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Place Amphi Dorothy Hodgkin
Title:
Photoswitchable fluorescence hysteresis based on multichromophoric architectures
Resume:
The Laboratory of Supramolecular and Macromolecular Photophysics and Photochemistry (PPSM, CNRS UMR 8531), located at École Normale Supérieure Paris-Saclay (Cachan) has a well-established experience in the field of synthesis and spectroscopy of multifunctional photo-active molecules. In the frame of a research project funded by the French National Research Agency (ANR), the PPSM offers a PhD fellowship to design photochromic-fluorescent dendrimeric molecules, showing switchable fluorescence hysteresis induced by light. In the field of smart materials, photoswitchable multichromophoric systems are prone to show fluorescence hysteresis effects, unexplored to date. The PhD project proposes to design well-structured molecular architectures composed of a large number of fluorescent and photochromic units linked to a cyclodextrin platform, allowing energy transfer processes. The competitive photoisomerization kinetics of the different photo active units are expected to drive the system to different reaction pathways when illuminated by UV or visible light, leading to a fluorescence hysteresis cycle. A multidisciplinary approach, combining molecular design, synthetic chemistry and spectroscopy, is expected to tackle this challenging topic. Such a hysteresis behavior originates from collective effects and interactions between molecular subunits. It is of great fundamental interest, but also promising for the development of a wide variety of high-technology devices. Consequently, the scientific target of the PhD work will be devoted to the following aspects: Design and synthesis of the fluorescent and photochromic molecules: individual chromophoric units, small dendric scaffolds and cyclodextrin-based architectures bearing different numbers of photochromes and fluorophores Steady-state and time-resolved photophysical investigations of the multichromophoric assemblies, in order to rationalize the structure-properti es relationships, and demonstrate the photoswitchable fluorescence hysteresis The fluorescence hysteresis developed by the PhD project is expected to lead to a new generation of intelligent molecular materials. Photo-controllable and multi-dimensional optical devices can be developed, such as information encoders, logic gates, non-volatile optical memories or security systems, but also smart (or furtive) fluorescent probes for bioimaging. Applicants must be well-experienced in organic synthesis and standard characterization techniques. Some practice of molecular spectroscopy (UV-vis, fluorescence), would be appreciated.
This work is available online.