Creating Functional Nanocrystal-Molecule Interfaces for Spin-triplet Energy Transfer

创建用于自旋三重态能量转移的功能纳米晶体分子界面

• 批准号: 2003735
• 负责人: Sean Roberts
• 金额: $ 45万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2003735&HistoricalAwards=false
• 关键词: Creating; Functional; Nanocrystal; Molecule; Interfaces

The Macromolecular, Supramolecular, and Nanochemistry Program in the Chemistry Division supports Professor Sean T. Roberts at the University of Texas at Austin to study light-triggered processes that occur in materials. Light provides the energy that fuels plant growth via photosynthesis, is used in electronics for wireless communication, and even forms the basis for noninvasive medical treatments, such as photodynamic therapy used to treat cancer. However, light transmits its energy in a peculiar manner, via particles known as photons. Different colors of light contain photons with different amounts of energy, and it is important that photon energies be matched to their intended applications. Photons with too little energy are unable to meet their intended task while photons with too much energy waste energy and can cause damage to components. This research project develops materials that reshape light’s energy content by combining pairs of photons into a single high-energy one or converting individual photons into multiple lower-energy photons. Once formed, these materials can serve as energy transfer agents improving solar energy harvesting and quantum computation. In addition to working with students closely on the research projects, Professor Roberts also founded and participates in the GReen Energy At Texas (GREAT) program, which was formed between the University of Texas at Austin and Austin Community College. GREAT aims to increase the number of community college student that earn degrees through targeted mentorship and research experiences.Semiconductor quantum dots chemically functionalized with organic dye molecules offer an ideal interface for photon conversion. Quantum dots energized by light absorption can pass their energy to molecules at their surface, promoting them into spin-triplet exciton states. If formed in high quantity, pairs of spin-triplet excitons can undergo triplet fusion, a process that combines their energy to form a single high-energy spin-singlet state that can radiate light. Likewise, photoexciting the dye molecules can fuel triplet fusion’s inverse process, singlet fission, which creates pairs of triplet excitons that can each pass to the quantum dot to drive infrared light emission. These schemes require a key step, the transfer of a spin-triplet exciton across the quantum dot:molecule interface, yet an understanding of how the structure of these interfaces impacts the rate and efficiency of spin-triplet exciton transfer is elusive. To address this need, Professor Roberts at the University of Texas at Austin directs a team that employs controlled chemical synthesis, 2D NMR and femtosecond time-resolved spectroscopies, and electronic structure calculations. The research team investigates how the chemical structure of quantum dot:molecule interfaces formed by two complementary quantum dot materials of PbS and Si impact spin-triplet exciton transfer. This project contributes to the creation of new hybrid organic:inorganic junctions for light-driven production of energy and fuels as well as materials that use spin entanglement for quantum computation and information storage.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.

化学系的大分子、超分子和纳米化学项目支持肖恩·T.罗伯茨在得克萨斯大学奥斯汀分校研究光引发的过程中发生的材料。 光通过光合作用为植物生长提供能量，用于无线通信的电子产品，甚至形成非侵入性医疗的基础，例如用于治疗癌症的光动力疗法。然而，光以一种特殊的方式传输能量，通过称为光子的粒子。不同颜色的光包含具有不同能量的光子，光子能量与其预期应用相匹配非常重要。能量太少的光子无法完成其预期任务，而能量太多的光子会浪费能量并可能对组件造成损坏。该研究项目开发的材料通过将成对的光子组合成单个高能量光子或将单个光子转换为多个低能量光子来重塑光的能量含量。一旦形成，这些材料可以作为能量转移剂，改善太阳能收集和量子计算。除了与学生密切合作的研究项目，罗伯茨教授还创立并参与了在得克萨斯州（GREAT）计划，这是在奥斯汀和奥斯汀社区学院得克萨斯大学之间形成的绿色能源。 GREAT旨在通过有针对性的指导和研究经验增加社区大学学生获得学位的数量。用有机染料分子化学功能化的半导体量子点为光子转换提供了理想的界面。由光吸收激发的量子点可以将能量传递给表面的分子，使它们进入自旋三重态激子态。如果大量形成，成对的自旋三重态激子可以经历三重态融合，这是一个将它们的能量结合起来形成一个可以辐射光的高能自旋单重态的过程。同样，光激发染料分子可以促进三重态聚变的逆过程，即单重态裂变，这会产生成对的三重态激子，每个激子都可以传递到量子点以驱动红外光发射。这些方案需要一个关键步骤，即自旋三重态激子在量子点：分子界面上的转移，但对这些界面的结构如何影响自旋三重态激子转移的速率和效率的理解是难以捉摸的。为了满足这一需求，德克萨斯大学奥斯汀分校的罗伯茨教授领导了一个团队，该团队采用受控化学合成，2D NMR和飞秒时间分辨光谱以及电子结构计算。研究小组研究了PbS和Si两种互补量子点材料形成的量子点的化学结构：分子界面如何影响自旋三重态激子转移。该项目致力于创造新的混合有机：无机结，用于光驱动的能源和燃料生产，以及利用自旋纠缠进行量子计算和信息存储的材料。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Research-Focused Approach for Introducing Undergraduate Students to Aromatic Organic Synthesis at a Community College

在社区学院向本科生介绍芳香族有机合成的以研究为中心的方法

• DOI: 10.1021/acs.jchemed.2c00662
• 发表时间: 2023
• 期刊: Journal of Chemical Education
• 影响因子: 3
• 作者: Boette, Jessica T.;Daniel, Kira M.;Lietzke, Josephine W.;Amorde, Shawn M.;Roberts, Sean T.
• 通讯作者: Roberts, Sean T.