction can be tuned by mechanic stretching. The Seebeck coefficient is positive, indicating that it is dominated by the HOMO. Furthermore, it increases as the HOMO level, which is associated to the sulphur atom, tends towards energies close to the Fermi energy. By modelling the transmission coefficient of the system as a single Lorentzian peak, we propose a scheme to obtain the maximum ZT of any molecular junction.
我们从理论上研究了在室温下，由苯 - 1,4 - 二硫醇盐分子（BDT）与Au(111)表面耦合组成的分子结的热电性质——塞贝克系数（S）、电子热导率（κel）和优值（ZT）——随拉伸的变化情况。我们表明，单分子结的热电性质可以通过机械拉伸进行调节。塞贝克系数为正，表明它由最高占据分子轨道（HOMO）主导。此外，随着与硫原子相关的HOMO能级趋向于接近费米能量的能量，塞贝克系数会增大。通过将系统的传输系数建模为单个洛伦兹峰，我们提出了一种获得任何分子结最大ZT的方案。
