CAREER: Phononic Properties of Colloidal Nanocrystal Superlattices

职业：胶体纳米晶体超晶格的声子特性

• 批准号: 1654337
• 负责人: Robert Wang
• 金额: $ 56.25万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-03-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1654337&HistoricalAwards=false
• 关键词: CAREER; Phononic; Properties; Colloidal; Nanocrystal

Non-Technical AbstractElectricity, light, sound, and heat are common phenomenon encountered in everyday life. Materials that enable advanced control over the transmission of electricity and light are known as electronic and photonic materials, respectively. These materials have made possible numerous modern technologies such as laptops, cellular phones, fiber optics, lasers, and microscopes. In contrast, technological control over sound and heat has lagged far behind that of light and electricity. This project focuses on the creation of phononic materials that could enable advanced control over the transmission of sound and heat. These phononic materials will consist of organized nanoparticle-molecule assemblies that possess vibrational characteristics that do not arise in naturally occurring materials. These assemblies will then be used to create filters, mirrors, and one-way valves that manipulate the transmission of sound and heat. This project is also integrated with a variety of educational activities. It will engage K-12 students and help train future STEM educators through the Science is Fun program at the LeRoy Eyring Center for Solid State Science. In addition, a laboratory module on phononic crystals will be developed for undergraduate students. Research results will be incorporated into a graduate student course on nanoscale heat transfer. Technical AbstractPhononic crystals are artificially structured materials with periodic variations in acoustic impedance (i.e., alternating hard and soft materials). This periodicity results in a phononic band gap that enables the creation of many phononic devices such as phonon filters, waveguides, diodes, and mirrors. The objectives of this project are to: (1) Demonstrate the potential of nanocrystal superlattices for phononic applications, (2) Achieve phononic band gaps in the 100 GHz regime for 3-dimensional phononic crystals, (3) Control transmission and reflection of heat transporting phonons in nanocrystal superlattices, and (4) Create high frequency phononic devices such as phonon filters, mirrors, and diodes. The phononic band gap center and phononic band gap width will be tuned via nanocrystal size and composition as well as ligand composition. DNA will also be used to direct nanocrystal assembly and enable diverse structural possibilities. To ensure mechanical, chemical, and thermal stability of the superlattices, the DNA linkers will be converted into an inorganic matrix via sol-gel chemistries. Phonon transmission and reflection will be experimentally studied using phonon spectroscopy, which uses monochromatic phonon generators and detectors to directly measure frequency-resolved phonon transport. These experiments will be complemented with computational modeling that calculates the phononic band diagram and simulates phonon transport using plane wave expansion methods and finite-difference time-domain methods, respectively. The nanocrystal superlattices will also be integrated with substrates by growing them from templates fabricated via electron beam lithography; thereby opening the door for future chip-integrated applications.

非技术摘要电、光、声、热是日常生活中常见的现象。能够对电和光传输进行高级控制的材料分别称为电子材料和光子材料。这些材料使许多现代技术成为可能，例如笔记本电脑、手机、光纤、激光和显微镜。相比之下，对声音和热的技术控制远远落后于光和电。该项目的重点是创建声子材料，可以对声音和热量的传输进行高级控制。这些声子材料将由有组织的纳米粒子-分子组件组成，这些组件具有天然材料中不存在的振动特性。然后，这些组件将用于创建过滤器、镜子和单向阀，以控制声音和热量的传输。该项目还与各种教育活动相结合。它将吸引 K-12 学生，并通过 LeRoy Eyring 固态科学中心的 Science is Fun 计划帮助培训未来的 STEM 教育工作者。此外，还将为本科生开发声子晶体实验室模块。研究成果将被纳入纳米级传热研究生课程中。技术摘要声子晶体是声阻抗周期性变化的人工结构材料（即硬质和软质材料交替）。这种周期性导致声子带隙，从而能够创建许多声子器件，例如声子滤波器、波导、二极管和镜子。该项目的目标是：(1) 展示纳米晶体超晶格在声子应用中的潜力，(2) 实现 3 维声子晶体在 100 GHz 范围内的声子带隙，(3) 控制纳米晶体超晶格中传热声子的传输和反射，以及 (4) 创建高频声子器件，如声子滤波器、镜子和二极管。声子带隙中心和声子带隙宽度将通过纳米晶体尺寸和成分以及配体成分来调节。 DNA 还将用于指导纳米晶体组装并实现多种结构可能性。为了确保超晶格的机械、化学和热稳定性，DNA 连接体将通过溶胶-凝胶化学转化为无机基质。将使用声子光谱学对声子传输和反射进行实验研究，声子光谱学使用单色声子发生器和探测器来直接测量频率分辨声子传输。这些实验将得到计算模型的补充，计算模型分别使用平面波展开方法和有限差分时域方法计算声子能带图并模拟声子输运。纳米晶体超晶格还将通过电子束光刻制造的模板生长来与基底集成；从而为未来的芯片集成应用打开了大门。

项目成果

A machine learning based approach for phononic crystal property discovery

• DOI: 10.1063/5.0006153
• 发表时间: 2020-07
• 期刊: Journal of Applied Physics
• 影响因子: 3.2
• 作者: Seid M. Sadat;Robert Y. Wang