Self-assembled molecular monolayers with ultra-low thermal conductance for energy harvesting (QSAMs)

用于能量收集的具有超低热导的自组装单分子层（QSAM）

• 批准号: EP/P027172/1
• 负责人: Christopher Ford
• 金额: $ 45.95万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FP027172%2F1
• 关键词: Self; assembled; molecular; monolayers; ultra

In single molecules, vibrations due to heat (phonons) and electrons both behave quantum-mechanically like waves and so they can exhibit interference, which can be used to manipulate them. It turns out that constructive or destructive interference of phonons and 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 manipulation of room-temperature quantum interference (RTQI) of electrons in single molecules has been realised recently and is a topic of intense competition between research groups in the UK and abroad, simultaneous control of room-temperature phonon interference (RTPI) has not yet been achieved. This project, called QSAMs, aims to deliver the next breakthrough by designing and realising technologically-relevant materials and devices, which exploit both RTPI and RTQI to yield the next generation of thermoelectric materials.Electricity for information technologies currently results in carbon emissions that are comparable to those of the total global aviation industry. QSAMs aims to address the global challenge of reducing these emissions significantly by inventing new materials that efficiently convert the waste heat produced by data centres (or example) into useful electricity. Our target materials are thin films formed from single layers or a few layers of molecules, sandwiched between flat electrodes. Interference will be used to optimise their ability to convert waste heat into electricity and for on-chip cooling. This will be achieved by modifying the vibrational properties of molecules with a high RTQI-driven 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.A crucial property important for heat recovery (in addition to 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 synthesising Christmas-tree-like molecules (connected to the electrodes at top and bottom), in which the trunk of the molecule is connected to branches coming out of the sides, which oscillate in such a way as to cancel out the phonon waves flowing along the trunk. Phonon transport can be further reduced by selecting slippery anchor groups for binding the molecules to the electrodes, in order to scatter phonons at the contacts between the molecules and electrodes. The technical challenges that this proposal addresses are three-fold. The first is to identify theoretically families of molecules that will have the propensity for large RTQI and RTPI 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 and optimise their properties in a vast parallel array of molecules, known as a self-assembled monolayer. Understanding the hurdles that need to be overcome to realise simultaneously RTPI and RTQI in such macroscopic ultra-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 of on-chip cooling and energy-efficient heat recovery.

在单分子中，由于热(声子)和电子的振动都表现出量子力学的行为，就像波一样，所以它们可以表现出干涉，可以用来操纵它们。事实证明，通过在分子中添加不同的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声子和电子的相长或破坏性干扰。尽管操纵单分子中电子的室温量子干涉(RTQI)是最近实现的，也是英国和国外研究小组激烈竞争的主题，但尚未实现对室温声子干涉(RTPI)的同时控制。这个名为QSAMS的项目旨在通过设计和实现与技术相关的材料和设备来实现下一项突破，这些材料和设备利用RTPI和RTQI来生产下一代热电材料。目前，信息技术的电性导致的碳排放相当于全球航空业的总排放量。QSAMS旨在通过发明新材料，有效地将数据中心(或例如)产生的废热转化为有用的电力，来应对大幅减少这些排放的全球挑战。我们的目标材料是夹在平板电极之间的单层或几层分子形成的薄膜。干扰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。这将通过使用高RTQI驱动的塞贝克系数来改变分子的振动特性来实现，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，密切相关的珀尔蒂埃系数决定了可以产生的冷却效应的大小。热回收的一个重要属性(除了电导和塞贝克系数之外)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，可以通过合成圣诞树状的分子(连接到顶部和底部的电极)来设计热导，其中分子的主干连接到从两侧伸出的分支，分支以一种抵消沿主干流动的声子波的方式振荡。通过选择光滑的锚基将分子结合到电极上，以便在分子和电极之间的接触处散射声子，可以进一步减少声子的传输。这项提议解决的技术挑战有三个方面。第一个是从理论上确定具有较大RTQI和RTPI效应倾向的分子家族，并预测哪些原子基团和哪些锚基将优化它们的性质。第二个是合成这些分子，第三个是在一个巨大的平行分子阵列中测量和优化它们的性质，这被称为自组装单分子膜。了解在这种宏观的超薄膜分子阵列中同时实现RTPI和RTQI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。

项目成果

Nanoscale Thermal Transport in 2D Nanostructures from Cryogenic to Room Temperature

• DOI: 10.1002/aelm.201900331
• 发表时间: 2019-08
• 期刊: Advanced Electronic Materials
• 影响因子: 6.2
• 作者: C. Evangeli;J. Spièce;S. Sangtarash;A. Molina‐Mendoza;M. Mucientes;T. Mueller;C. Lambert;H. Sadeghi;O. Kolosov

Tuning the thermoelectrical properties of anthracene-based self-assembled monolayers.

• DOI: 10.1039/d0sc02193h
• 发表时间: 2020-07-14
• 期刊: Chemical science
• 影响因子: 8.4
• 作者: Ismael A;Wang X;Bennett TLR;Wilkinson LA;Robinson BJ;Long NJ;Cohen LF;Lambert CJ
• 通讯作者: Lambert CJ

Optimised power harvesting by controlling the pressure applied to molecular junctions.

通过控制施加到分子连接的压力来优化功率收获。

• DOI: 10.1039/d1sc00672j
• 发表时间: 2021-03-04
• 期刊: Chemical science
• 影响因子: 8.4
• 作者: Wang X;Ismael A;Almutlg A;Alshammari M;Al-Jobory A;Alshehab A;Bennett TLR;Wilkinson LA;Cohen LF;Long NJ;Robinson BJ;Lambert C
• 通讯作者: Lambert C

Electrostatic Fermi level tuning in large-scale self-assembled monolayers of oligo(phenylene-ethynylene) derivatives.

低聚（亚苯基-乙炔基）衍生物大规模自组装单层的静电费米能级调谐。

• DOI: 10.1039/d2nh00241h
• 发表时间: 2022
• 期刊: Nanoscale horizons
• 影响因子: 9.7
• 作者: Wang X

Molecular-scale thermoelectricity: as simple as 'ABC'.

• DOI: 10.1039/d0na00772b
• 发表时间: 2020-11-11
• 期刊: Nanoscale advances
• 影响因子: 4.7