Probing and optimizing quantum dot confined states for next generation intermediate band solar cells

0933348约翰逊概述技术优点：中间波段（IB）太阳能电池具有将阳光转换为电能的潜力，效率创纪录。也许IB半导体最有前途的方法是量子点（QD）阵列。原则上，这些量子点阵列将取代最先进的p-i-n太阳能电池中的本征区。虽然这一概念最初是在1990年代提出的，但预期的效率记录尚未实现。到目前为止，性能一直受到限制，缺乏基本的设计规则的能量转换过程中的量子点限制状态和迷你带的背景下。特别是，量子点的形状，尺寸，应变状态，和量子点/矩阵界面的均匀性的形成和量子点限制状态和迷你带之间的相互作用的影响的理解是必要的。此外，必须开发能够实现最佳太阳光到电转换效率的新型迷你带架构。所提出的方法涉及最先进的纳米制造方法，具有前所未有的空间分辨率的测量和多尺度模拟的独特组合。这项工作的长期目标是提供一套设计规则，以优化各种纳米结构材料中的太阳光-电力转换。几个基本问题的发展至关重要的最佳太阳能-电力转换设计规则将得到解决，包括：什么是临界长度尺度与收集的点缺陷的电子状态出现类似的一个小量子点？量子点的形状和大小如何影响量子点的电子态？界面无序和应变如何影响量子点电子态的耦合，以及二维和三维量子点阵列中电子能带的形成？需要哪些迷你波段架构来优化太阳光到电力的转换效率？利用co-PI在最先进的纳米纤维、前所未有的空间分辨率测量和多尺度模拟方面的独特综合专业知识，将开发一套设计规则，以优化纳米结构中间带太阳能电池中的阳光到电力转换。更广泛的影响：这项研究预计将对能源和可持续性产生重大影响。PI还将制定能源和可持续性方面的推广计划。外展计划将在当地公立高中建立伙伴关系。这种方法将为安阿伯的合作PI制定的更雄心勃勃的外展计划奠定基础，该计划已将30多名当地高中生带到UM校园进行夏季研究实习。PI将开发一个模块，“太阳能电池材料”，将纳入现有的高中物理和化学课程。他们将向来自不同学校系统不同背景的学生展示这个互动和实践模块。该模块将利用周围的兴奋在可持续能源研究的UIUC和UM的主要新举措，并将有助于产生对工程研究的兴趣。

0933348JohnsonSummaryTechnical Merit: Intermediate-band (IB) solar cells have the potential to convert sunlight to electricity with record efficiency. Perhaps the most promising approach to IB semiconductors is quantum dot (QD) arrays. In principle, these QD arrays would replace the intrinsic region in state-of-the-art p-i-n solar cells. Although this concept was originally proposed in the 1990s, the anticipated efficiency records have yet to be achieved. The performance to date has been limited by a lack of fundamental design rules for energy conversion processes in the context of QD confined states and minibands. In particular, an understanding of the influence of QD shapes, sizes, strain states, and QD/matrix interface uniformity on the formation of and interaction between QD confined states and minibands is needed. Furthermore, novel miniband architectures which enable optimum sunlight to electricity conversion efficiencies must be developed. The proposed approach involves a unique combination of state-of-the-art nanofabrication methods, measurements with unprecedented spatial resolution, and multi-scale simulations. The long-term objective of the work is to provide a set of design rules to optimize sunlight-to-electricity conversion in a wide variety of nanostructured materials. Several fundamental questions critical to the development of optimum sunlight-to-electricity conversion design rules will be addressed, including: what is the critical length scale at which the electronic states associated with a collection of point defects appear similar to those of a small QD? How do QD shapes and sizes influence the QD electronic states? How do interfacial disorder and strain influence the coupling of QD electronic states, as well as the formation of electronic mini-bands in two-dimensional and three-dimensional QD arrays? Which miniband architectures are needed to optimize the sunlight to electricity conversion efficiency? Using the unique combined expertise of the co-PIs in state-of-the-art nanofabrication, measurements with unprecedented spatial resolution, and multi-scale simulations, a set of design rules to optimize sunlight-to-electricity conversion in nanostructured intermediate band solar cells will be developed.Broader Impact: This research is expected to have a substantial impact on energy and sustainability. The PIs will also develop an outreach program in energy and sustainability. The outreach program will build partnerships in the local public high schools. This approach will lay the groundwork for a more ambitious outreach program developed by the co-PI in Ann Arbor, which has brought more than 30 local high school students to the UM campus for summer research internships. The PIs will develop a module, 'Materials for Solar Cells", to be incorporated into existing high school physics and chemistry courses. They will present this interactive and hands-on module to students from various backgrounds within several school systems. The module will draw on the excitement surrounding major new initiatives at UIUC and UM in sustainable energy research, and will serve to generate interest in engineering research.