Materials World Network: Nanostructured Materials for High-Efficiency Solar Energy Harvesting

在材料研究部门的支持下，德克萨斯大学奥斯汀分校（UT Austin）的科学家将与克劳斯塔尔理工大学（TU Clausthal）合作，探索高效光伏器件和太阳能电池组件的材料，加工和器件技术，这些器件和组件可以在广泛的光谱照明条件下提供最佳性能，如聚光光伏等应用所需。 在使用GaAs/InxGa 1-xAs 1-ySby和GaAs/InxGa 1-xAs 1-y-zSbyNz异质结构的量子阱太阳能电池中同时实现高开路电压和高光电流的材料和能带结构工程的概念将与用于在薄膜半导体层中捕获长波长光的亚波长尺度金属/电介质结构的使用相结合，从而能够增加量子阱区域中的吸收。 在TU Clausthal的外延生长和基本结构和光学材料表征将与UT Austin的异质结构建模和设计，材料和器件加工以及光学和电学表征相结合，以全面了解外延生长，材料质量，光学特性和载流子传输过程。使得能够根据需要优化光吸收和光生载流子收集，以实现对于这种器件所预测的非常高的功率转换效率。 此外，基于多层金属纳米结构阵列的“超表面”结构将在UT Austin使用化学合成的金属纳米颗粒和TU Clausthal开发的基于溶液的沉积和组装技术进行设计，制造和表征。 适当设计，这些结构将提供波长选择性反射率和透射率的偏振和入射光的角度的变化鲁棒性，并有望使高效太阳能电池组件中的太阳光光谱分裂的强大方法。 所使用的合成和制造方法将使得能够在非平面和柔性表面上进行大面积制造，如太阳光的波长选择性聚焦等应用所需。 光化学和可再生能源的概念将被纳入本科教育的水平，从一个必要的新生入门课程到高级设计项目在UT奥斯汀。 德克萨斯大学奥斯汀分校（UT Austin）的研究人员将与克劳斯塔尔理工大学（TU Clausthal）合作，探索将太阳能（阳光）高效转换为电能的材料和制造技术。 重点将放在通过将太阳光从大面积集中到小的、非常有效的太阳能电池上，从而能够将太阳能大规模转化为电能的技术上。 这种方法将允许使用纳米级量子半导体结构来提高太阳能电池的效率，并将太阳光集中到一个小区域上。它可以大大减少太阳能系统中稀有和昂贵元素的使用以及能源密集型制造工艺。 一个强大的教育组成部分，将新生电气工程教学法和指导以及早期引入太阳能和可再生能源的概念，与拟议研究相关的高级设计项目的开发，以及参与本科生的研究，特别是传统上在科学和工程中代表性不足的群体，将在UT奥斯汀实施。 UT Austin和TU Clausthal之间的合作将为研究生提供直接参与国际研究活动的机会，并接触到日益国际化的科学研究背景。

TECHNICAL SUMMARY:With support from the Division of Materials Research, scientists at the University of Texas at Austin (UT Austin) will collaborate with the Clausthal University of Technology (TU Clausthal) to explore materials, processing, and device technologies for high-efficiency photovoltaic devices and solar cell assemblies that can provide optimal performance under a broad range of spectral illumination conditions, as required for applications such as concentrating photovoltaics. Concepts for materials and band-structure engineering to realize high open circuit voltages simultaneously with high photocurrent in quantum-well solar cells using GaAs/InxGa1-xAs1-ySby and GaAs/InxGa1-xAs1-y-zSbyNz heterostructures will be combined with the use of sub-wavelength-scale metal/dielectric structures for long-wavelength light trapping in thin-film semiconductor layers, enabling increased absorption in the quantum-well regions. Epitaxial growth and basic structural and optical materials characterization at TU Clausthal will be combined with heterostructure modeling and design, materials and device processing, and optical and electrical characterization at UT Austin to develop a comprehensive understanding of epitaxial growth, material quality, optical properties, and carrier transport processes, enabling optimization of both optical absorption and photogenerated carrier collection as required to realize the very high power conversion efficiencies predicted for such devices. In addition, "metasurface" structures based on multiple layers of metal nanostructure arrays will be designed, fabricated, and characterized at UT Austin using chemically synthesized metal nanoparticles and solution-based deposition and assembly techniques developed at TU Clausthal. Appropriately designed, these structures will provide wavelength-selective reflectance and transmittance robust to variations in polarization and angle of incident light, and are expected to enable powerful approaches for spectral splitting of sunlight in high-efficiency solar cell assemblies. The synthesis and fabrication approaches used will enable large-area fabrication on non-planar and flexible surfaces as required for applications such as wavelength-selective focusing of sunlight. Photovoltaics and renewable energy concepts will be incorporated into undergraduate education at levels ranging from a required freshman introductory course to senior-level design projects at UT Austin. NON-TECHNICAL SUMMARY:Researchers at the University of Texas at Austin (UT Austin) will collaborate with the Clausthal University of Technology (TU Clausthal) to explore materials and manufacturing technologies for high-efficiency conversion of solar power (sunlight) to electrical power. Emphasis will be placed on technologies that enable large-scale conversion of solar into electrical power by focusing sunlight from a large area onto a small, very efficient solar cell. This approach will allow the use of nanoscale quantum semiconductor structures to increase the efficiency of the solar cell, and by concentrating sunlight onto a small area. it can dramatically reduce the usage of rare and expensive elements and energy-intensive manufacturing processes in solar power systems. A strong educational component, incorporating freshman electrical engineering pedagogy and mentoring as well as early introduction to concepts for solar and renewable energy, development of senior-level design projects relevant to the proposed research, and involvement in research of undergraduates, particularly from groups traditionally underrepresented in science and engineering, will be implemented at UT Austin. The collaboration between UT Austin and TU Clausthal will provide graduate students with direct involvement in international research activities and exposure to the increasingly international context of scientific research.