US Egypt Cooperative Research: Mixed Oxide Nanotube Arrays for Solar Energy Conversion: Materials Optimization, Charge Carrier Dynamics and Photothermal Characteristics

1103827 该项目支持亚特兰大格鲁吉亚理工学院（格鲁吉亚Tech）的Mostafa El-Sayed博士和埃及开罗国家研究中心（NRC）的Nahla Abdel-Salam博士的合作研究项目。 参与合作的还有埃及开罗Ain Shams大学（ASU）的Hasan Talaat博士。 他们计划研究用于太阳能转换的混合氧化物纳米管阵列：材料优化，电荷载流子动力学和光热特性。智力优点：基于廉价、丰富和环境友好的金属氧化物纳米材料的高性能、经济实惠和空气稳定的无机光伏和光电化学器件的构建将实现长期和可扩展的太阳能转换。这一领域的发展虽然令人鼓舞，但未能大规模部署利用可再生能源的新技术。对染料和量子点敏化太阳能电池的电子性质的基础研究还没有跟上金属氧化物纳米纤维的最新进展。 此外，还没有努力确定损耗机制并量化太阳能电池中产生的热量，这对性能和稳定性至关重要，特别是在一维纳米材料中。这项工作将扩展各种金属氧化物的独特优势的1D纳米结构的合成和优化，并将其用于太阳能转换设备，同时考虑电流（光电子）和氢气（通过氢气）的生产。方面包括材料优化，通过使用混合氧化物纳米architectures以及新的合成路线，光电流测量，监测动态的电荷载流子与超快瞬态吸收，和量化的热量在操作过程中产生的光热光谱。其目的是寻找转换效率与放出的热量或载流子动力学之间的相关性，并使用它来指导对材料组成或合成方法的修改，以获得最大的转换效率。所观察到的相关性可能有助于理解这种设备的操作过程中的转换过程的基本机制。 通过系统地探索金属氧化物掺杂以降低电极带隙并提高电导率以及使用各种敏化剂来提高光吸收，将满足基本和技术挑战。物理研究将考虑转换为燃料或电力的能量以及损失为热量的能量。在同一个研究团队中将材料优化和基本表征相结合，是加强国际合作的一种新颖解决方案。该项目将联合收割机三个研究小组在各自领域的经验：纳米颗粒和纳米管合成和超快动力学（格鲁吉亚理工学院），材料合成和表征（NRC）和光热测量（ASU）。更广泛的影响：这项研究可以导致太阳能的重大技术进步，对世界社会产生重大影响。由于对更多可再生能源的需求是全球性的，拟议的工作将与埃及科学家合作开展，以增加两国以及更广泛世界的培训，经验，意识，技术和资源。 关键的实验工作将由美国和埃及的初级科学家、博士后和研究生进行。博士后和初级科学家将负责实验规划，并将在国际合作中获得重要经验。科学家将在各国之间旅行，交流知识和材料，举办讲座，并加强国际合作。El-Sayed博士通过国家纳米技术基础设施网络青年外展计划与高中生会面，这项工作将突出显示。这项建议得到了美国-埃及联合基金计划的支持，NSF支持美国方面，埃及政府资助埃及方面。

1103827 This project supports a cooperative research project by Dr. Mostafa El-Sayed at Georgia Institute of Technology (Georgia Tech) in Atlanta and Dr. Nahla Abdel-Salam at the National Research Center (NRC) in Cairo, Egypt. Included in the collaboration is Dr. Hasan Talaat of Ain Shams University (ASU), Cairo, Egypt. They plan to study Mixed Oxide Nanotube Arrays for Solar Energy Conversion: Materials Optimization, Charge Carrier Dynamics and Photothermal Characteristics. Intellectural Merit: The construction of high-performance, affordable, and air-stable inorganic photovoltaic and photoelectrochemical devices based on metal oxide nanomaterials which are cheap, abundant and environmentally benign will enable long-term and scalable solar energy conversion. Developments in this area, although encouraging, have failed to achieve wide-scale deployment of new technology to harness renewable energy. Fundamental studies on the electronic properties of dye- and quantum-dot-sensitized solar cells have not kept up with recent advances in nanofabrication of metal oxides. Additionally, efforts to identify loss mechanisms and quantify the amount of heat produced in solar cells, critical to performance and stability, have not been made, particularly in 1D nanoscale materials. This work will extend the synthesis and optimization of uniquely advantageous 1D nano-architectures of various metal oxides and employ them to solar energy conversion devices, considering the production of both current (photovoltaics) and hydrogen (through photocatalysis). Aspects include materials optimization through the use of mixed oxide nano-architechtures as well as new synthetic routes, photocurrent measurements, monitoring the dynamics of charge carriers with ultrafast transient absorption, and quantification of the amount of heat generated during the operation by photothermal spectroscopy. The aim is to look for correlation between the conversion efficiency and the heat evolved or the carrier dynamics and use it to guide modifications to the material composition or method of synthesis for maximum conversion efficiency. The observed correlation may help in understanding the basic mechanism of the conversion process during the operation of such devices. Fundamental and technological challenges will be met by systematically exploring metal oxide doping to lower the electrode bandgap and improve conductivity as well as the use of various sensitizers to improve light absorption. Physical investigations will consider both the energy converted to fuel or electricity as well as the energy lost to heat. This combination of material optimization and fundamental characterization within the same research team is a novel solution to enhance international collaboration. This project will combine the three research groups with experience in their respective areas: nanoparticle and nanotube synthesis and ultrafast dynamics (Georgia Tech.), materials synthesis and characterization (NRC), and photothermal measurements (ASU). Broader Impact: The research can lead to major technological advances in solar energy with major impacts on world societies. As the need for more renewable energy sources is global, the proposed work will be carried out in collaboration with scientists from Egypt, to increase the training, experience, awareness, technology, and resources of both countries as well as the wider world. Key experimental work will be conducted by junior scientists, postdocs, and graduate students in the U.S. and also in Egypt. Postdocs and junior scientists will be responsible for experimental planning, and will gain vital experience in international collaborations. Scientists will travel between countries to exchange knowledge and materials, give lectures, and improve international cooperation. Dr. El-Sayed meets with high-school students through the National Nanotechnology Infrastructure Network youth outreach program and this work will be featured prominently.This proposal is supported under the US-Egypt Joint Fund Program where NSF supports the US side and the Government of Egypt funds the Egyptian side.