Metamat
ABOUT US
arrow_drop_down
Nanotechnologies

Metamat

We are a team of researchers specialized in nanosciences and we aim at building new materials with enhanced optical and mechanical properties.
Our expertise span from the synthesis of the nanoproducts and their self-assembly to their structural characterization.

Latest News
Formation of kinetically trapped small clusters of PEGylated gold nanoparticles revealed by the comb

26/10/2022.

Gold nanoparticles coated with polyethylene glycol (PEG) are able to form clusters due to the collapse of the surface-grafted polymer chains when the temperature and ion concentration of the aqueous medium are increased. The chain collapse reduces the steric repulsion, leading to particle aggregation. In this work, we combine small angle X-ray scattering (SAXS) and visible light spectroscopy to elucidate the structure of the developing clusters. The structure derived from the SAXS measurements reveals a decrease in interparticle distance and drastic narrowing of its distribution in the cluster, indicating restricted particle mobility and displacement within the cluster. Surprisingly, instead of forming a large crystalline phase, the evolving clusters are composed of about a dozen particles. The experimental optical extinction spectra measured during cluster formation can be very well reproduced by optical simulations based on the SAXS-derived structural data.

 

Thanks to Daniel and Andras from the Centre for Energy Research (Budapest, Hungary) for this nice collaboration.

Longitudinal and Transversal Directed Overgrowth of Pentatwinned Silver Nanorods with Tunable Optica

07/07/2022

Silver nanorods (AgNRs) with a controllable aspect ratio can be formed by templated growth from pentatwinned seeds. However, it is challenging to control the volume of the AgNRs and their aspect ratio independently because of the selective protection against growth of the lateral facets by halides. Here we demonstrate the preparation of AgNRs with tunable width via the addition of dimethyl sulfoxide (DMSO). AgNRs with custom dimensions were produced by separating the longitudinal and transverse growth in a two-step procedure. In the first step, the length is tuned by directing the overgrowth on the {111} tips of the AgNRs. In the second step, the width is adjusted by directing the overgrowth on the {100} lateral facets in the presence of DMSO. AgNRs of varying dimensions were obtained and characterized by a combination of techniques including scanning transmission electron microscopy, electron energy loss spectroscopy, and cathodoluminescence, which are, respectively, sensitive to the extinction and scattering component of the AgNRs’ response. This method allows tuning the plasmon energies, but also the ratio of the scattering and absorption contributions.

https://doi.org/10.1021/acs.jpcc.2c02846

Jieli presented her PhD

05/07/2022

Jieli Lyu successfully presented her PhD after 4 years in the lab under the supervision of Doru, Cyrille and Marianne. It was pointed out that she arrived as a young student and will leave the lab as a young scientist. Congratulation Jieli!

 

 

Shape-Controlled Second-Harmonic Scattering from Gold Nanotetrapods

Abstract Image

02/06/2022

In the search for efficient building blocks for nonlinear metamaterials, plasmonic nanoparticles have received considerable attention. Their quadratic nonlinear optical properties result from a complex interplay between the nature of the bulk material, the object shape, surface defects, and retardation effects. This versatility can be used to tailor the properties of the resulting material. However, despite extensive investigation, separating and controlling these contributions still pose a challenge. In this report, we control the morphology of colloidal gold nanoparticles with tetrahedral symmetry and explore their second harmonic scattering response. The material itself is centrosymmetric but not the shape, conferring to the first hyperpolarizability an almost purely octupolar symmetry. Gradually reshaping the nanoparticles into spheres (and thus decreasing their asymmetry) reduces their nonlinear response, showing that it is controlled by the morphology. These results open the way toward new kinds of nonlinear plasmonics platforms and imaging probes.

