« Photophysics and BHJ solar cells based on porphyrin and bodipy conjugated polymers »

Pr. Pierre D. HARVEY

Université de Sherbrooke
Faculté des Sciences, Dpt. Chimie
http://laboratoire-pierre-d-harvey.recherche.usherbrooke.ca

Bulk heterojunction (BHJ) solar cells containing small molecules, oligomers and conjugated polymers are still a very active field of research simply because of their cheap processing and that the reported photocurrent efficiencies, PCE, although modest in comparison with inorganic devices, of the newly designed devices are still increasing year after year. Concurrently, the design of so-called “push-pull” molecules and conjugated polymers used in the active layer played one of the determining roles in the recent developments and improvements in BHJ solar cells. Porphyrins and bodipy’s (boron dipyrromethene’s), although known to be extremely common, were not relatively extensively used in comparison with other chromophore species, until now. This lack of past interest for these pigments for the fabrication of BHJ solar cells was probably driven by the relatively poor PCE values for earlier designs. During this same period, photophysical studies of molecular models containing porphyrin and bodipy species covalently attached to various electron acceptors, including fullerene derivatives, appeared in the literature with the about same frequency as designs of new improved BHJ solar cells were reported. These studies provided various information such as the spectral overlap with the solar spectrum and time scales for the basic photophysical events for isolated molecules. This presentation describes the photophysical events (antenna effect; photo-induced and back electron transfer) occurring in models and in BHJ solar cells, along with the design of BHJ solar cells exhibiting record high PCE’s for “push-pull” oligomers and polymers containing these dyes. Comments about morphology improvement (i.e. thermal annealing, solvent vapour annealing, and addition of solvent) leading to increased PCE’s will also be made.

« Co(II) based Single ion Magnets and en amazing MOF based Sensor »

Pr. Sanjit KONAR

Department of Chemistry
Indian Institute of Science Education & Research Bhopal, India
https://chm.iiserb.ac.in/faculty_skonar.php

The smallest magnet-like molecules containing only one single magnetic ion usually called single-ion magnet (SIM). The development of this class of molecules, i.e., SIMs, are currently the hottest topics in SMM research and the reason for which is their simple structure compared with polynuclear complexes that allows to have a better understanding of the correlation between structures and magnetic properties. In most of the reported transition metal-based SIMs, one common feature is the low coordination number of the metal centers as the single ion anisotropy is enriched due to the unrestricted orbital angular momentum by limiting the coordination number of the metal ion. The efforts to rationally control the single ion anisotropy have been escalated during the last few years. Many mononuclear tetra-coordinated, penta-coordinated, hepta-coordinated CoII SMMs have been reported with varieties of geometries. However, factors regulating single ion anisotropy are not well comprehended and intricate control over magnetic anisotropy is one of the most challenging tasks. An elaborative experimental and computational study will be discussed on selected example of Co(II) based SIMs to shed light in the effect of coordination environment and geometry on magnetic anisotropy of these complexes.1-2
In the second part of my talk, a novel Cu(I) based two-dimensional metal-organic framework (MOF)3-4 will be presented. The MOF is found to behave as a colorimetric detector for the widest variety of small molecules like different solvents, halobenzenes, N-heterocycles, amine and nitroaromatic explosives all in vapor phase through a Single Crystal to Single Crystal (SCSC) transformation. Notably, till date, this is the only report of a material that encapsulates such a large number of small molecules in the vapor phase in SC-SC fashion with visible color changes.

References
1.   Mondal, A. K.  Jover, J. Ruiz, E. Konar, S. Chem.Comm., 2017, 5338-5342.
2.   Mondal, A. K. Jover, J. Ruiz E. Konar, S. Chem. A Eur. J., 2017, 51, 12550-12558
3.   Khatua S., Goswami S.,  Biswas S., Tomar K., Jena H. S.,  Konar S., Chem. Mat., 2015, 27,
5349-5360.
4.   Khatua, S., Bar, A. K., Sheikh, J. A., Clearfield, A., Konar, S., Chemistry- A European
Journal, 2017, 24, 872 –880

SEMINAIRE COMMUN IPCMS / CESQ  (Centre Européen de Sciences Quantiques) / EUR QMAT

« Quantum simulation with light: from superfluidity to rotating black holes »

Quentin GLORIEUX

Maitre de Conférences Sorbonne Université
Laboratoire Kastler Brossel (LKB)
Ecole Normale Supérieure – Sorbonne Université – CNRS
Membre Junior de l’IUF

During this presentation I will introduce the basics of hydrodynamics with light in two important systems: exciton-polariton micro-cavities and warm rubidium vapors. Using the analogy between the non-linear Schrodinger equation and the Gross-Pitaevskii equation, I will answer the question about “Can we observe superfluidity with light ?”
I will also discuss recent non-linear and quantum optics experiments through the perspective of hydrodynamics and I will show what are the surprising consequences of this approach.
Finally, I will review recent attempts to observe an analogue of the Hawking radiation at a black hole horizon with table-top experiments.

« Spin Crossover Particles: Exploring New Processes for the Synthesis of Nanoparticles and Nanocomposites »

Dr. Guillaume CHASTANET

Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB)

Affiche-Abstract

« Levitated Nanophotonics »

Lukas NOVOTNY

ETH Zurich, Photonics Laboratory, 8093 Zurich, Switzerland

Affiche – Abstract