DSI Seminar presented by Gracie Chaney

Gracie Chaney (Sorbonne Université, Laboratoire de Chimie Theorique PARIS)

Abstract : Although ab initio molecular dynamics (AIMD) can predict the chemical reactions in materials with quantum accuracy, it suffers from computational inefficiency that constrains simulations in size (<1000 atoms) and time (<100 ps). Machine learned interatomic potentials (MLIPs) bridge the gap between quantum accuracy and classical efficiency by learning the potential energy surface of the system from the AIMD data and using it as the force field in classical molecular dynamics (CMD) simulations. In this presentation, I will feature two very different systems for which I have used MLIPS. The first is the interface of a solid-state battery consisting of a Li-metal anode and an argyrodyte Li6PS5Cl solid-state electrolyte. By using a moment-tensor potential scheme we were able to generate an MLIP that accurately predicted the short- and long-term growth of the solid-electrolyte interphase region initiated by reduction of the electrolyte by the anodic Li [2]. The second system consists of a dense liquid of NH3/H2O/CH4 subjected to extreme temperatures (3000 K) and pressures (22-69GPa). In this case, we used an equivariant neural network potential [3] trained on an even distribution of NH3/H2O/CH4 structures of various NH3 amounts (4, 8, and 12). Both the AIMD and MLIP+MD simulations showed that increasing pressure at high temperature induces water ionization and begins a process involving the formation of transient CH5+ molecules and highly reactive carbocations that drive hydrocarbon chain growth toward nanodiamonds. Such results could be useful for understanding the dynamics within icy giant planets, such as Uranus and Neptune.

[1] Ivan S Novikov et al. 2021 Mach. Learn.: Sci. Technol. 2, 025002

[2] Gracie Chaney et al. 2024 ACS Appl. Mater. Interfaces 16, 19, 24624–24630

[3] Musaelian, A., Batzner, S., Johansson, A. et al. (2023) Nat Commun 14, 579

Contactc : Hervé Bulou (0388107095 – herve.bulou@ipcms.unistra.fr) et Christine Goyhenex (0388107097 – christine.goyhenex@ipcms.unistra.fr)

Seminar : Joël Bellessa

Joël Bellessa (Institut Lumière Matière, CNRS-Université Lyon 1)

The proximity of nanostructures or metallic films to semiconductors significantly affects their properties, particularly optical ones. First, we will describe the strong light–matter coupling between organic semiconductors (J-aggregate molecules) and a surface plasmon mode. We will specifically discuss the collective effects between different molecules induced by light–matter hybridization. By structuring the material on the scale of the coherent mode extension, we will show that it is possible to create an original type of active polaritonic metasurface, as well as to achieve efficient energy transfer. In a second part, we will address structures composed of metals and inorganic semiconductors (gallium arsenide). The potential applications of these structures for the realization of surface lasers will be described.

Seminar : Prof. Ryo Nakayama

Speaker : Prof Ryo Nakayama, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan

Abstract :

Thin-film model systems offer a powerful platform for studying interfacial phenomena in solid-state lithium batteries and complex hydride electrolytes.  At the Li₃PO₄/LiCo₀.₅Mn₁.₅O₄ interface in a thin-film lithium batteries, the resistance increases above 5 V vs Li/Li+ due to interfacial layer formation but relaxes over time, indicating reversible behavior.  Epitaxial NaBH₄ thin films have been successfully fabricated via infrared pulsed-laser deposition, allowing control over growth orientation which is useful for interface study. These findings highlight the effectiveness of thin films in elucidating interface properties and advancing solid-state energy materials.

Contact: Pierre RABU : pierre.rabu@ipcms.unistra.fr

Seminar from Pr. Chihaya Adachi, CNRS fellow-ambassador

Speaker : Prof. Chihaya Adachi

Chihaya Adachi is a professor at Kyushu University in Japan and director of the Photonics and Organic Electronics Research Centre (OPERA). His activities focus on the chemistry, physics and implementation of organic semiconductor materials for applications in photonics and organic electronics. In particular, it is behind the development of the third generation of light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) organic materials. Cultivating close links with industry, Chihaya Adachi has co-founded two start-ups: Kyulux, in 2014, for the development and commercialisation of new materials for the OLED market; and Koala Tech, in 2019, for the development of purely organic laser materials and devices. Finally, he has developed numerous international collaborations, particularly with France. In 2023, the CNRS launched the IRP LUX-ERIT, which brings together the OPERA laboratory and four French laboratories, including the Institut de Physique et de Chimie des Matériaux de Strasbourg (IPCMS), the Institut Lavoisier de Versailles (ILV), the Laboratoire de Physique des Lasers (LPL) and the Institut Parisien de Chimie Moléculaire (IPCM), which is currently coordinating the project on the French side.