https://doi.org/10.1021/acs.jpcc.2c01867

Acoustic Vibration Modes of Gold–Silver Core–Shell Nanoparticles

30/05/2022

Bimetallic Au/Ag core–shell cuboid nanoparticles (NPs) exhibit a complex plasmonic response dominated by a dipolar longitudinal mode and higher-order transverse modes in the near-UV, which may be exploited for a range of applications. In this paper, we take advantage of the strong signature of these modes in the NP ultrafast transient optical response, measured by pump-probe transient absorption (TA) spectroscopy, to explore the NP vibrational landscape. The fast Fourier transform analysis of the TA dynamics reveals specific vibration modes in the frequency range 15–150 GHz, further studied by numerical simulations based on the finite element method. While bare Au nanorods exhibit extensional and breathing modes, the bimetallic NPs undergo more complex motions, involving the displacement of facets, edges and corners. The amplitude and frequency of these modes are shown to depend on the Ag shell thickness, as the silver load modifies the NP aspect ratio and mass. Moreover, the contributions of the vibrational modes to the experimental TA spectra are shown to vary with the probe laser wavelength at which the signal is monitored. Using the combined simulations of the NP elastic and optical properties, we elucidate this influence by analyzing the effect of the mechanisms involved in the acousto-plasmonic coupling.

Thanks to the collaborators for this nice work. https://doi.org/10.3390/chemosensors10050193

Laser-Driven Bubble Printing of Plasmonic Nanoparticle Assemblies onto Nonplasmonic Substrates

 28/04/2022

The use of optically controlled vapor bubbles for controlled synthesis and deposition at interfaces is a promising emerging technique, which is intrinsically limited by the ability of the system to provide enough heat for bubble formation that is typically addressed using a plasmonic substrate. Herein, a simple and fast method for laser-controlled printing of plasmonic nanoparticles onto nonplasmonic substrates is shown. The laser fluence needed to print the nanoparticle was lowest for nanoparticles in resonance with the laser wavelength, but the technique is also effective off-resonance. Hierarchical assemblies were obtained, where melting was observed up to a micron from the focal point of the laser beam. The assemblies show plasmonic properties in the unmelted region, as shown by surface-enhanced Raman scattering spectroscopy measurements. This work will lead to future studies on controlling the hierarchical structure of nanoparticle assemblies formed at the bubble interface toward applications in sensing and devices.

https://doi.org/10.1021/acs.jpcc.2c02414

Thanks to Eric Hill and his nice microscope for printing plasmonic patterns.

Double-lattice packing of pentagonal gold bipyramids in supercrystals with triclinic symmetry

24/03/2022

Pentagonal packing is a long-standing issue and a rich mathematical topic, brought to the fore by recent progress in nanoparticle design. Gold pentagonal bipyramids combine five-fold symmetry and anisotropy and their section varies along the length. In this work, we obtain colloidal supercrystals of pentagonal gold bipyramids in a compact arrangement that generalizes the optimal packing of regular pentagons in the plane. Multimodal investigations reveal a two-particle unit cell with triclinic symmetry, a lower symmetry than that of the building blocks. Monte Carlo computer simulations show that this lattice achieves the densest possible packing. Going beyond pentagons, further simulations show an odd-even effect of the number of sides on the packing: odd-sided bipyramids are non-centrosymmetric and require the double-lattice arrangement to recover inversion symmetry. The supercrystals display a facet-dependent optical response that is promising for sensing, metamaterials applications and for fundamental studies of self-assembly processes.

10.1002/adma.202200883

Welcome Jianan!

28/01/2021

 

I obtained my Bachelor of Engineering in Nano Materials and Technology from Soochow University in China. During my undergraduate study, I worked on several projects related to nanoscaled functional materials for energy conversion and storage under the supervision of Prof. Yanguang Li.

 

I am now the M2 student from Erasmus Mundus Joint Master program: SERP+. Currently, I am working on my thesis project about self-assembly of colloidal liquid crystal in levitation under the supervision of Dr. Cyrille Hamon and Dr. Erwan Paineau.

Happy 2022!

credit photo MATRIX team: Fréedericksz transition in a biaxe smectic phase

Unveiling the Coupling of Single Metallic Nanoparticles to Whispering-Gallery Microcavities

16/12/2021

Abstract Image Nice work published in collaboration with the STEM group @ LPS

10.1021/acs.nanolett.1c03826

Whispering-gallery mode resonators host multiple trapped narrow-band circulating optical resonances that find applications in quantum electrodynamics, optomechanics, and sensing. However, the spherical symmetry and low field leakage of dielectric microspheres make it difficult to probe their high-quality optical modes using far-field radiation. Even so, local field enhancement from metallic nanoparticles (MNPs) coupled to the resonators can interface the optical far field and the bounded cavity modes. In this work, we study the interaction between whispering-gallery modes and MNP surface plasmons with nanometric spatial resolution by using electron-beam spectroscopy with a scanning transmission electron microscope. We show that gallery modes are induced over a selective spectral range of the nanoparticle plasmons, and additionally, their polarization can be controlled by the induced dipole moment of the MNP. Our study demonstrates a viable mechanism to effectively excite high-quality-factor whispering-gallery modes and holds potential for applications in optical sensing and light manipulation.

