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.

利用阳光从水中生产氢的廉价方法（“光催化水分解”）将提供丰富的可再生燃料来源。高效的太阳能水分解反应器需要新型的光催化材料和先进的反应器设计。硅是地壳中含量第二丰富的元素，它是无毒的，是几乎所有现代电子产品的基础。该研究项目将探索一种方法，通过悬浮在水中的细长颗粒（“纳米线”），将硅用于光催化水分解。这些纳米线将使用一种化学方法来生长，这种方法可以一次制造出数亿根纳米线，其尺寸比人类头发小100-1000倍。虽然这些颗粒很小，但它们具有复杂的内部结构。当光线照射时，内部结构允许导线产生类似于AA或AAA电池的电压。该研究项目将探索硅纳米线生长的基本方面，并将研究结构的设计如何影响吸收的光和产生的电压。这些粒子悬浮在水中时，利用光感应的电压进行化学反应的能力，将在一种新型反应堆设计中进行测试。该项目还将为从高中到研究生阶段的学生提供研究经验和培训，并将为公众提供多种了解光催化水分解的机会。这一结果将为硅的新技术应用打开大门，这些应用将通过在微观尺度上控制颗粒大小和组成而成为可能。粒子悬浮反应器，其中光活性纳米粒子悬浮在水中，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解，以产生负担得起的氢。为了实现这种器件结构，需要开发一种光活性纳米粒子，它既能产生足够的电压，又能吸收广谱的可见光到近红外光。该研究项目将致力于硅纳米线的合成和开发，该纳米线可以编码任意数量的p-i-n结，以产生超过水分解所需的1.23 V热力学势的大光伏。采用气-液-固（VLS）生长机制，通过金属催化生长合成了多结硅纳米线，并在纳米线生长过程中通过掺杂剂的原位调制形成了p-n或p-i-n结。该研究项目的目标是对单纳米线的生长、加工和性能进行基础研究，从而设计出可用于水分解的高性能五元p-i-n结纳米线。在这种结构中，五个结中的每一个都必须作为一个高效的太阳能电池单独运行，此外，它们必须通过一个高效的隧道结串联起来。除了轴向p-(p-i-n)x-n纳米线的合成，其中x的范围从1到15个结，该项目将采用单纳米线光伏性能的实验和计算相结合的评估。电性能和光吸收特性都将被评估，结果将反馈到结构的合成和设计中。将开发概念验证的单纳米线水分解装置和颗粒悬浮反应器，以进行概念验证的初步评估。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。

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