CAREER: Manipulating Barocaloric Effects in Two-Dimensional Perovskites

职业：操纵二维钙钛矿中的气压效应

• 批准号: 2238113
• 负责人: Jarad Mason
• 金额: $ 82.3万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2028-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2238113&HistoricalAwards=false
• 关键词: CAREER; Manipulating; Barocaloric; Effects; Two

Non-technical summary:Phase transitions (i.e., going from a solid to a liquid) enable large changes in the properties of a material to be triggered by a small change in an external stimulus, and thus provide a versatile mechanism for the design of advanced, responsive materials. Despite the tremendous importance of phase transitions, creating materials that transition between two phases—each with a particular set of desired properties—is a challenge. Through this award, funded by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF, Prof. Jarad Mason aims to advance the basic science of phase transitions through a fundamental study of the structural and chemical factors that control transitions between ordered and disordered states within hybrid (i.e., organic and inorganic) materials, as well as how these transitions are affected by the application of pressure. Such phase transitions offer exciting opportunities for addressing many critical societal challenges, including how to reversibly store high densities of thermal energy and how to develop more sustainable cooling technologies that do not rely on environmentally harmful volatile refrigerants. In addition, this project aims to broaden participation in scientific research and to facilitate public engagement in basic science and technological innovations through curriculum development, mentorship of high school students, and outreach to K-12 students, high school teachers, and the general public. Technical summary:Barocaloric effects are thermal changes in a material that result from the application or removal of hydrostatic pressure. These effects, which can be used to drive solid-state cooling, heat pump, and thermal energy storage cycles, are strongest when a material experiences a large change in volume and entropy over a narrow temperature range, such as during a sharp order–disorder phase transition. Although critical to realizing the full potential of barocaloric effects, it remains difficult to predictably manipulate order-disorder phase transitions in the solid state, and much remains to be understood about the specific structural and chemical factors that contribute to barocaloric effects at a molecular level. With this CAREER project, Prof. Mason will address these challenges through a systematic investigation of barocaloric effects associated with chain-melting phase transitions in two-dimensional hybrid perovskites. Owing to their synthetic tunability, two-dimensional perovskites serve as a powerful platform to establish fundamental structure–property relationships that advance the development of barocaloric materials. Specifically, the principal hypothesis guiding this research is that the organic bilayers and inorganic sheets in two-dimensional metal–halide perovskites can be synthetically tuned to control the entropy changes, enthalpy changes, volume changes, hysteresis, and kinetics of chain-melting transitions and, consequently, their barocaloric properties. In this project, new materials synthesis and in-depth characterization by X-ray diffraction, calorimetry, neutron scattering, and infrared and solid-state NMR spectroscopies are utilized to investigate the thermodynamics, kinetics, and reversibility of order–disorder transitions in two-dimensional perovskites.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要：相变（即，从固体到液体）使材料的性质发生很大变化，可以由外部刺激的微小变化触发，因此为高级响应材料设计提供了一种多功能机制。尽管相变的重要性非常重要，但创造了在两个阶段之间过渡的材料，即具有特定的所需属性，这是一个挑战。通过该奖项，由NSF材料研究部的固态和材料化学计划资助，贾拉德·梅森教授旨在通过对控制混合动力（即有机和内部材料）内部造成的结构和无序状态之间的结构和化学因素来推进相过渡的基础科学，这些因素是有机和无机材料以及这些过渡的方式。这种相转换为解决许多关键的社会挑战提供了令人兴奋的机会，包括如何可逆地存储高密度的热能，以及如何开发不依赖环境有害的挥发性制冷剂的更可持续的冷却技术。此外，该项目旨在扩大科学研究的参与，并通过课程发展，高中生的指导以及向K-12学生，高中老师和普通公众推广，促进公众参与基础科学和技术创新。技术摘要：漏？效应是由于施加或去除静水压力而导致的材料中的热变化。当材料经历在狭窄的温度范围内的体积和熵发生巨大变化时，这些效果可用于推动固态冷却，热泵和热量储能周期，例如在急剧的订单 - 分类阶段发生较大的变化，尽管对于实现压力平衡的全部潜力至关重要，但仍难以预测地，在实现降级的情况下，并且在稳固状态下仍然很难进行构造，并且在构建方面的构建依赖性的构建因素，并且在实现方案阶段，并且在实现阶段的阶段，并且在稳固性的阶段中仍然可以理解，并且可以使许多构建的构造因素构成，并且在实现阶段至关重要，并且可以在较窄的阶段进行实现的构建，并且在实现了较低的阶段，并且在较低的阶段中既可以实现均可效应，并且很难实现构造的质量变化。分子水平的低空平原效应。通过这个职业项目，梅森教授将通过系统地研究与二维混合钙钛矿中的链熔融相变相关的压力效应，以解决这些挑战。由于它们的合成可线性性，二维钙钛矿是建立基本结构与专业关系的强大平台，从而推动了压力性材料的发展。具体而言，指导这项研究的主要假设是，可以合成调整二维金属 - halide钙钛矿中的有机双层和无机板，以控制熵变化，焓变，体积变化，体积变化，障碍物，子宫和动力学的链条过渡和链条质量，因此，其脱发。在这个项目中，利用X射线衍射，量热法，中子散射以及红外和固态的NMR Spectroscopies来研究热力学，动力学，动力学，动力学，动力学和订单的可逆性，在二维perovskites中的阶级和差异的依据。使用基金会的智力优点和更广泛的影响评估标准进行评估。