Catégorie : Non classé

Our article is available to read at J. Phys. Chem. C.

In the present work, two viologen derivatives were synthesized and used in molecular junctions (MJs) to investigate the impact of a decoupling unit on the rectification behavior. Both bear an aniline terminal unit but one of the viologen derivative (named VIO-C₁) is terminated by a methyl group whereas the other (named VIO-C₆) bears a six-carbon (C₆H₁₃) terminal chain. Thin layers of each derivative were deposited on gold microelectrodes by the electroreduction of the corresponding diazonium reagents, and solid-state MJs were fabricated to study the electronic transport. JV curves of VIO-C₁ show a symmetric behavior, whereas the VIO-C₆ (with alkyl chain) JV curves show strong asymmetry in the transport. This behavior is attributed to the decrease of the electronic coupling at the top interface due to the alkyl chain and is confirmed by comparison with similar VIO-C₁ MJs in which a thin AlO_x layer is inserted on top of the VIO-C₁ layer. The impact of this decoupling unit on the rectification ratio is discussed.

Our article is available to read at J. Mater. Chem. C.

Naphthalenediimide amphiphiles (NDI-as) with quaternary ammonium groups (DC4, DaP, and DaO) display unprecedented UV light-induced aggregation in solutions of water, acetonitrile and THF. Light-induced aggregation brings significant spectral modification by which unusual absorption band distribution is assigned to H-type aggregates. Such aggregation can be reversibly broken by heating and reassembled by photoirradiation. The irradiation/heating cycles that provoke assembly/disassembly process can be confirmed by ¹H-NMR spectroscopy. The possibility of a chemically promoted aggregation by or radical anion either anion–π interaction may be ruled out by UV-Vis, EPR and electrochemistry measurements. These photoinduced aggregates can sensitize dissolved O₂ to produce singlet oxygen, a surprising observation when it comes to sensitization efficiency for dyes as aggregation usually decreases sensitization yield. Laser-induced luminescence measurements corroborate the existence of monomeric and aggregate forms, as well as confirm triplet states as phosphorescence was detected, being particularly intense in concentrated THF solutions.

Ambition Internationale (2024-2026)

“On-surface chiroptical properties in self-assembled monolayers for photonics and optoelectronics”

Partners involved :
P1 : UMR 5182 – Laboratoire de Chimie, ENS Lyon (Coord. D. Frath)
P2 : UMR 5306 – ILM, Université Claude Bernard Lyon 1 (S. Guy)
P3 : Nara Institute of Science and Technology (T. Kawai)
P4 : Graduate School of Engineering, Kyoto University (K. Matsuda)

After a MSc degree at INSA Rouen, I moved to University of Strasbourg for a PhD supported by a MENRT fellowship. My doctoral work was focused on the light driven production of hydrogen and on the synthesis of novel fluorescent dyes. Then I worked on STM analyses of photoresponsive self-assembled monolayers as a JSPS fellow at Kyoto University, on redox-active molecular layers for electronic devices at Paris Diderot University and binuclear phthalocyanine metallic complexes for catalytic reactions at CNRS in Lyon. I am currently working as CNRS research associate at the Chemistry Laboratory of ENS Lyon.

My research interests are directed towards π‐conjugated molecules with optical and electrochemical properties, their supramolecular self-assembly and functional materials with switchable properties (gels, liquid crystals, surfaces…).