Quantum-Interference-Enhanced Thermoelectricity (QUIET).

量子干涉是一种机制，它可以通过利用电子既可以被认为是波又是粒子的性质来操纵单个分子的电学性质。事实证明，通过在分子中添加各种原子基团或仔细选择分子与外部电极的连接，可以精确地设计单个有机分子中电子的相长或相消干涉。尽管操纵单分子中量子干涉的梦想已经讨论了很多年，但单分子结中室温干涉效应的实验证据直到最近才有报道。在这些量子干涉演示的基础上，Quiet的目标是通过设计和实现与技术相关的材料和设备来实现下一个突破，这些材料和设备利用室温及更高温度的量子干涉。目前，信息技术产生的废热导致的碳排放相当于全球航空业的总排放量。Quiet旨在通过发明新材料来应对这一全球挑战，这种新材料可以有效地将废热转化为有用的电力。我们的目标材料是夹在平面电极之间的单层或几层分子形成的薄膜。量子干涉将被用来优化他们将余热转化为电能和芯片上冷却的能力。这将通过设计、合成和测量具有高塞贝克系数的分子来实现，塞贝克系数决定了当温差施加到分子或薄膜的两侧时产生的电压。相反，如果在分子上施加电压，密切相关的帕尔蒂埃系数决定了可以产生的冷却效应的大小。结果表明，塞贝克系数与分子中电子的数量成正比，也与电子态密度如何随能量分布成正比。这两个都可以通过量子干涉在某些有机分子家族中进行操纵。热回收的第三个重要性质(前两个是电导和塞贝克系数)是热导，它需要很低。在一种块状材料中，很难同时设计高电导和低热导。然而，对于附着在电极上的单分子或薄分子薄膜，可以通过选择光滑的锚基、将分子结合到电极上以及通过引入软的内部机械自由度来设计热导，从而进一步减少声子的传输。第一个是从理论上确定有可能产生大量子干涉效应的分子家族，并预测哪些原子基团和哪些锚基将优化它们的性质。第二步是合成这些分子，第三步是在单分子水平上测量它们的性质，反馈给理论模型。第四个也是最后一个挑战是，当分子变成一个巨大的平行分子阵列，也就是所谓的自组装分子层时，这些优越的性质是否仍然存在。了解在宏观分子薄膜阵列中实现室温量子干涉效应需要克服的障碍，将有助于确定在现实世界中具有重要社会和经济影响的新型技术的第一步，并解决芯片上冷却和节能热回收的紧迫问题。

Quantum interference is a mechanism which can be used to manipulate the electrical properties of a single molecule by exploiting the property that an electron can be considered to be a wave as well as a particle. It turns out that constructive or destructive interference of electrons within individual organic molecules can be engineered precisely by the addition of various atomic groups to the molecule or by carefully selecting the connection of the molecule to external electrodes. Although the dream of manipulating quantum interference in single molecules has been discussed for many years, experimental evidence of room-temperature interference effects in single-molecule junctions was reported only recently. Building on these demonstrations of quantum interference, QuIET aims to deliver the next breakthrough by designing and realising technologically-relevant materials and devices, which exploit quantum interference at room-temperature and above.Waste heat from information technologies currently results carbon emissions which are comparable to those of the total global aviation industry. QuIET aims to address this global challenge by inventing new materials, which efficiently convert this waste heat into useful electricity. Our target materials are thin films formed from single layers or a few layers of molecules, sandwiched between planar electrodes. Quantum interference will be used to optimise their ability to convert waste heat into electricity and for on-chip cooling. This will be achieved by designing, synthesising and measuring molecules with a high Seebeck coefficient, which determines the voltage generated when a temperature difference is applied to the two sides of a molecule or a thin film. Conversely, if a voltage is applied across a molecule, the closely-related Peltier coefficient determines the magnitude of the cooling effect that can be created.It turns out that the Seebeck coefficient is proportional to the number of electrons within the molecule and also how the density of electronic states is distributed with energy. Both of these can be manipulated in certain families of organic molecules using quantum interference. A third property important for heat recovery (the first two being the electrical conductance and the Seebeck coefficient) is the thermal conductance, which needs to be low. Within a bulk material it is difficult to engineer simultaneously high electrical conductance and low thermal conductance. However for single molecules or thin molecular films attached to electrodes, the thermal conductance can be engineered by selecting slippery anchor groups, for binding the molecules to the electrodes and by introducing soft internal mechanical degrees of freedom, which further reduce phonon transport.The technical challenges that this proposal addresses are four-fold. The first is to identify theoretically families of molecules that will have the propensity for large quantum interference effects, and to predict which atomic groups and which anchor groups will optimise their properties. The second is to synthesise these molecules and the third is to measure their properties at the single molecular level to feed back to the theoretic models. The fourth and final challenge is to investigate whether these superior properties persist when the molecules are turned into a vast parallel array of molecules, known as a self-assembled molecular layer. Understanding the hurdles that need to be overcome to realise quantum interference effects at room temperature in macroscopic thin-film arrays of molecules, will help identify the first steps to a new type of technology that has important societal and economic impacts in the real world and addresses pressing problems with on-chip cooling and energy-efficient heat recovery.