CAREER: Very High Efficiency Organic-Based Photovoltaic Cells - Novel Nanostructure and Photon, Exciton, and Electron Management

University Of Florida, Gainesville FL

Investigators

Abstract

Background: Finding sufficient supplies of clean energy to replace the depleting and polluting fossil fuels will be one of society's foremost challenges for the next half-century. Solar energy is clean, abundant and renewable, yet it is vastly under-utilized in the current world. One major solar energy utilization approach is the direct conversion of sunlight to electricity using photovoltaic cells; however this has only constituted a negligible portion of the overall energy supply, mainly due to the high manufacturing and installation costs of photovoltaic modules. Devices based on organic materials can potentially provide very low cost solar energy conversion due to their low material cost, ease of processing, and compatibility with flexible substrates. There have been considerable interests in organic-based photovoltaic (OPV) cells in the last two decades, and the power conversion efficiency of OPV cells has steadily improved to the current record of approximately 5%. However, not only such efficiencies are still far lower than the theoretical limits, but it is imperative to greatly improve the efficiency to really make this technology suitable for future large-scale commercial applications. Intellectual Merit: This CAREER proposal focuses on developing very high efficiency, organic-based photovoltaic cells, which have the potential to provide low cost solar energy conversion due to many technological advantages of organic electronic materials. Utilizing his knowledge and expertise in device physics, device fabrication, material processing, and characterization, the PI will address several fundamental device issues in organic photovoltaic cells by employing novel nanostructures and approaches to manage the photons, excitons, and electrons. The goal is to thrust the power conversion efficiency of these devices from the current 5% mark to the 15-20% regime. The research activities of this program consist of four components: controlled fabrication of an interdigitated nanostructured donor-acceptor heterojunction conducive to very efficient exciton dissociation and charge transport; study of the mechanisms contributing to the dark current and the energetics at the material interface to increase the voltage output; harvest of near-infrared photons with low-gap organic materials and inorganic nanocrystals; and application of the host/guest system to achieve long exciton diffusion lengths without sacrificing the coverage of the solar spectrum. Broader Impacts: This program addresses fundamental engineering science research with strong technological relevance to the electronics/photonics. In particular, direct conversion of solar energy to electricity using low-cost, high efficiency organic-based photovoltaic cells will have a tremendous socio-economical impact on the world's energy supply. Moreover, the PI is committed to closely integrate research and education, and to promote student's involvement at all levels. A strategic educational program has been designed to include student training, curriculum contribution, and outreach to K-12 students and teachers. The PI will also work with the local utility company to educate and outreach to the general public.