Collaborative Research: Low Cost, High Performance Ultrathin GaAs Solar Cells for Terrestrial Photovoltaics

摘要：用于地面光伏的低成本、高性能超薄砷化镓太阳能电池非技术性：尽管其令人印象深刻的性能接近理论极限，但砷化镓太阳能电池在地球应用中的实际应用仍然是一个巨大的挑战，这主要是由于生长器件质量的外延材料的成本过高。这项建议中概述的研究旨在通过开发一种实用的解决方案来解决全球社会未来的能源需求，该解决方案能够平衡砷化镓太阳能电池的高性能及其生产成本，从而使其能够在地面光伏中大规模部署。拟议研究的高度多学科主题将与全面的教学和外联工作密切结合。PiYoon将与南加州大学工程多样性中心合作，为洛杉矶市中心教育困难的初中生和高中生建立实验室实习机会。共同派·李将在两个特别的项目上与耶鲁科学外展合作：面向家庭和公众的周六科学项目，以及面向初中生和高中生的科学之路项目。培训本科生和研究生研究人员将是主要的教育目标，在这方面，私人投资机构将继续支持和鼓励女学生和来自代表性不足群体的学生更广泛地参与。技术：这项合作研究的目标是展示高性能、具有成本竞争力的砷化镓太阳能电池在陆地光伏领域的大规模部署。为了实现这一目标，我们将开发新的材料生长和器件制造策略，利用(1)能够有效利用昂贵源材料的超薄器件平台，(2)可以显著降低外延材料成本的多层外延生长，(3)可以增强吸收的双面纳米光子操纵，(4)允许在低成本基板上大面积分布的高产量印刷技术。具体地说，任务1将探索在分子束外延(MBE)中生长超薄GaAs太阳能电池的多个器件堆栈，目标是多层生长的外延堆栈的均匀材料特性和器件性能。任务2将寻求建立对超薄GaAs太阳能电池的外延设计的基本理解和优化，以增强载流子收集和最大限度地提高光捕获的有效性。任务3将重点开发用于光捕获和光子回收的双面光子管理的综合方案。拟议研究的成功完成将有助于开发用于陆地应用的高性能、经济可行的GaAs太阳能电池，还将加强对以下方面的基本认识：分子束外延生长的多层外延组件中的材料行为和掺杂扩散；用于最高效光伏能源转换的超薄GaAs太阳能电池的优化层结构；用于最大限度地提高光学薄吸收体光吸收的多功能光学设计。

Abstract:Low Cost, High Performance Ultrathin Gallium Arsenide Solar Cells for Terrestrial PhotovoltaicsNontechnical: Despite their impressive performance reaching near the theoretical limit, the practical application of gallium arsenide solar cells in on-earth applications remains a formidable challenge largely due to the excessively high cost of growing device-quality epitaxial materials. The research outlined in this proposal aims to address the future energy demand of global society by developing a practical solution that can balance the high performance of gallium arsenide solar cells with their production cost, and therefore enable their large-scale deployment in terrestrial photovoltaics. The highly multidisciplinary themes of the proposed research will be intimately integrated with comprehensive teaching and outreach efforts. PI Yoon will work with the Center for Engineering Diversity at the University of Southern California to establish laboratory internship opportunities for educationally-disadvantaged middle and high school students in the inner city of Los Angeles. Co-PI Lee will partner with Yale Science Outreach on two particular programs: Science on Saturdays for families and the general public and the Pathways to Science program for middle and high school students. Training both undergraduate and graduate student researchers will be a primary educational goal, where the PIs will continue to support and encourage broadening participation of female students and students from underrepresented groups. Technical:The goal of this collaborative research is to demonstrate high performance, cost-competitive GaAs solar cells for their large-scale deployment in terrestrial photovoltaics. To achieve this goal, we will develop novel strategies of materials growth and device fabrication exploiting (1) an ultrathin device platform that enables efficient use of expensive source materials, (2) multilayer epitaxial growth that can significantly reduce the cost of epitaxial materials, (3) bifacial nanophotonic light manipulation that can enhance the absorption, (4) high yield printing techniques that permits large-area distribution over low cost substrates. Specifically, Task 1 will explore the growth of multiple device stacks of ultrathin GaAs solar cells in molecular beam epitaxy (MBE) targeting uniform materials properties and device performance of multilayer-grown epitaxial stacks. Task 2 will seek to establish fundamental understanding and optimization of the epitaxial design for ultrathin GaAs solar cells to enhance the carrier collection and maximize the effectiveness of light trapping. Task 3 will focus on developing integrated schemes of bifacial photon management for light trapping and photon recycling. Successful completion of the proposed research will lead to the development of high performance, economically viable GaAs solar cells for terrestrial applications and also strengthen fundamental understanding of: materials behaviors and dopant diffusion in MBE-grown multilayer epitaxial assemblies; optimized layer structures of ultrathin GaAs solar cells for the most efficient photovoltaic energy conversion; multifunctional optical designs for maximized light absorption in the optically thin absorber.