| Login |
| Description: | Monday, May 30, 2016 Speaker: Madalina Ioanna Furis Affiliation: Department of Physics, University of Vermont Title: Exciton Delocalization and Magnetic Interactions in Crystalline Organic Thin Films Location: Computer Science Department, room A115-A117 (ground floor), Voutes Time: 16:00 Language: English Abstract 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 octabutoxyphthalocyanine (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-phonon coupling and spin exchange in these systems. Recent results include: i) the observation of a low temperature nominally “dark” exciton state that is now optically-allowed because intermolecular interactions led to a breakdown of the selection rules,[1] ii) the surprising discovery of excitonic states localized at the grain boundary that provides 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. |
| Location: | Computer Science Department, room A115-A117 (ground floor), Voutes |
| Status: | Waiting for approval |
| Date: | Monday, May 30, 2016 |
| Time: | 16:00 EEST |
| Priority: | 5-Medium |
| Access: | Public |
| Created by: | Lila Kalogeraki |
| Updated: | Thursday, May 26, 2016 10:58 GMT |