Maximizing the Harvesting of Photogenerated Electron-Hole Pairs in Hybrid Plasmonic Nanosystems

在化学系大分子、超分子和纳米化学项目（MSN）的支持下，伊利诺伊大学香槟分校的Prashant Jain教授正在开发从太阳辐射中捕获可见光的材料、原理和策略，并以定向和节能的方式将其部署，形成高价值的化学键。一个特殊的目标是在许多高价值化学品中发现的氮和碳原子之间的化学键。目前，这种光收集是通过纳米尺度的铸造金属颗粒实现的；然而，光能到化学能的转换是低效和不受控制的。Jain教授正在解决这一挑战，他使用纳米级的氧化矿物来吸收可见光，并产生能量电荷，这些电荷可以存活足够长的时间，以有效地用于化学能的产生。此外，他还将这些吸光材料与指导和促进电荷流动的化学试剂配对。如果研究成功，将开发出利用可再生能源制造高能试剂、燃料和精细化学品的技术，而且不会产生碳排放。在公共宣传活动中，Jain教授还通过太阳能和电力从农业占主导地位的社区附近的水源中去除硝酸盐污染物，促进可持续技术和实践。参与该项目的研究生在广泛的化学合成、光谱和化学动力学分析以及催化方面获得了宝贵的经验。该项目也为对可持续技术感兴趣的本科生研究人员提供了机会。等离子体纳米结构允许以高能载流子的形式收集光，这些载流子反过来可以用来加速或驱动化学反应。然而，通过这种方案收集光和光到化学能量的转换仍然远远低于热力学效率极限。Jain教授正在应用一种新的等离子体材料和杂交策略，以最大限度地分离光产生的电子-空穴对，并更有效和有选择性地利用它们进行反应，如氮-碳键的形成。具体来说，Jain教授正在使用等离子体金属氧化物纳米结构，预计它会表现出较慢的载流子弛豫和重组。其他策略包括等离子体金属氧化物纳米结构与极性表面、水氧化促进剂和均相催化剂的杂交。这项工作有望阐明控制载体分离和提取的物理化学和材料设计因素，并阐明化学结构和方案，这些结构和方案非常适合纳米尺度上载体的定向和有效流动。这些概念加上非金属等离子体氧化物纳米结构的使用，有可能扩大等离子体化学的范围和范围，以实现与能量相关的化学转化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Macromolecular, Supramolecular and Nanochemistry Program (MSN) in the Division of Chemistry, Professor Prashant Jain of the University of Illinois Urbana-Champaign is developing materials, principles, and strategies for capturing visible light from solar radiation and deploying it in a directed and energy-efficient manner to form high-value chemical bonds. A particular target is the chemical bond between nitrogen and carbon atoms found in many high-value chemicals. Such light harvesting is currently achievable by nanometer-scale particles of coinage metals; however, the conversion of light to chemical energy is inefficient and uncontrolled. Professor Jain is addressing this challenge by using oxide minerals engineered on the nanometer scale to absorb visible light and produce energetic charges that survive long enough to be used productively for chemical energy generation. Furthermore, he is pairing these light-absorbing materials with chemical agents that direct and promote the flow of charge. If successful, the research will lead to technologies for manufacturing energetic reagents, fuels, and fine chemicals using renewable power and producing no carbon emissions. In public outreach activities, Professor Jain is also promoting sustainable technologies and practices through solar energy- and electricity-powered removal of nitrate pollutants from water sources near agriculture-dominated communities. The graduate students engaged in this project are gaining valuable experience in a wide range of chemical syntheses, spectroscopic and chemical kinetic analyses, and catalysis. This project is also providing opportunities for undergraduate researchers interested in sustainable technologies.Plasmonic nanostructures allow the harvesting of light in the form of energetic charge carriers, which can in turn be deployed to accelerate or drive chemical reactions. However, harvesting of light and light-to-chemical energy conversion via this scheme remains well below the thermodynamic efficiency limit. Professor Jain is applying a newer class of plasmonic materials and hybridization strategies for maximizing the separation of photogenerated electron–hole pairs and utilizing them more efficiently and selectively for reactions such as nitrogen–carbon bond formation. Specifically, Professor Jain is employing plasmonic metal oxide nanostructures, which are anticipated to exhibit slower carrier relaxation and recombination. The other strategies involve the hybridization of plasmonic metal oxide nanostructures with polar surfaces, water-oxidation promoters, and homogeneous catalysts. The work is expected to elucidate physicochemical and materials design factors that govern carrier separation and extraction and illustrate chemical architectures and schemes that are ideally suited for the directed and efficient flow of carriers on the nanoscale. These concepts coupled with the use of non-metallic plasmonic oxide nanostructures have the potential to expand the scope and reach of plasmonic chemistry for achieving energy-relevant chemical transformations.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.