Materials World Network: Nano-Structured InGaN Solar Cells Program

材料世界网：纳米结构InGaN太阳能电池项目

• 批准号: 1108450
• 负责人: Fernando Ponce
• 金额: $ 42万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1108450&HistoricalAwards=false
• 关键词: Materials; World; Network; Nano; Structured

There is a worldwide effort to increase power generation through solar cells, to meet targets in reducing greenhouse gases. One requirement is for high efficiency multijunction solar cells (MJSCs) to extract power from concentrated solar power (CSP) plants, which are expected to become central to the delivery of solar power to national and super-grid systems. At present, such MJSCs must combine different materials systems and are usually limited by the requirement to lattice-match the individual cells to avoid efficiency losses due to defects. This effort aims to circumvent these problems by investigating solar cells based on InxGa1-xN, which has a direct band gap of 0.7-3.4 eV, spanning most of the visible spectrum, thus promising MJSCs from a single materials system. To avoid the problems of lattice mismatch and of material quality, which limit prototype solar cells based on InxGa1-xN epilayers to low x (x0.3), the investigators grow the InxGa1-xN in nanorod form, merging the nanorods using methods already developed to provide a solar cell template. The team assembled, which combines complementary expertise in growth and device fabrication (U. Nottingham), structural characterization (U. Bristol), and nanoscale optical and electrical characterization (Arizona State U.) and solar cell design and characterization (in collaboration with NREL), aims to explore the properties of InxGa1-xN single junction cells over the full composition range (0x1), with the UK participants receiving support from the Engineering and Physical Sciences Council of the UK. The team examines key fundamental properties of InxGa1-xN nanorods, using transmission and scanning electron microscopy to determine the materials requirements for growing defect-free InxGa1-xN nanorod arrays, and overcoming the problem of lattice mismatch. The work also examines the electronic properties of InxGa1-xN nanorods using novel cathodoluminescence and electron holography studies, and time-resolved photoluminescence. Single junction solar cells will be fabricated and characterized for InxGa1-xN nanorods with low and high In content, and exploratory work will be carried out into a novel two-junction nanorod cell including a tunnel junction, thus establishing the requirements for the future development of InxGa1-xN MJSC devices. The work aims to establish InGaN as a basis for (a) photovoltaics across the entire visible spectrum and (b) high efficiency MJSCs needed for CSP plants, by using a novel nanorod geometry to overcome the materials limitations that affect continuous InGaN epilayers. The team assembled brings together leading groups with a unique combination of expertise and techniques designed to clarify the key materials issues, including the fundamental properties of the nanorods and of prototype solar cells. As public science literacy is critical to the development of sound policy, project education/outreach efforts include contributions to the Arizona State University's "Science is Fun" program to develop a 45-60 minute lesson suitable for students in grades 4th through 12th. The objective is to (i) increase student interest in science and engineering and encourage the pursuit of advanced education in related technical fields, and (ii) elucidate how intellectual innovations can impact future efficient use of renewable energy, and help develop human infrastructure for the high-technology industry in Arizona. A new course on materials for nano-structured photovoltaic devices is also developed at Arizona State University to be included in the curriculum of the newly established Science Master's in Nanoscience program.

全球范围内都在努力通过太阳能电池增加发电量，以实现减少温室气体排放的目标。其中一项要求是高效多结太阳能电池（MJSC）从聚光太阳能发电（CSP）发电厂提取电力，预计这些发电厂将成为向国家和超级电网系统输送太阳能的核心。目前，此类 MJSC 必须结合不同的材料系统，并且通常受到对单个电池进行晶格匹配的要求的限制，以避免由于缺陷而导致效率损失。这项工作旨在通过研究基于 InxGa1-xN 的太阳能电池来规避这些问题，InxGa1-xN 的直接带隙为 0.7-3.4 eV，跨越大部分可见光谱，因此有望通过单一材料系统实现 MJSC。为了避免晶格失配和材料质量问题（这些问题将基于 InxGa1-xN 外延层的原型太阳能电池限制为低 x (x0.3)），研究人员以纳米棒形式生长 InxGa1-xN，并使用已经开发的方法合并纳米棒提供太阳能电池模板。该团队汇集了生长和器件制造（诺丁汉大学）、结构表征（布里斯托尔大学）、纳米级光学和电学表征（亚利桑那州立大学）以及太阳能电池设计和表征（与 NREL 合作）方面的互补专业知识。 ），旨在探索 InxGa1-xN 单结电池在整个成分范围（0x1）内的特性，英国参与者得到了英国工程和物理科学委员会的支持。该团队研究了 InxGa1-xN 纳米棒的关键基本特性，使用透射和扫描电子显微镜来确定生长无缺陷 InxGa1-xN 纳米棒阵列的材料要求，并克服晶格失配问题。这项工作还利用新型阴极发光和电子全息研究以及时间分辨光致发光研究了 InxGa1-xN 纳米棒的电子特性。将针对低In含量和高In含量的InxGa1-xN纳米棒制备和表征单结太阳能电池，并对包含隧道结的新型双结纳米棒电池进行探索工作，从而确定未来发展的要求InxGa1-xN MJSC 器件。这项工作旨在通过使用新型纳米棒几何形状克服影响连续 InGaN 外延层的材料限制，将 InGaN 建立为 (a) 整个可见光谱范围内的光伏发电和 (b) CSP 工厂所需的高效 MJSC 的基础。该团队汇集了领先的团队，他们拥有独特的专业知识和技术组合，旨在阐明关键材料问题，包括纳米棒和原型太阳能电池的基本特性。由于公共科学素养对于制定健全的政策至关重要，因此项目教育/推广工作包括为亚利桑那州立大学的“科学很有趣”计划做出贡献，以开发适合 4 至 12 年级学生的 45-60 分钟课程。 其目标是（i）提高学生对科学和工程的兴趣，鼓励在相关技术领域接受高等教育，（ii）阐明智力创新如何影响未来可再生能源的有效利用，并帮助发展人类基础设施亚利桑那州的高科技产业。 亚利桑那州立大学还开发了关于纳米结构光伏器件材料的新课程，并将其纳入新设立的纳米科学理学硕士项目的课程中。