Thanks to the STEM group @ LPS and especially to Yves Auad whom carried out the experiments.

Gold-clay nanocomposite colloids with liquid-crystalline and plasmonic properties

14/09/2021

Imparting liquid-crystal (LC) materials with the plasmonic properties of metal nanoparticles is actively pursued for applications. We achieved this goal by synthetizing gold nanoparticles onto clay nanosheets, leading to nematic nanocomposite suspensions. Optical observations and structural analysis show the growth of the gold nanoparticles without altering the LC properties of the nanosheets. These colloids display plasmonic structural colours and they can be aligned by an electric field, which is relevant for fundamental and materials chemistry of colloidal LC.

DOI: https://doi.org/10.1039/D1CC03826E

Doping Liquid Crystals of Colloidal Inorganic Nanotubes by Additive-Free Metal Nanoparticles

25/05/2021

https://doi.org/10.1021/acs.jpclett.1c01311

Doping liquid-crystal phases with nanoparticles is a fast-growing field with potential breakthroughs due to the combination of the properties brought by the two components. One of the main challenges remains the long-term stability of the hybrid system, requiring complex functionalization of the nanoparticles at the expense of their self-assembly properties. Here we demonstrate the successful synthesis of additive-free noble-metal nanoparticles at the surface of charged inorganic nanotubes. Transmission electron microscopy and UV-visible spectroscopy confirm the stabilization of metallic nanoparticles on nanotubes. Meanwhile, the spontaneous formation of liquid-crystals phases induced by the nanotubes is observed, even after surface modification with metallic nanoparticles. Small-angle X-ray scattering experiments reveal that the average interparticle distance in the resulting hybrids can be easily modulated by controlling electrostatic interactions. As a proof-of-concept, we demonstrate the effectiveness of our method for the preparation of homogeneous transparent hybrid films with a high degree of alignment.

Symmetry breaking in seed-mediated silver nanorod growth induced by dimethyl sulfoxide

12/04/2021

https://doi.org/10.1021/acs.chemmater.1c00454

Engineering symmetry breaking in seed-mediated growth is a fundamental challenge to produce colloidal nanocrystals with controlled morphologies and properties. In this work, we show a simple, aqueous approach to breaking the inversion symmetry of silver nanorods by restricting growth to one end of the pentatwinned gold bipyramid seed. Controlled addition of dimethyl sulfoxide (DMSO) allows us to tune both the symmetry and the length and width of the objects. Simulations and experiments demonstrate the adsorption of DMSO, which displaces interfacial water, reduces binding of surfactant and chloride ions at the gold surface, and slows down the deposition kinetics of silver. Besides showing the potential of DMSO for controlling the synthesis of complex nanostructures, this work opens new perspectives for the study of the physical properties of non-centrosymmetric nanoparticles, e.g. by controlling their plasmon modes and their second-harmonic generation efficiency.

Structure and Formation Kinetics of Millimeter-Size Single Domain Supercrystals

31/03/2021

https://doi.org/10.1002/adfm.202101869

 

Organizing nanoparticles (NPs) into periodic structures is a central goal in materials science. Despite progress in the last decades, it is still challenging to produce macroscopic assemblies reliably. In this work, we report the analysis of the pervaporation-induced organization of gold octahedra into supercrystals within microfluidic channels using a combination of X-ray scattering techniques and FIB-SEM tomography. The results reveal the formation of a single-domain supercrystal with a monoclinic C2/m symmetry and long-range order extending over the dimensions of the microfluidic channel, covering at least 1.7x0.3 mm2. Time-resolved small angle X-ray scattering analysis showed that the formation of the superlattice involves an accumulation of the NPs within the channel before the nucleation and growth of the supercrystal. The orientation of the crystal remains unchanged during its formation, suggesting a growth mechanism directed by the channel interface. Together, these results show the potential application of the pervaporation strategy to providing spatially determined control over NP crystallization, which can be used for the rational fabrication of nanomaterial architectures.

