| 09:00 |
|
| 10:00 |
|
| 11:00 |
|
| 12:00 |
|
| 13:00 |
|
| 14:00 |
|
| 15:00 |
|
| 16:00 |
[16:00] MST Colloquium
- 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.
|
| 17:00 |
|
| 18:00 |
|
| 19:00 |
|
| 20:00 |
|
| 21:00 |
|
May 2016
