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丰富的、无毒的替代品。然而，基于现有金属氧化物的太阳能电池由于材料性能差，效率通常较低。在这个项目中，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，通过在纳米尺度上构建这些材料，效率得到了提高。这些工作是在太赫兹光谱测量的指导下进行的，太赫兹光谱测量用于了解材料成分、纳米级结构和效率之间的关系。SusChEM项目的预期成果是开发可持续薄膜太阳能电池的重要新知识，该电池由金属氧化物组成，能够以实际效率进行太阳能转换。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的研究人员正在为为大量低收入、少数民族和代表性不足的学生服务的当地地区的初中女生和高中教师开发和提供关于光伏和纳米技术的讲习班和教学模块。犹他大学的研究人员通过交互式计算机实验室为非洲裔和西班牙裔高中生提供服务。技术描述：这项SusChEM研究的目标是显著提高多金属氧化物中的太阳能转换效率，这可以为现有的薄膜材料（如CIGS和CdTe）提供丰富的、无毒的替代品。金属氧化物通常存在较大的带隙或电荷流动性差，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解决这些问题：1)从理论上预测和合成具有改善带隙和更高电荷迁移率的新型多金属氧化物合金，用于太阳能转换；2)将这些新氧化物薄层涂覆在纳米线阵列集流器上，以提高其效率；3)利用太赫兹光谱研究这些纳米结构氧化物中的散体载流子动力学和界面电荷转移，进一步提高效率。这种多管齐下的方法是第一个：1)研究新的多金属氧化物合金，这种合金在通过合金化进行能带工程的同时仍能实现相对较高的迁移率；2)同时应用“极薄吸收剂”纳米结构和界面工程策略来提高多金属氧化物吸收剂的电荷收集效率；3)研究纳米结构集流器上薄金属氧化物吸收剂中的超快载流子动力学。重点研究散体载体动力学和吸收器/集流器界面的电荷提取。

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.