Quintuple P-N Junction Nanowires for Wireless Water Splitting in Particle Suspension Reactors

用于颗粒悬浮反应器中无线水分解的五重 P-N 结纳米线

• 批准号: 1914711
• 负责人: James Cahoon
• 金额: $ 40.5万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1914711&HistoricalAwards=false
• 关键词: Quintuple; Junction; Nanowires; Wireless; Water

The inexpensive generation of hydrogen from water using sunlight ("photocatalytic water splitting") would provide an abundant source of renewable fuel. High efficiency solar water splitting reactors will require new types of photocatalytic materials and advanced reactor designs. Silicon is the second most abundant element in the Earth's crust, is non-toxic, and is the basis for nearly all modern electronics. This research project will explore a way to use silicon in photocatalytic water splitting by way of elongated particles ("nanowires") suspended in water. These nanowires will be grown using a chemical process that enables hundreds of millions of nanowires to be created at once with a size that is 100-1000 times smaller than a human hair. Although these particles are small, they have a complex internal structure. When illuminated with light, the internal structure allows the wires to generate a voltage similar to the that of AA or AAA batteries. This research project will explore the fundamental aspects of the growth of silicon nanowires and will examine how the design of the structures affects the light absorbed and the voltage generated. The ability of these particles to perform chemical reactions when suspended in water, using the voltage induced by light, will be tested in a novel reactor design. This project will also provide research experiences and training for students from the high school through graduate school level and will provide multiple opportunities for the public to learn about photocatalytic water splitting. The results should open the door to new technological applications of silicon that are made possible by the control of particle size and composition at a microscopic scale. Particle suspension reactors, in which photoactive nanoparticles are suspended in water, are a potentially low-cost design for solar-driven photoelectrochemical water splitting to produce affordable hydrogen. To realize this device architecture, the development of a photoactive nanoparticle that both produces enough voltage and absorbs a broad spectrum of visible to near-infrared light is needed. This research project will address the synthesis and development of silicon nanowires that can be encoded with an arbitrary number of p-i-n junctions to produce large photovoltages in excess of the 1.23 V thermodynamic potential needed for water splitting. The multijunction silicon nanowires are synthesized by metal-catalyzed growth using the vapor-liquid-solid (VLS) growth mechanism, and p-n or p-i-n junctions are formed by in situ modulation of dopants as the nanowire grows. The goal of this research project is to perform fundamental studies on the growth, processing, and properties of single nanowires to enable the design of high-performance quintuple p-i-n junction nanowires that can be used for water splitting. In this structure, each of the five junctions must individually operate as an efficient solar cell, and in addition, they must each be connected in series by an efficient tunnel junction. In addition to the synthesis of axial p-(p-i-n)x-n nanowires, where x ranges from 1 to 15 junctions, the project will employ a combined experimental and computational evaluation of single-nanowire photovoltaic performance. Both the electrical performance and light absorption characteristics will be evaluated, and the results will feed back into the synthesis and design of structures. Proof-of-concept single-nanowire water splitting devices and particle suspension reactors will be developed for initial evaluation of the proof of concept.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.

使用阳光（“光催化水分”）从水中廉价的氢生成将提供丰富的可再生燃料来源。 高效的太阳能水分拆分反应器将需要新型的光催化材料和高级反应器设计。 硅是地壳中第二大元素，无毒，并且是几乎所有现代电子产品的基础。该研究项目将探索一种通过悬浮在水中的细长颗粒（“纳米线”）进行光催化水分裂中的方法。 这些纳米线将使用化学过程生长，该化学过程使数亿纳米线的大小比人的头发小100-1000倍。 尽管这些颗粒很小，但它们具有复杂的内部结构。当用光照射时，内部结构允许电线产生类似于AA或AAA电池的电压。该研究项目将探讨硅纳米线增长的基本方面，并将研究结构的设计如何影响吸收的光和产生的电压。这些颗粒在悬浮在水中（使用光引起的电压）进行化学反应的能力将在新型的反应器设计中进行测试。该项目还将通过研究生院层面为来自高中的学生提供研究经验和培训，并为公众提供多种机会，以了解催化水的分裂。结果应打开硅新技术应用的大门，这些技术是通过微观尺度控制粒径和组成而成为可能的。颗粒悬架反应器，其中光活性纳米颗粒被悬浮在水中，是一种潜在的低成本设计，用于太阳能驱动的光电化学水分裂以产生负担得起的氢。为了实现这种设备架构，需要产生足够的电压并吸收近红外光的光活性纳米颗粒的开发。该研究项目将解决硅纳米线的合成和开发，可以用任意数量的P-I-N连接来编码，以产生超过水分流所需的1.23 V热力学潜力的大型光电压。使用蒸气 - 液体 - 固体（VLS）生长机制通过金属催化的生长合成多期硅纳米线，而P-N或P-I-N交界处是通过将掺杂剂作为纳米线生长的原位调节而形成的。该研究项目的目的是对单纳米线的生长，加工和特性进行基础研究，以使可以用于水分拆分的高性能Quintuple P-i-N结纳米线的设计。在这种结构中，五个连接中的每个结构都必须单独作为有效的太阳能电池，此外，它们必须由有效的隧道连接串联连接。除了轴向p-（p-i-n）X-N纳米线的合成外，X范围从1到15个连接范围，该项目还将采用单纳米线光伏性能的合并实验和计算评估。将评估电性能和光吸收特征，结果将反馈到结构的合成和设计中。概念验证单纳米线分裂设备和粒子悬架反应器将被开发以初步评估概念证明。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子和更广泛影响的评估标准来通过评估来获得支持的。

项目成果

Influence of Geometry on Quasi-Ballistic Behavior in Silicon Nanowire Geometric Diodes

• DOI: 10.1021/acsanm.2c04666
• 发表时间: 2023-03
• 期刊: ACS Applied Nano Materials
• 影响因子: 5.9
• 作者: Kelly L. White;Max A. Umantsev;Jeremy D. Low;James P. Custer;J. Cahoon

Water splitting with silicon p–i–n superlattices suspended in solution

悬浮在溶液中的硅p-i-n超晶格的水分解

• DOI: 10.1038/s41586-022-05549-5
• 发表时间: 2023
• 期刊: Nature
• 影响因子: 64.8
• 作者: Teitsworth, Taylor S.;Hill, David J.;Litvin, Samantha R.;Ritchie, Earl T.;Park, Jin-Sung;Custer, James P.;Taggart, Aaron D.;Bottum, Samuel R.;Morley, Sarah E.;Kim, Seokhyoung
• 通讯作者: Kim, Seokhyoung