Controlling structural complexity and dynamics in dicyanometallates

控制二氰基金属酸盐的结构复杂性和动力学

• 批准号: 2580987
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2580987
• 关键词: Controlling; structural; complexity; dynamics; dicyanometallates

Thermoelectric materials transform heat into electricity directly. These materials could revolutionise energy efficiency and solve problems associated with the world's growing energy consumption. Their reliability, scalability and long lifespan offer huge potential. It is their low efficiency that has prevented their widespread use. A good thermoelectric material conducts electricity well but heat poorly. Unfortunately, this combination of properties is rare.This research aims to further design of thermoelectrics by probing ways of reducing thermal (or heat) conductivity whilst not affecting other properties of the material. This research is therefore concerned with altering the atomic vibrations of a material. Atoms in solids are constantly vibrating. These vibrations are concerted between atoms. Scientists can calculate the energy of the vibration and the associated movement of atoms. Phonons can be measured using different techniques such as shining infrared light or neutrons on a material. Phonons are critical to understand the thermal properties of a material. Properties such as the expansion of a material as it is heated or its thermal conductivity all rely on phonons. Phonons are the heat carriers for solid materials, and disrupting them leads to lower thermal conductivity.An intuitive way of reducing the thermal conductivity is to introduce defects into the material. Defects are imperfections within the material - this can often be a gap where there should be an atom in the material. Or even an atom of the material in the wrong position. Defects break up the atomic vibrations and can 'scatter' the phonons. Unfortunately, defects also tend to scatter electrons reducing the electrical conductivity of the material. Yet theoretically, one could introduce disorder into a material that can affect the thermal conductivity much more than the electrical conductivity. For this to occur, the disorder must be not be random but correlated. The interplay between disorder and phonons is the subject of this research. This research aims to answer the fundamental question: can one introduce disorder in a systematic manner to affect certain phonons?Dicyanometallates are used to answer this question. These form large crystals and can have their phonons measured easily using neutrons. They also allow a straightforward mechanism for controllably introducing disorder. The hope is that the research proceeds via an iterative process. The effect of disorder on phonon properties will be measured experimentally. These results will then be used to predict the effects of disorder on phonon properties using computational methods. This has the potential to greatly aid thermoelectric design.This research falls in the EPSRC Physical Sciences Research Area. Work will be carried out from the Goodwin and Deringer groups.

热电材料直接将热转化为电。这些材料可以彻底改变能源效率，解决与世界能源消耗增长相关的问题。它们的可靠性、可扩展性和长寿命提供了巨大的潜力。正是它们的低效率阻碍了它们的广泛使用。好的热电材料导电性好，但导热性差。不幸的是，这种性能的组合是罕见的。这项研究的目的是通过探索降低热（或热）传导率的方法，同时不影响材料的其他性能，进一步设计热电。因此，这项研究涉及改变材料的原子振动。固体中的原子不断地振动。这些振动在原子之间协调一致。科学家可以计算出振动的能量和原子的相关运动。声子可以使用不同的技术来测量，例如在材料上照射红外光或中子。声子对于理解材料的热性质至关重要。诸如材料受热时的膨胀或其导热性等性质都依赖于声子。声子是固体材料的热载体，破坏它们会导致热导率降低。降低热导率的一种直观方法是在材料中引入缺陷。缺陷是材料中的缺陷-这通常是材料中应该存在原子的间隙。或者甚至是材料中的一个原子在错误的位置。缺陷会破坏原子的振动，并能“散射”声子。不幸的是，缺陷也倾向于散射电子，从而降低材料的电导率。然而，从理论上讲，人们可以将无序引入到材料中，这种材料对热导率的影响远远大于电导率。要做到这一点，这种紊乱必须不是随机的，而是相关的。无序和声子之间的相互作用是本研究的主题。这项研究的目的是回答一个基本的问题：一个人可以引入无序在一个系统的方式来影响某些声子？双氰尿酸盐用于回答这个问题。它们形成大的晶体，可以很容易地用中子测量它们的声子。它们还允许一种简单的机制来可控地引入紊乱。希望这项研究通过一个迭代过程进行。无序对声子性质的影响将通过实验测量。这些结果将被用来预测的影响，使用计算方法的声子性质的障碍。这项研究福尔斯属于EPSRC物理科学研究领域。工作将由古德温和德林格小组进行。