Understanding Thermal Energy Scavenging in All-Inorganic Perovskite Nanocrystals

了解全无机钙钛矿纳米晶体的热能清除

• 批准号: 2131408
• 负责人: Simon North
• 金额: $ 46.5万
• 依托单位: Texas A&M University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-11-01 至 2024-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2131408&HistoricalAwards=false
• 关键词: Understanding; Thermal; Energy; Scavenging; Inorganic

NON-TECHNICAL SUMMARY:The industrial revolution was enabled by heat engines that perform work by converting thermal energy (heat or high temperature) to mechanical energy. Recently, several advantages have been theorized for heat engines that do work by converting heat into light, similar to how traditional engines use fluids or gases such as steam. However, there are very few known optical materials that can efficiently convert heat to optical energy, in part because heat degrades their optical performance. This project will prepare new classes of materials with precise structural and chemical properties on the nanoscale to allow for efficient conversion between thermal and light energy. The research team will examine how increasing the thermal energy in these materials can also result, unusually, in an increase of the energy of light that they emit. This phenomenon can ultimately lead to significantly more efficient heat engines with no moving parts, better solar cells, or new methods of refrigeration that do not require compressed gasses or mechanical components. The project will support graduate and undergraduate research students working in the PI’s laboratory as well as the development of novel curricula and technological tools for teaching large-format freshman chemistry courses. The primary investigator will refine some of the best innovations developed during the pandemic and take advantage of these for the transition back to classroom instruction.TECHNICAL SUMMARY:This project will study thermal energy scavenging by one-photon optical upconversion, also known as anti-Stokes photoluminescence. Upconversion results when heated photoluminescent materials emit band-edge photons during subgap excitation, while simultaneously decreasing in temperature. Inorganic lead halide perovskite nanocrystals are a champion materials system for efficient one-photon upconversion, but fundamental details of the mechanism are unknown, impeding rational strategies for further development. Spectroscopic studies conducted by the PI’s team will elucidate a clear mechanism for optical up-conversion, as well as outline the structure-property relationships that define the absorption cross section, bandwidth, temperature response, and the fundamental limits on efficiency. The research team will vary composition and morphology during nanocrystal synthesis. Structural parameters such as crystal phase, shape, and surface-to-volume ratio will be tracked using high resolution transmission electron microscopy, and powder X-ray diffractometry. In parallel, the team will perform photoluminescence excitation spectroscopy and photoluminescence lifetime studies. These experiments will quantify the dependence on above-gap or below-gap excitation wavelength, power density, and nanocrystal temperature to identify the unique states that mediate the interconversion of vibrational and electronic excitations, while preserving the intrinsic, near-ideal luminescence efficiency of the nanocrystals. The overarching goal is to understand the thermal energy scavenging properties of inorganic lead halide perovskite nanocrystals to create luminescent materials that can aid thermal-to-optical energy conversion, optical up-conversion, and optically driven refrigeration.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：通过将热能（热量或高温）转换为机械能的热发动机实现了工业革命。最近，用于通过将热量转换为光线的加热发动机的理论上，类似于传统发动机如何使用液体或气体（例如蒸汽）。但是，很少有已知的光学材料可以有效地将热量转化为光能，部分原因是热量会降低其光学性能。该项目将在纳米级上准备具有精确结构和化学特性的新型材料，以允许在热能和光能之间有效转化。研究小组将检查这些材料中的热能如何在增加它们发出的光能的情况下如何产生。这种现象最终会导致没有运动部件，更好的太阳能电池或不需要压缩气体或机械组件的新的制冷方法，而没有运动部件，更好的太阳能电池或新的制冷方法。该项目将支持在PI实验室工作的毕业生和本科研究专业的研究生，以及开发新的课程和技术工具，用于教授大型新生化学课程。主要研究者将完善大流行期间开发的一些最佳创新，并利用这些创新，以转换回课堂教学。技术摘要：该项目将研究一个单photon光学上流转换的热能清除，也称为抗螺旋发光的光致发光。当加热的光致发光材料在子仪兴奋期间散发带边缘照片时，会产生上转换，同时降低温度。无机铅卤化物钙钛矿纳米晶体是一种冠军材料系统，用于有效的一光量升级，但该机制的基本细节是未知的，阻碍了进一步发展的理性策略。 PI团队进行的光谱研究将阐明一种明确的光学上转换机制，并概述了定义抽象横截面，带宽，温度响应以及效率的基本限制的结构范围关系。研究小组将在纳米晶体合成过程中改变组成和形态。将使用高分辨率透射电子显微镜和粉末X射线衍射法跟踪结构参数，例如晶相，形状和表面体积比。同时，团队将执行光致发光兴奋光谱和光致发光寿命研究。这些实验将量化对差距或低于间隙兴奋的波长，功率密度和纳米晶体温度的依赖性，以识别介导振动和电子兴奋的互连的独特状态，同时保留纳米晶体的固有，近乎理想的近距离发光效率。总体目标是了解无机铅卤化物钙钛矿纳米晶体的热能清除特性，以创建可以帮助热能转换，光学上流转换和光学驱动的折磨的发光材料，并通过评估NSF的法定委员会进行了评估。

项目成果

Quantifying Order during Field-Driven Alignment of Colloidal Semiconductor Nanorods

胶体半导体纳米棒场驱动排列期间的量化顺序

• DOI: 10.1021/acsnano.1c08488
• 发表时间: 2022
• 期刊: ACS Nano
• 影响因子: 17.1
• 作者: Ratnaweera, Rivi J.;Rodríguez Ortiz, Freddy A.;Gripp, Nicholas J.;Sheldon, Matthew T.
• 通讯作者: Sheldon, Matthew T.