Research
Plasmonic NPs Synthesis by colloidal chemistry

 

Selection of TEM images of Au or Au@Ag NPs with various morphology obtained in the team. The colors distinct series of nanocrystal: gold bipyramids of different size (purple), Au@Ag nanorods of varying shell thickness (red), Au@Ag bipyramids of varying shell length (green).

Shaping nanomaterials

Construction of nanoscale devices is a crucial step toward the sucess of nanotechnologies in a variety of fields. Although construction by addition of individual building blocks might appear impossible without using nanomachines, it can actually be carried out by simply exploiting the different magnitude of attractive and repulsive interaction forces at the nanoscale. For example, gravity is negligible for nanoparticles, but other forces become dominant and require the nanoparticles to be coated with selected molecules. Thus, one can simply let the solvent evaporate and wait the nanoparticles to organize into ordered structures without any intervention. Such strategy is one of the core of the concept of self-assembly.

Gold and silver nanoparticles

Plasmonic nanoparticles (Au and Ag) have been object of fascination since ancient time for the preparation of stained glass. Such elementary building block are extremly robust and their use in monuments stand the test of time. A not too far example from the laboratory is the "Sainte-Chapelle du Palais" at "l'île de la cité" in Paris (see image, wikipédia). This phenomenon, commonly witnessed by everyone, originates from the plasmonic properties of metallic nanoparticles. 

 

Optical properties of nanoparticles

The strong optical properties of nanoparticles (e.g. plasmonic or semiconducting) can be tuned across the visible to the mid infra-red range by modifying their size and shape. When such nanoparticles are organized in ensembles, collective properties are obtained that differ from those of individual particles and the resulting optical properties can be further tuned and even amplified. In particular, plasmon coupling in small gaps (1–10 nm) between plasmonic nanoparticles results in intense electric fields (i.e.,hot-spots) that can be exploited for many purposes, such as sensing, biomaterials, metamaterials design, switching devices, and so forth.

Use of light to study nanoparticles self assembly

We use UV/Vis spectrometry and X-ray scattering tecniques (SAXS) to study nanoparticles super-structures. The structural study of the material is the first step before understanding its overall properties and considering applications. SAXS is an experimental technique used to study the structural properties of materials and gives information on the size and orientation of the nanoparticles, their arrangement, the characteristic interdistances and the possible long-range organization. In a scattering experiment, ordered phases give diffraction signals that are called Bragg peaks. Analysis of such signals requires adapting standard methods of crystallography to the nanoscale, as the relevant length scale is much larger than the atomic scale. UV/Vis spectrometry is used complementary to measure the collective optical properties. Both techniques can be used in situ to study self assembly's pathways. 

 

Mesoporous materials

A mesoporous material is a material containing pores with diameters between 2 and 50 nm. We are devising materials containing a mesoporous architecture to enhance size and shape selectivity for guest molecules or to template nanoparticles synthesis. 

Team
Team MATRIX

 

We are all working in the team MATRIX at the Laboratoire de Physique des Solides (LPS) in Orsay. The LPS is part of the vibrating Paris region fostering interaction with fellow researchers and visiting scientist.

 

LPS website: https://www2.lps.u-psud.fr/

MATRIX team website: https://equipes2.lps.u-psud.fr/matrix/

Cyrille Hamon

Cyrille Hamon obtained his Ph.D. from the University of Rennes 1 (France) under the supervision of Pascale Even-Hernandez and Valérie Marchi in 2013. He was a postdoctoral fellow in Luis Liz-Marzán laboratory (CIC Biomagune, Spain) from 2014 to 2016. He then joined the laboratories of Gaëlle Charron and Pascal Hersen (MSC, Université Paris 7) from 2016 to 2017.

He has been appointed in 2017 with a permanent CNRS position in the Laboratoire de Physique des Solides in Orsay.

