MSE Seminar - Dr. Garry Rumbles - NREL
Title: The Science and Future Direction of Organic Photovoltaic Solar Cells
The past 25 years have seen a flurry of research activity in the development of organic photovoltaic (OPV) solar cells, with solar power conversion efficiencies increasing from just a few percent to now exceeding 10%. Over the same time period, many OPV-related companies have come and gone and now is a good time to take stock of the situation. This presentation will present a brief overview of this 25-year pathway, exploring what we have learned, what we still struggle to understand, and how can we progress further.
In addition, we will investigate some key scientific questions that remain in the field of OPV solar cells, such as: how do charges get generated, where are they generated, and how do they successfully emerge from devices? Specifically, this presentation will focus on the use of the novel spectroscopic technique of time-resolved microwave conductivity (TRMC) to investigate the production and loss of free, mobile charges in a number of organic systems that are often found in OPV devices. These systems are comprised of light-harvesting conjugated polymers blended, or mixed, with a variety of high electron affinity acceptor molecules, such as novel substituted fullerenes and phthalocyanines. We will explore the role of the solid-state microstructure of the polymer, the energetics of the acceptor molecules, and where these molecules might reside within the polymer microstructure. To break slightly with tradition from the OPV field, a molecular or chemical approach of a Marcus formulation will be used to explain the fundamental, charge-generating process.
Dr. Garry Rumbles is a Research Fellow at the National Renewable Energy Laboratory (NREL), a Professor Adjoint in the Department of Chemistry and Biochemistry at CU Boulder, a Fellow of the joint CU/NREL adventure Renewable and Sustainable Energy Institute (RASEI), and an Affiliated Faculty in the Department of Chemistry at Colorado State University. In addition, he is a Visiting Professor in the Nanostructured Materials and Devices Group in the Department of Chemistry at Imperial College, London. Dr. Rumbles’ research program focuses on the fundamental science of solar energy conversion in organic and hybrid structures, with emphasis on the factors that influence the generation of free-charge carriers in systems that contain conjugated polymers as the primary light-harvester. He obtained his BSc in Chemistry with Electronics from the University of Southampton (1980) and his PhD from the University of London (1984) working under the supervision of Professor David Phillips at the Davy Faraday Research Laboratory, The Royal Institution, London. Prior to joining NREL he was a member of faculty in the chemistry department at Imperial College, London.
Host: David Bucknall
Reception at 3:30 preceeding seminar outside Boggs B6