Al-Galiby Qusiy H, Sadeghi Hatef, Algharagholy Laith A, Grace Iain, Lambert Colin
Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK.
Nanoscale. 2016 Jan 28;8(4):2428-33. doi: 10.1039/c5nr06966a.
We investigated the thermoelectric properties of metalloporphyrins connected by thiol anchor groups to gold electrodes. By varying the transition metal-centre over the family Mn, Co, Ni, Cu, Fe, and Zn we are able to tune the molecular energy levels relative to the Fermi energy of the electrodes. The resulting single-molecule room-temperature thermopowers range from almost zero for Co and Cu centres, to +80 μV K(-1) and +230 μV K(-1) for Ni and Zn respectively. In contrast, the thermopowers with Mn(II) or Fe(II) metal centres are negative and lie in the range -280 to -260 μV K(-1). Complexing these with a counter anion to form Fe(III) and Mn(III) changes both the sign and magnitude of their thermopowers to +218 and +95 respectively. The room-temperature power factors of Mn(II), Mn(III), Fe(III), Zn and Fe(II) porphyrins are predicted to be 5.9 × 10(-5) W m(-1) K(-2), 5.4 × 10(-4) W m(-1) K(-2), 9.5 × 10(-4) W m(-1) K(-2), 1.6 × 10(-4) W m(-1) K(-2) and 2.3 × 10(-4) W m(-1) K(-2) respectively, which makes these attractive materials for molecular-scale thermoelectric devices.
我们研究了通过硫醇锚定基团连接到金电极上的金属卟啉的热电性质。通过在Mn、Co、Ni、Cu、Fe和Zn族中改变过渡金属中心，我们能够调节相对于电极费米能的分子能级。由此产生的单分子室温热电势范围从Co和Cu中心的几乎为零，到Ni和Zn中心的分别为+80 μV K⁻¹和+230 μV K⁻¹。相比之下，具有Mn(II)或Fe(II)金属中心的热电势为负，范围在-280至-260 μV K⁻¹之间。将它们与抗衡阴离子络合形成Fe(III)和Mn(III)，会使它们热电势的符号和大小分别变为+218和+95。预计Mn(II)、Mn(III)、Fe(III)、Zn和Fe(II)卟啉的室温功率因数分别为5.9×10⁻⁵ W m⁻¹ K⁻²、5.4×10⁻⁴ W m⁻¹ K⁻²、9.5×10⁻⁴ W m⁻¹ K⁻²、1.6×10⁻⁴ W m⁻¹ K⁻²和2.3×10⁻⁴ W m⁻¹ K⁻²，这使得这些材料对于分子尺度的热电器件具有吸引力。
