Ismael Ali K, Grace Iain, Lambert Colin J
Department of Physics, Lancaster University, Lancaster, UK.
Nanoscale. 2015 Nov 7;7(41):17338-42. doi: 10.1039/c5nr04907e.
We investigate strategies for increasing the thermopower of crown-ether-bridged anthraquinones. The novel design feature of these molecules is the presence of either () crown-ether or () diaza-crown-ether bridges attached to the side of the current-carrying anthraquinone wire. The crown-ether side groups selectively bind alkali-metal cations and when combined with TCNE or TTF dopants, provide a large phase-space for optimising thermoelectric properties. We find that the optimum combination of cations and dopants depends on the temperature range of interest. The thermopowers of both and are negative and at room temperature are optimised by binding with TTF alone, achieving thermpowers of -600 μV K(-1) and -285 μV K(-1) respectively. At much lower temperatures, which are relevant to cascade coolers, we find that for , a combination of TTF and Na(+) yields a maximum thermopower of -710 μV K(-1) at 70 K, whereas a combination of TTF and Li(+) yields a maximum thermopower of -600 μV K(-1) at 90 K. For , we find that TTF doping yields a maximum thermopower of -800 μV K(-1) at 90 K, whereas at 50 K, the largest thermopower (of -600 μV K(-1)) is obtain by a combination TTF and K(+) doping. At room temperature, we obtain power factors of 73 μW m(-1) K(-2) for (in combination with TTF and Na(+)) and 90 μW m(-1) K(-2) for (with TTF). These are higher or comparable with reported power factors of other organic materials.
我们研究了提高冠醚桥连蒽醌热电势的策略。这些分子的新颖设计特点是在载流蒽醌线的一侧连接有（）冠醚或（）二氮杂冠醚桥。冠醚侧基选择性地结合碱金属阳离子，当与四氰基乙烯（TCNE）或四硫富瓦烯（TTF）掺杂剂结合时，为优化热电性能提供了很大的相空间。我们发现阳离子和掺杂剂的最佳组合取决于感兴趣的温度范围。和的热电势均为负，在室温下仅与TTF结合时热电势得到优化，分别达到-600 μV K⁻¹和-285 μV K⁻¹。在与级联冷却器相关的更低温度下，我们发现对于，TTF和Na⁺的组合在70 K时产生最大热电势-710 μV K⁻¹，而TTF和Li⁺的组合在90 K时产生最大热电势-600 μV K⁻¹。对于，我们发现TTF掺杂在90 K时产生最大热电势-800 μV K⁻¹，而在50 K时，通过TTF和K⁺掺杂的组合获得最大热电势（-600 μV K⁻¹）。在室温下，我们得到（与TTF和Na⁺组合）的功率因子为73 μW m⁻¹ K⁻²，（与TTF组合）的功率因子为90 μW m⁻¹ K⁻²。这些高于或与其他有机材料报道的功率因子相当。
