Materials World Network: Intermediate Band Semiconductor Materials for High Efficiency Solar Energy Conversion

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

This Materials World Network focuses on efficient solar energy conversion via intermediate electronic states in II-VI-O compound semiconductors in collaboration between researchers at The University of Michigan (US) and the Instituto de Energia Solar at the Universidad Politécnica de Madrid (Spain). Intermediate states in the bandgap of a semiconductor material provide multiple optical transitions and corresponding optical absorption bands. Solar cell devices based on these materials offer a potential route to high efficiency using a material with three defined absorption bands in a simplified one-junction structure. The introduction of oxygen isoelectronic impurities in II-VI compound semiconductors show promise in realizing optical transitions with high radiative efficiency and energetic positions well matched to the solar spectrum. While these materials are well suited for highly efficient solar energy conversion, major advances in material synthesis and the understanding of optoelectronic properties are required. The primary technical objectives of this project are 1) the theoretical and experimental study of oxygen states in II-VI materials, 2) characterization of multi-photon optical transitions in II-VI-O materials, and 3) determination of charge carrier transport in via intermediate electron states. Research on intermediate band materials will directly impact photovoltaic solar cell technology, where the projected high efficiency and simplistic single-junction device design would lower the cost of solar energy conversion. This project will contribute to the education of graduate students by funding research abroad, exchange of scientists, and the establishment of a seminar series. The partnership will also enhance existing educational efforts at the University of Michigan, where freshman in the Engineering 100 course on photovoltaics and solar-powered systems will have a connection to a leading solar energy institute as a part of their team project to design and implement a system powered by solar energy. This project is jointly funded by Division of Materials Research (DMR) and the NSF Office of International Science and Engineering (OISE).