UB - University at Buffalo, The State University of New York Chemical and Biological Engineering

Organic solar cells: Characterization of interfacial charge-separation and charge-recombination processes

September 20, 2017

Jean-Luc Bredas

Georgia Tech

In this presentation, we will first introduce the working principles of organic solar cells and rationalize the need for the presence of both an electron-donor component (usually a conjugated polymer or oligomer) and an electron-acceptor component (often a fullerene derivative).
We will then discuss the impact that inter-molecular arrangements and interactions at the donor/acceptor (polymer/fullerene) interfaces have on the performance of bulk-heterojunction solar cells. We will describe the results of combined electronic-structure calculations and molecular-dynamics simulations. In particular, we will examine:
(i) the propensity of fullerene molecules to dock preferentially on top of the electron-poor moiety or electron-rich moiety of the polymer, as a function of the nature and location of the polymer side chains;
(ii) the impact that the packing arrangements have on the energetic distribution of the charge-transfer interfacial electronic states and their localization/ delocalization characteristics; and
(iii) the influence of molecular packing and electronic delocalization on non-radiative recombination processes.
We will end with a discussion of the prospects of the field of organic solar cells.

This work is supported by ONR (Award N00014-14-1-0580 for the Center for Advanced Organic Photovoltaics and Award N00014-17-1-2208).

Bio Sketch

Jean-Luc Bredas received his Ph.D. from the University of Namur, Belgium, in 1979. In 1988, he was appointed Professor at the University of Mons, Belgium, where he established the Laboratory for Chemistry of Novel Materials. While keeping an ?Extraordinary Professorship? appointment in Mons, he joined the University of Arizona in 1999 before moving in 2003 to the Georgia Institute of Technology. At Georgia Tech, he is Regents? Professor of Chemistry and Biochemistry and holds the Vasser-Woolley and Georgia Research Alliance Chair in Molecular Design. Between 2014 and 2016, he was on a leave of absence at King Abdullah University of Science and Technology (KAUST), where he served as Distinguished Professor of Materials Science and Engineering and Director of the KAUST Solar Center before resuming his activities at Georgia Tech in 2017. His research interests focus on the computational characterization and design of novel organic materials for organic electronics and photonics.
Jean-Luc Bredas is a Member of the International Academy of Quantum Molecular Science, the Royal Academy of Belgium, and the European Academy of Sciences where he serves as Officer of the Engineering Division. He is the recipient of the 1997 Francqui Prize, the 2000 Quinquennial Prize of the Belgian National Science Foundation, the 2001 Italgas Prize, the 2003 Descartes Prize of the European Union, the 2010 Charles H. Stone Award of the American Chemical Society, the 2013 David Adler Award in Materials Physics of the American Physical Society, and the 2016 Award in the Chemistry of Materials of the American Chemical Society. He is a Fellow of the American Chemical Society, American Physical Society, Optical Society of America, Royal Society of Chemistry, and Materials Research Society, and an Honorary Professor of the Institute of Chemistry of the Chinese Academy of Sciences. He holds honorary degrees from the University of Linköping, Sweden, and the Free University of Brussels. He has published over 1,000 refereed articles (that have garnered some 70,000 citations, leading to a current Web of Science h-index of 118) and given over 500 invited presentations. Since 2008, he has served as Editor for ?Chemistry of Materials?, published by the American Chemical Society.

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