His current interest focuses on devising new plasmonic architectures for sensing and catalytic applications.

 

 

 

Alumni

Wajdi Chaâbani - 2022

Wajdi Chaâbani obtained his Ph.D. from the University of Technology of Troyes (France) and the University of Sciences of Sfax (Sfax, Tunisie) under the supervisions of Jérôme Plain and of Abdallah Chehaidar in July 2019. He was a postdoctoral researcher in IEMN Laboratory (Lille, France) from September 2019 to August 2020. He then joined the Laboratoire de Physique des Solides in Orsay (France) as postdoctoral researcher.

Currently, his interest focuses on self-assembling plasmonic nanoparticles in confinement. The nanostructuration will be resolved at the single supercrystal level using an innovative Small Angle X-ray Scattering (SAXS) setup developed on a synchrotron beamline.(SWING, @SOLEIL).

He is now doing a postdoc at ITODYS (Université Paris-Cité)

Jianan Qian - 2022

I obtained my Bachelor of Engineering in Nano Materials and Technology from Soochow University in China. During my undergraduate study, I worked on several projects related to nanoscaled functional materials for energy conversion and storage under the supervision of Prof. Yanguang Li.

 

I am now the M2 student from Erasmus Mundus Joint Master program: SERP+. Currently, I am working on my thesis project about self-assembly of colloidal liquid crystal in levitation under the supervision of Dr. Cyrille Hamon and Dr. Erwan Paineau.

Jieli Lyu - 2022

Jieli Lyu completed her M.S. degree at the Key Laboratory of Applied Surface and Colloid Chemistry of Shaanxi Normal University. She studied under the supervision of Prof. Junxia Peng and Prof. Yu Fang, and her main research topics were (1) synthesis and characterization of amphiliphic compounds; (2) formulation and performances of the emulsions; (3) emulsion-templated preparation of porous materials and their catalytic performance.

She started her PhD in october 2018. Her research interest focuses on nanomaterials with a multiscale organization as well as shedding light on the self-assemblies pathways using light scattering techniques. 

Samantha Roque - 2021

Samantha Roque earned her Bachelor of Science in Chemistry (2017) and in Materials Science Engineering (2018) from Ateneo de Manila University in the Philippines. She worked on printable carbon composites and biosilica inks for perovskite solar cells under Erwin P. Enriquez, Ph.D. 
 
She is now doing her master's degree under the Erasmus Mundus Joint Master Degree SERP+. She is at present doing her internship on Anisotropic plasmonic-semiconductor nanocomposites for photocatalytic applications which is a joint project between the “Institut de Chimie Physique” and the “Laboratoire de Physique des Solides” supervised by Cyrille Hamon Ph.D. and ‪Mohamed Nawfal Ghazzal, Ph.D.  
 
She is now doing a PhD at Université du Sud Toulon Var

  Masa Johar - 2021

Masa Johar graduated from An-Najah National University, Palestine (2020),  with a bachelor's degree in Applied Chemistry. She joined University of Paris Saclay in September  2020 to start her master's degree within the Chemistry International Track program for two years.
 
Currently, she is doing her M1 internship on "Colloidal chemistry of plasmonic triangular nanoplatelets" under supervision of Prof. Cyrille Hamon at the Laboratory of Solid Physics (LPS). Her main motivation is to find the best protocol for synthesizing triangular gold nanoparticles.   
 
Finally, she is looking forward to being a highly skilled researcher enthusiastic about supporting advancements in the nanotechnology world, passionate about increasing knowledge to drive growth and needed improvements related to sustainable developments in Energy, Health and Environment.

 Kinanti Aliyah - 2019

Kinanti Hantiyana Aliyah earned her Bachelor of Science in Chemistry from Tohoku University, Japan (2017). She worked in Institute for Materials Research for her bachelor thesis, under supervision of Prof. Hitoshi Miyasaka synthesizing novel building blocks for donor-acceptor metal-organic frameworks.

Currently, she is in her second-year master Erasmus Mundus Joint Master Degree SERP+, working on thesis project about synthesis and characterization of anisotropic bimetallic nanoparticles in real time under supervision of Dr. Cyrille Hamon and Dr. Doru Constantin.

