SEP Collaborative: Routes to Earth Abundant Kesterite-based Thin Film Photovoltaic Materials

NSF可持续能源路径(SEP)计划隶属于NSF科学、工程和教育促进可持续发展(SEES)计划，将支持佛罗里达大学的Timothy Anderson教授及同事、宾夕法尼亚州立大学的刘子奎教授及同事、伊利诺伊大学香槟分校的Angus Rockett教授及同事开展的研究计划，以开发富含地球的新型薄膜光伏材料。使用地球上丰富的材料是可持续能源途径所必需的，其中包括大量的光伏发电能力。最近展示的10.1%的电池效率使用富含稀土的Cu2ZnSn(SxSe1-x)4(CZTSe)，将这种吸收材料提升为最有希望的高渗透光伏可持续材料之一。为了支持CZTS的快速发展，需要发展对CZTS材料性能的基础知识。该程序的目的是定义一个自洽的框架，描述CZTSSe系统的热化学和反应动力学。然后，这个框架可以激发智能工艺创新，例如，快速CZTSSe合成路径、定义最佳Se分布的前体结构，或者使整体重组中心最小化的工艺条件。将使用相图计算(CALPHAD)方法来评估文献中的实验数据，并辅之以未知热化学性质的第一性原理计算，以产生对该五组分体系的热力学性质的完整描述。评估还将提供将工艺条件与设备性能联系起来所必需的点缺陷化学成分的洞察。反应路径将通过高温X射线衍射(HTXRD)实验结合材料表征和第一性原理计算来研究，以帮助创建这个地球丰富系统的物种迁移率数据库。可持续光伏的重大采用显然将产生巨大的全球影响。最大的好处归功于10亿人，他们没有可靠的或没有任何电力供应。提出了两个计划，以促进将光伏发电带到这些地区。一位在发展中国家拥有大量发电专业知识的经济学家将进行经济和行为研究，以更好地了解发展中国家光伏发电部署的障碍。除了这项活动外，还将聘请本科生多学科的顶石设计团队，在与光伏制造商合作的同时，定义负担得起的可靠的独立光伏系统。每名博士生将参加我们合作的国家实验室的实习，并邀请一名本科生参与他们的研究。该团队还对新教师的发展感兴趣。一个旨在帮助新教师快速入门的研讨会，目前正向新的和未来的化学工程师教师传授，将适用于化学和材料科学界。归根结底，太阳能是我们能源的主要来源，生产我们的化石燃料、生物质、风能和太阳能热资源，当然，还有使用太阳能电池直接转换的电力。随着我们学习如何大规模制造更高效的太阳能电池板，太阳能电池板的成本正在迅速下降。事实上，每次世界装机容量翻一番，历史电价就下降了22%，现在他们提供的电力低于世界许多地区的零售电力成本。然而，全球太阳能电池板的装机容量只占总产量的很小比例(1%)。面板制造成本主要体现在材料成本和制造工厂建设成本上。在高度部署太阳能电池板的情况下，一些元素的有限供应/高成本将阻止它们的使用。这项研究将重点放在太阳能电池上，使用地球上丰富的铜、锌、锡、硫和可能的硒元素，以确保廉价的材料成本。薄膜太阳能电池的制造速度通常受到吸收光线的化合物形成速度的限制。这个项目的目的是了解如何以非常高的速度制作这些材料。更高的生产率转化为更高的电池产量，从而为制造工厂提供更多的产量。

The NSF Sustainable Energy pathways (SEP) Program, under the umbrella of the NSF Science, Engineering and Education for Sustainability (SEES) initiative, will support the research program of Prof. Timothy Anderson and co-workers at the University of Florida, Prof. Zi-Kui Liu and co-workers at Pennsylvania State University, and Prof. Angus Rockett and co-workers at the University of Illinois at Urbana-Champaign to develop new Earth abundent-based thin film photovoltaic materials. The use of Earth abundent materials is required for a sustainable energy pathway that includes significant photovoltaic (PV) electricity generation capacity. The recent demonstration of a 10.1% efficient cell using earth abundant Cu2ZnSn(SxSe1-x)4 (CZTSe) has elevated this absorber to one of the most promising sustainable material for high penetration PV. Developing a fundamental knowledge of the material properties of CZTS is needed to underpin its rapid development. The aim of this program is to define a self-consistent framework that describes the thermochemistry and reaction kinetics for the CZTSSe system. This framework can then inspire intelligent process innovation, for example, rapid CZTSSe synthesis pathways, precursor structures defining optimal Se distribution, or processing conditions minimizing bulk recombination centers. The CALculation of PHAse Diagram (CALPHAD) approach will be used to assess experimental data in the literature, supplemented by first-principles calculations of unknown thermochemical properties, to produce a full description of the thermodynamic properties of this 5-component system. The assessment will also provide insight into the point defect chemistry necessary to link processing conditions to device performance. Reaction pathways will be investigated using high temperature X-ray diffraction (HTXRD) experiments coupled with materials characterization and first-principles calculations to assist in creating a species mobility database for this earth abundant system. Significant adoption of sustainable PV would clearly have a tremendous global impact. The greatest benefits accrue to the 1 billion people without reliable or any access to electricity. Two programs are proposed to facilitate bringing PV to those areas. An economist with considerable expertise in electricity generation in developing countries will conduct economic and behavioral studies to better understand the barriers to PV deployment in the developing world. This activity will be complemented by engaging undergraduate multidisciplinary capstone design teams to define affordable and reliable individual PV systems, while collaborating with PV manufacturers. Each PhD student will participate in an internship at one of our collaborating national labs as well as engage an undergraduate student in their research. The team also has an interest in new faculty development. A workshop designed to help new faculty start quickly, now being taught to new and prospective chemical engineer faculty, will be adapted for the chemistry and materials science communities. Ultimately, solar energy is the principal source of our energy, producing our fossil fuels, biomass, wind, and solar thermal resources, and of course, electricity by direct conversion using a solar cell. The cost of solar panels is decreasing rapidly as we learn how to manufacture more efficient panels at large scale. Indeed the historical price has decreased 22% every time the installed world capacity doubles, and they are now providing electricity that is less than the retail cost of electricity in many parts of the world. The installed capacity of solar panels world-wide, however, is very small percentage of the total production (1%). The panel manufacturing cost is mainly in the cost of the materials and building the manufacturing plant. At high deployment of solar panels, the limited supply/high cost of some elements will prohibit their use. This research will focus on solar cells using the earth abundant elements copper, zinc, tin, sulfur and a possibly selenium to ensure cheap materials cost. The rate of manufacturing thin film solar cells is normally limited by the rate to form the compound that absorbs the light. This program aims to understand how to make these materials at very high rates. Higher rates translate into higher throughput of cells, and thus more output for a manufacturing plant.