Theoretical Characterization of Donor/Acceptor Interfaces in Organic Solar CellsPrincipal Investigator: Jean-Luc Brédas
The computational work in the Bredas group focuses on the theoretical description of the electronic and optical properties of π-conjugated materials. These compounds play a critical role in the development of new generations of organics-based devices such as organic light-emitting diodes for displays or solid-state lighting, ﬁeld-effect transistors, and solar cells. Organic photovoltaics offers the potential of using solar energy to produce electricity from low-cost, ﬂexible devices. However, the efﬁciency of all-organic solid-state solar cells remains low (at best ∼5-6% power conversion efﬁciency) and has to increase signiﬁcantly for the technology to enter the market place. A better understanding of the electronic and optical processes taking place in an organic solar cell can help in designing more efﬁcient materials.
We seek to provide a detailed theoretical characterization of organic/organic donor/acceptor (D/A) interfaces in organic solar cells, in terms of: the electronic structure of the ground and excited electronic states; the polarization effects due to the inhomogeneous nature of the surrounding medium at the interface; and the role of interfacial molecular packing and of the intra- and inter-molecular geometry relaxations upon excitation. The goal is to accurately determine the electronic structure of complexes consisting of donor and acceptor molecules in the ground state, in the excited states, and in the charged states.