Measuring Microscopic Charge Exchange in Heterogeneous Organic Thin Films

In this award, funded by the Chemical Structure, Dynamics and Mechanisms (CSDM-A) Program of the Division of Chemistry, Professor Aaron Massari of the University of Minnesota and his graduate and undergraduate student colleagues are investigating the ways that microscopic heterogeneity influence the physical properties in molecular electronic materials. Prof. Massari's research uses sophisticated spectroscopic techniques to measure the molecular dynamics in materials while they are being electrically driven. The ultimate goal of research like this is to develop better electronic materials. Students working in the Massari group receive training in ultrafast laser techniques and in cutting-edge spectroscopic and optical methods. The Massari group also conducts educational outreach trips to do hands-on chemistry activities with large numbers of students and teachers from rural, geographically-isolated parts of Minnesota, through the University of the Prairie program at the University of Minnesota Southwest Regional Outreach Center.

Prof. Aaron Massari and his research group conduct a series of experiments to probe the ways in which molecular-scale heterogeneity in molecular electronic materials impacts performance. Specifically, Massari and his group use two-dimensional infrared spectroscopy to probe short-range charge exchange in materials with variable amounts of heterogeneity. Specific molecular systems to be studied include a number of ruthenium-based dyes (N3, Z907, etc.) as well as some indoline-based dyes (D102, D149, etc.) p-doped with iodine. Additional experiments use organic p-dopants. Experiments are combined with MD simulations to help with the modeling/analysis. The specific goals of the research include: (1) measuring and modeling the site-to-site carrier exchange in thin molecular films; (2) identifying the role of molecular aggregation on charge transport in both dye systems, and (3) investigating the influence of the nature of p-type dopants on the charge transport phenomenon. The Massari research group includes active involvement by a diverse group of undergraduates in research, including students from groups underrepresented in the sciences.