To meet C. Adachi, please contact: stephane.mery@ipcms.unistra.fr

DMO Seminar presented by : Olivier MAURY

Olivier Maury (ENS, https://perso.ens-lyon.fr/olivier.maury/)

Old polymethine dyes, discovered in the middle of the XIXth century for photography application, continue to hold a real fascination in the scientific community owing to their unique spectroscopic properties. In the last decade, these dyes found a renewal of interest for near-infrared (NIR) applications in biological imaging or for the design of advanced photonic materials (laser dyes, nonlinear optics…). Generally speaking, polymethine dyes are charged compounds where the positive (resp. negative) charge is delocalized between two electron-donating (resp. withdrawing) groups via an odd number of sp2 carbon atoms. In spite of their wide range of use, the complete rationalization of their very particular photophysical properties remains a matter of debate from both experimental and theoretical points of view. 

Quantum sciences and materials seminar prensented by : Alexina Ollier

Speaker: Alexina Ollier, Center for Quantum Nanoscience (QNS), Institute for Basic Science (IBS), Seoul, South Korea

Here, we report on imaging the spin texture of triple-Q magnetic order of Co1/3TaS2. The sample
was measured with a low temperature STM (T=6K) under ultra-high vacuum with normal
and spin-polarized tips. The STM images with the normal tip show the triangular lattice of the
sample. The spin-polarized (SP) tip shows an additional symmetry related to the triple-Q
ordering. In addition to that, the SP STM images revealed different spin textures with respect
to the tip-spin orientation. The analysis suggests the presence of a phase difference between the
tip and the triple-Q ordering of the sample. This work gives a new insight into the exploration of
chiral magnetic ordering with topological Hall effect using scanning probe microscopy.

Seminar Axis 2 presented by : Thomas PONS

Thomas PONS (Laboratoire de Physique et d’Etudes des Matériaux, ESPCI, Sorbonne Université, Paris (LPME))

Fluorescent biodetection assays using pairs of fluorescent donors and acceptors interacting via Förster Resonant Energy Transfer (FRET) are appealing thanks to their ease of use, versatility and specificity. They are however limited in sensitivity due in particular to their limited distance range. We are currently developing a novel type of biodetection assay based on energy transfer using Whispering Gallery Modes (WGM) from optical microcavities excited by fluorescent quantum dots as donors and polymeric dye-loaded nanoparticles (dyeNP) as acceptors. The high quality factor of the microcavities enables a strong enhancement of energy transfer to dyeNP acceptors placed within their evanescent field. In particular, we have studied their interactions in a model system using streptavidin-coated microcavities and biotinylated dyeNPs. Upon their specific biomolecular interaction, the dyeNP bind to the microcavity surface, leading to efficient energy transfer, with a typical sensitivity in the fM range, 4-6 orders of magnitude more sensitive than typical FRET assays. We further demonstrate the ultrasensitive detection of DNA oligonucleotides.

Contact :Damien MERTZ  damien.mertz@ipcms.unistra.fr

IPCMS Seminar presented by : Cécilia Ménard-Moyon

Dr. Cécilia Ménard-Moyon  (CNRS, Immunology, Immunopathology and Therapeutic Chemistry, UPR 3572, University of Strasbourg)

Abstract :

The relatively low-cost production of graphene oxide (GO) and its dispersibility in various solvents,
including water, combined with its tunable surface chemistry, make GO an attractive building block to
design multifunctional materials. There are many applications for which it is fundamental to preserve
the intrinsic properties of GO, for instance in the biomedical field. As a consequence, the derivatization
of GO to impart novel properties has to be well controlled and the characterization of the functionalized
samples thoroughly done. Despite the great progress in the functionalization of GO, its chemistry is not
always well controlled and not fully understood.[1] In this context, I will explain some strategies for the
functionalization of GO through the selective derivatization of the epoxides and hydroxyl groups without
alteration of its properties and with biomedical perspectives for anticancer therapy.[2,3] I will also
present how the incorporation of carbon nanomaterials, such as carbon nanotubes and GO, in hydrogels
formed by the self-assembly of aromatic amino acid derivatives can control drug release.[4,5]
[1] Guo S, Garaj S, Bianco A, Ménard-Moyon C, Nat. Rev. Phys., 4 (2022) 247.
[2] Guo S, Nishina Y, Bianco A, Ménard-Moyon C, Angew. Chem. Int. Ed. Engl., 59 (2020) 1542.
[3] Guo S, Song Z, Ji DK, Reina G, Fauny JD, Nishina Y, Ménard-Moyon C, Bianco A, Pharmaceutics, 14 (2022) 1365.
[4] Guilbaud-Chéreau C, Dinesh B, Schurhammer R, Collin D, Bianco A, Ménard-Moyon C, ACS Appl. Mater.
Interfaces, 11 (2019) 13147.
[5] Xiang S, Guilbaud-Chéreau C, Hoschtettler P, Stefan L, Bianco A, Ménard-Moyon C, Int. J. Biol. Macromol., 255
(2024) 127919.