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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 [1] ii) the surprising discovery of excitonic states localized at the grain boundary that may provide new insight on exciton diffusion in these systems,[2] 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.[3]

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