Additionally, believing education should be accessible to all, she co-founded and actively maintains an online-based knowledge-sharing platform for Indonesians (ajarbelajar.com).

Kinanti is now doing her PhD at the Paul Scherrer Institut (Switzerland)

 

 

 

Jules Marcone

Jules Marcone graduated in 2022 from the Paris-Saclay University in 2022 with a Magister of Molecular Physicochemistry, focusing on Inorganic, Physical, and Materials Chemistry. During his study, he developed various skills in characterization methods (SAXS, XRD, SEM, etc.), and also in nanoparticle synthesis and self-assembly.  
Jules started his PhD in October 2022 under the supervision of Marianne Impéror-Clerc and Cyrille Hamon at the LPS, on the synthesis and self-assembly of nanoparticles focusing particularly on cobalt nanorods, aiming for collective magnetic properties.

Emmanuel Beaudoin

Emmanuel Beaudoin is an Associate Professor in University Paris-Saclay. He obtained his PhD at the “Laboratoire de Physico-Chimie des Polymères” in « Université de Pau » in 2001, and his HDR (Habilitation à Diriger des Recherches) in « Université de Marseille » in 2014, the same year he has joined the Laboratoire de Physique des Solides. He is involved in physical and physico-chemical studies of nanostructured and hybrid polymeric materials. He is interested in the relationship between structure and physical properties of these materials, at rest and under strain. The main techniques he uses are Small Angles X-ray scattering (with laboratory equipment and synchrotron - ESRF, SOLEIL), optical microscopy, Differential Scanning Calorimetry, UV-vis spectroscopy and spectrofluorimetry.

Patrick Davidson

 

After graduating with a chemical engineering degree from Ecole Supérieure de Physique et Chimie Industrielles de la ville de Paris, a PhD and an Habilitation à diriger des recherches, Patrick Davidson was appointed CNRS Research Director, in 2003, at Laboratoire de Physique des Solides of Université Paris-Sud in Orsay.

His research work focuses on the structural and physical properties of complex fluids such as molecular and polymer liquid crystals, colloidal suspensions and surfactant solutions. He has also recently been involved in the study of hybrid systems prepared by doping liquid-crystalline matrices with mineral nanoparticles. His favorite techniques are X-ray scattering, polarized-light microscopy, and magneto- and electro-optics. His research activity involves frequent contacts with chemists and theoretical physicists.

He is also presently in charge of the “Soft matter and biophysics” research axis of the LPS.

 

Marianne Impéror-Clerc

Marianne Impéror-Clerc has a permanent position at CNRS as ‘directrice de recherche’. She studied Physics at the ENS de Saint-Cloud (1986-1990) where she passed the ‘aggrégation de Physiques’ (1989) before obtaining her PhD (1992) and HdR ‘Habilitation à diriger des recherches’ (2007) at the Université Paris-Sud in Orsay.

Her research is devoted to structural studies of self-assembled systems and her favorite experimental tool is Small Angle Scattering using X-rays or neutrons (SAXS and SANS). 

For example, for mesoporous materials, the control of the architecture of the porosity allows to optimize transport properties. Main goal is to control the nanostructure during the synthesis of such materials. For this, time-resolved scattering experiments allow to follow in real time the formation of the materials and to elucidate the mechanisms involved. Her research thus lies at the frontier between Soft Matter and Materials Chemistry.

She is alos regularly involved in activities about Crystallography for education and the general public (http://www.cristallo2014.u-psud.fr/)

 

 

 

Doru Constantin

Doru Constantin studied physics at the University of Bucharest and at the Ecole Normale Supérieure de Lyon and was awarded his PhD at the latter institution in 2002. After a Marie Curie Individual Fellowship at the University of Goettingen he obtained a permanent CNRS position at the LPS in 2005.

His activity revolves around the characterization of soft matter systems, often composed of an anisotropic medium doped with nanoparticles.

These studies are performed using modern, synchrotron-based techniques, such as time-resolved, dynamic, or surface-sensitive X-ray scattering and involve a substantial amount of modelling and analysis, using statistical theory or continuum media models.

 In 2021, Doru joined the Institut Charles Sadron in Strasbourg.