Collaborative Research: EAGER: Enhancing Pyroelectric Effects in Nanostructured Materials for High-Efficiency Energy Conversion

合作研究：EAGER：增强纳米结构材料的热释电效应以实现高效能量转换

• 批准号: 1549942
• 负责人: Alexander Balandin
• 金额: $ 7.5万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1549942&HistoricalAwards=false
• 关键词: Collaborative; Research; EAGER; Enhancing; Pyroelectric

A large amount of energy is lost as waste heat in many engineering systems such as automobiles and turbomachinery. Significant energy gains may be obtained by efficiently scavenging such waste heat through appropriate energy conversion mechanisms. One particularly promising opportunity lies in the conversion of temperature gradients in time into electricity, referred to as the pyroelectric effect. This project will utilize experiments and theoretical modeling to explore the pyroelectric effect in nanowires, and will build prototype pyroelectric-based energy harvesting microdevices. Research will help understand the nature of pyroelectric effect in nanowires, including the amount of energy that may be realistically harvested from nanowire based devices, performance limits, etc. which will help guide further development of potential energy conversion devices. All three institutions involved in this collaborative research are minority serving institutions located in highly populated Hispanic areas. PIs will leverage this opportunity to excite and recruit minority and women students to the emerging nano/microscale energy harvesting area. The PIs will carry out outreach to local high schools to excite K-12 students about energy harvesting, and encourage them to consider further STEM education and careers.The technical goal of this combined experimental and theoretical-simulation research is to measure and characterize the pyroelectric effect in nanowires (GaN, ZnO, etc.) for developing micro- and nano-scale devices for thermal energy harvesting and sensors applications. Despite its potential to convert waste heat into usable electricity, the pyroelectric effect has been largely unexplored, in particular at the micro/nanoscale. This is partially due to lack of methodologies for characterization of this effect at small scales. Recent theoretical findings suggest a dramatically higher pyroelectric coefficient in nanowires, similar to enhancements observed in thermoelectric and piezoelectric performance of nanowires, albeit this prediction has not been confirmed experimentally. In this effort, a methodology based on microfabricated devices will be developed to quantitatively measure and characterize the pyroelectric properties of individual suspended nanowires. In addition, theoretical models and computational tools will be developed for (i) interpretation and analysis of the experimental pyroelectric data; (ii) prediction of the pyroelectric response of various nanostructured materials (individual nanowires; nanowires arrays); and (iii) optimization of the nanostructure parameters (material composition, size, shape, interface) for enhancing the pyroelectric voltage. The proposed models will include strong non-uniformity of the polarization distribution in nanostructures and possible phonon and electron confinement effects. Based on the learning from experiment and theory, prototype pyroelectric-based energy harvesting microdevices will be built using a single and an array of nanowires. Experimental data on pyroelectric coefficient of nanowires and dependence on nanowire size, temperature, etc. will contribute to the fundamental understanding of this effect. A fundamental understanding of pyroelectric transport in single nanowires may lead to a new paradigm of high efficiency energy conversion devices that take advantage of nanoscale engineering of materials to optimize pyroelectric performance.

在许多工程系统（例如汽车和涡轮机械）中，随着废热的浪费，大量能量会损失。可以通过适当的能量转换机制有效清除此类废热来获得显着的能量增益。一个特别有前途的机会在于，时间段的温度梯度转化为电力，称为pyroelectric效应。该项目将利用实验和理论模型来探索纳米线中的pyroelectric效应，并将建立基于Pyroelectric的原型能量收获微电视。研究将有助于理解纳米线中层状效应的性质，包括从基于纳米线的设备，性能限制等实际收获的能量量，这将有助于指导势能转换设备的进一步开发。参与这项合作研究的所有三个机构都是位于人口稠密的西班牙裔地区的少数民族服务机构。 PI将利用这一机会激发和招募少数民族和女学生到新兴的纳米/微观能量收集区。 The PIs will carry out outreach to local high schools to excite K-12 students about energy harvesting, and encourage them to consider further STEM education and careers.The technical goal of this combined experimental and theoretical-simulation research is to measure and characterize the pyroelectric effect in nanowires (GaN, ZnO, etc.) for developing micro- and nano-scale devices for thermal energy harvesting and sensors applications.尽管具有将废热转换为可用的电力的潜力，但在微观/纳米级，尤其是在很大程度上尚未探索的载火效应。这部分是由于缺乏在小尺度上表征这种效应的方法。最近的理论发现表明，纳米线中的pyroelectric系数较高，类似于在纳米线的热电和压电性能中观察到的增强，尽管尚未在实验中证实这种预测。在这项工作中，将开发基于微型制造设备的方法，以定量测量和表征单个悬浮纳米线的高电特性。此外，将开发理论模型和计算工具，以（i）解释和分析实验性pyroelectric数据； （ii）预测各种纳米结构材料（各个纳米线；纳米线阵列）的层状响应； （iii）优化纳米结构参数（材料组成，大小，形状，界面），以增强层状电压。所提出的模型将包括纳米结构中极化分布的强大不均匀性以及可能的声子和电子限制效应。基于实验和理论的学习，将使用单个和一系列纳米线构建基于Pyroelectric的原型能量收获微型版本。关于纳米线的pyroelectric系数以及对纳米线尺寸，温度等的依赖性的实验数据将有助于对这种效果的基本理解。对单纳米线中的层状传输的基本了解可能会导致高效率能量转换设备的新范式，这些设备利用纳米级工程材料的优化，以优化pyroelectric性能。