SusChEM: Collaborative Research: Novel Nanostructured Metal Oxides for Efficient Solar Energy Conversion - Theory, Synthesis, and Interfacial Carrier Dynamics

非技术描述：金属氧化物材料可以为薄膜太阳能电池中现有的光吸收材料提供地球丰富的无毒替代品。然而，基于现有金属氧化物的太阳能电池的效率通常由于差的材料性质而低。在该项目中，伍斯特理工学院（WPI）和德克萨斯大学阿灵顿分校（UTA）的研究人员正在通过理论预测和实验合成具有新成分和增强性能的金属氧化物材料来提高金属氧化物的效率。此外，通过在纳米级上构造这些材料来提高效率。这些工作由太赫兹光谱测量指导，用于了解材料成分，纳米结构和效率之间的关系。这个SusChEM项目的预期成果是开发可持续薄膜太阳能电池的基本新知识，该电池由能够以实际效率进行太阳能转换的金属氧化物组成。该项目涉及研究生和本科生研究人员的培训和参与。此外，WPI的研究人员正在为来自当地地区的中学女生和高中教师开发和提供关于光化学和纳米技术的讲习班和教学模块，这些地区为大量低收入，少数民族和代表性不足的学生提供服务。UTA的研究人员通过交互式计算机实验室为非洲裔美国人和西班牙裔高中生提供服务。技术描述：这项SusChEM研究的目标是显着提高多金属氧化物的太阳能转换效率，这可以为现有的薄膜材料（如CIGS和CdTe）提供地球丰富的无毒替代品。金属氧化物通常具有大的带隙或差的电荷迁移率，或两者兼而有之，这限制了它们的太阳能发电效率。该项目通过三种协同方法处理这些问题：i）理论上预测和合成用于太阳能转换的具有改进的带隙和更高的电荷迁移率的多金属氧化物的新合金，ii）将这些新氧化物的薄层涂覆到阵列集电器上以提高它们的效率，以及iii）使用太赫兹光谱来研究这些纳米结构氧化物中的体载流子动力学和界面电荷转移，并进一步提高效率。这种多管齐下的方法是第一个i）研究新的多金属氧化物合金，其通过合金化对能带工程有很大的希望，同时仍然实现相对高的迁移率，ii）同时应用“极薄吸收体”纳米结构化和界面工程策略以提高多金属氧化物吸收体的电荷收集效率，以及研究纳米结构集流体上薄金属氧化物吸收体中的超快载流子动力学，重点关注体载流子动力学和吸收体/集流体界面处的电荷提取。

Non-technical Description: Metal oxide materials could offer earth-abundant, non-toxic alternatives to existing light-absorber materials in thin-film solar cells. However, efficiency of solar cells based on existing metal oxides is typically low due to poor material properties. In this project, researchers at the Worcester Polytechnic Institute (WPI) and the University of Texas at Arlington (UTA) are working on increasing the efficiency of metal oxides by theoretically predicting and experimentally synthesizing metal oxide materials with new compositions and enhanced properties. In addition, efficiency is enhanced by structuring these materials on the nanoscale level. These efforts are guided by terahertz spectroscopy measurements, which are used to understand relationships between the material composition, nanoscale structure and efficiency. The expected outcome of this SusChEM project is essential new knowledge for the development of sustainable thin-film solar cells composed of metal oxides capable of solar energy conversion with practical efficiencies. The project involves training and participation of graduate and undergraduate researchers. In addition, the WPI researchers are developing and delivering workshops and teaching modules on photovoltaics and nanotechnology for middle school girls and high school teachers from local districts serving large populations of low-income, minority and underrepresented students. The UTA researchers are serving African-American and Hispanic high-school students through interactive computer labs.Technical Description: The objective of this SusChEM research is to significantly improve solar energy conversion efficiencies in multi-metal oxides, which could offer earth-abundant, non-toxic alternatives to existing thin-film materials such as CIGS and CdTe. Metal oxides typically suffer from large band gaps or poor charge mobilities, or both, which has thus far restricted their solar-electricity efficiency. This project tackles these issues via three synergistic approaches: i) theoretically predicting and synthesizing new alloys of multi-metal oxides with improved band gaps and higher charge mobilities for solar energy conversion, ii) coating thin layers of these new oxides onto nanowire-array current-collectors to enhance their efficiency and iii) using terahertz spectroscopy to study the bulk carrier dynamics and interfacial charge transfer in these nanostructured oxides and further improve efficiency. This multi-pronged approach is the first to i) investigate new multi-metal oxide alloys that hold much promise for band engineering via alloying while still achieving relatively high mobility, ii) simultaneously apply 'extremely-thin-absorber' nanostructuring and interfacial engineering strategies to improve the charge collection efficiency of multi-metal oxide absorbers and iii) study the ultrafast carrier dynamics in thin metal oxide absorbers on a nanostructured current-collector, focusing on both bulk carrier dynamics and charge extraction at the absorber/current-collector interface.