Dr. Madalina Furis
Associate Professor and Materials Science Program Director Physics Department, University of Vermont
January 13th, 12:00 PM
Thirkield Hall (Physics), room 103
Exciton Delocalization and Magnetic Interactions in Crystalline Organic Thin Films
Organic electronics, an interdisciplinary
research area traditionally more connected to organic synthetic
chemistry and polymer science than condensed matter physics, is
currently undergoing a major transformation. The advent of high
mobility small molecule semiconductors and new avenues for scalable
thin film and device fabrication introduce a new paradigm in a research
field that was historically overwhelmingly focused on polymer-based
materials. At the University of Vermont my research group focuses on
exploring excitonic states, low temperature magnetism and
spin-dependent exchange interactions in metal and metal-free octabutoxy
phthalocyanine (OBPc) crystalline semiconducting thin films that belong
to an intermediate regime between a fully localized (Frenkel) and fully
delocalized (Wannier) picture of the excitonic behavior. We employ
condensed matter experimental approaches (in particular low
temperature, polarization-resolved, ultrafast, magneto-spectroscopy) on
a quest for signatures of long range interactions such as exciton
coherence and spin exchange in these systems. Recent results include:
i) the observation of a low temperature coherent exciton state  ii)
the surprising discovery of excitonic states localized at the grain
boundary that may provide new insight on exciton diffusion in these
systems, and iii) the direct observation of an MCD signature of an
exchange between d-shell electrons of the metal ion and the delocalized
π-orbitals of the ligand in transition metal species of MOBPc.
1. Rawat, N., et al. J.Phys. Chem. Lett. 2015, 6(10), 1834-1840.
2. Pan, Z., et al. Nat.Commun. 2015, 6.
3. Rawat, N., et al., Sci. Rep. 2015, 5, 16536.
Email Contact: Madalina.Furis@uvm.edu
Refreshments will be served at 11:50 pm