Small Molecule Squaraine Donor Materials in Bulk Heterojunction Organic Solar Cells

Susan Spencer, PhD Candidate in Microsystems Engineering, Rochester Institute of Technology Rochester, New York

The Collison Group focuses research efforts on developing novel squaraine materials for use in solution-processed single junction organic solar cells.  By changing the molecular structure of the squaraine, we can change its fundamental properties of absorption, aggregation, and crystallinity, all of which impact the efficiency of the solar cell.. Our goal is to improve the efficiency through prescriptive description of molecular structure of materials, which requires us to take advantage of squaraines’ unique properties in determining improved mechanistic understanding of the solar cells. This talk will focus on recent results demonstrating efficiencies of >4% and how those results can be explained with both theory and experiment. The characterization of the materials will be briefly described, and a short discussion of excitonic theory will be given as it relates to the presence of H- and J-aggregates within the photovoltaic. The proposed impact of these aggregates on the process of charge photogeneration will be presented, including a discussion of the application of Marcus-Hush theory to the crucial step of exciton dissociation at the bulk heterojunction. Current and future experiments will be highlighted, with a focus on the blending of experiment, computational modeling, and theory that drives the research of the group.

Cette conférence est présentée par le RQMP Versant Nord du Département de physique de l'Université de Montréal et le Département de génie physique de Polytechnique Montréal.