05/04/2018 Offres d'emploi

Offre de thèse 2018 - ENS Lyon

Thèse à l'ENS Lyon débutant en septembre/octobre 2018 portant sur des assemblages colloïdaux de nanostructures d'or anisotropes

Subject : Colloidal assembly of anisotropic gold nanostructures and optical-plasmonic properties

Key words : nanoparticle, core-shell, gold bipyramid, colloidal assembly, plasmonics, photonic
materials

Project
Assembly of nanoparticles is a hot and challenging topic in (nano)materials chemistry field
since it’s a promising “bottom-up” approach to control micro- and macro-scale structures and
properties of materials. We plan to explore this topic by using gold nano-bipyramids (AuBPs) as
original anisotropic building blocks and study the optical response of the assemblies. Such materials
could find applications in SERS, (bio)sensing and catalysis fields but also in future optoelectronic
devices for light manipulation and emission.[1]
Regarding the strategy, AuBPs will be synthetized according to our efficient method leading to
precise nanostructures exhibiting an intense and sharp plasmon resonance, easily tunable in the
visible-NIR region.[2] Then, the AuBPs surface will be modified (ligand, polymer or SiO2 shell) for
controlling the next assembling step.[3-5] Two major methods are envisaged for colloidal assembling:
(i) deposition of 2D films on a substrate by drop-casting or dip-coating (figure 1 left, right and
ref.[6,7]) and (ii) 3D self-assembling in solution by either induced aggregation or emulsion systems
(Figure 1 middle). The optical and plasmonic properties of the obtained assemblies will be studied
and notably the impact of the nano- and micro-structures (inter-particle distances, packing density,
anisotropy, degree of order and arrangement). Finally, by integrating luminophores in the materials,
emission properties will be investigated, in particular metal enhanced fluorescence/light
amplification/lasing and directionality/polarizability behaviors as a function of the assembly
structure.

Lab & context
The PhD work will be performed in the Chemistry Laboratory of ENS Lyon (UMR 5181)
in the team « Functional Materials and Photonics ». The team develops research on hybrid
(nano)materials devoted to optical applications. In particular the recognized expertise related to
this project lies in the design of original molecular systems, coupled with inorganic materials
(semiconductors, plasmonic or magnetic nanostructures…) and the characterization of optical
interactions and responses (absorption, emission, nonlinear responses…). The applications are in the
fields of optical protection, medical imaging, photocatalysis… Ongoing collaborations with external
group (ILM Lyon, CEA Saclay, Wroclaw University) will be exploited in order to characterize specific
optical phenomena (lasing, charge/energy transfers…) on particle assemblies.

Skills/techniques
Synthesis, surface modification and assembly of hybrid NPs - Spectroscopy (UVvis-
NIR absorption, fluorescence) - electron microscopy (SEM, TEM) - scattering techniques (DLS,
SAXS, GISAXS).

Candidate profileThe candidate should have a Master’s degree or equivalent for registration to aPhD program, with a high academic and scientific level in general chemistry, materials chemistry or physical chemistry of materials. In addition, he/she should be highly motivated by experimental work, curious and comfortable with bibliography and resources.

Starting date: Sept./Oct. 2018 Application online: www.edchimie-lyon.fr


References
[1] S. Parola, B. Julian-Lopez, L. D. Carlos, C. Sanchez, Optical Properties of Hybrid Organic-Inorganic
Materials and their Applications, Adv. Funct. Mater., 2016, 26 (36), 6506-6544.
[2] D. Chateau, A. Liotta, F. Vadcard, J. R. G. Navarro, F. Chaput, J. Lermé, F. Lerouge, S. Parola, From
gold nanobipyramids to nanojavelins for a precise tuning of the Plasmon resonance to the infrared
wavelengths. Experimental and theoretical aspects, Nanoscale, 2015, 7, 1934.
[3] H. Lundén, A. Liotta, D. Chateau, F. Lerouge, F. Chaput, S. Parola, C. Brännlund, Z. Ghadyani, M.
Kildemo, M. Lindgren, C. Lopes, Dispersion and self-orientation of gold nanoparticles in sol-gel hybrid
silica – optical transmission properties, J. Mater. Chem. C, 2015, 3, 1026.
[4] D. Chateau, A. Liotta, H. Lundén, F. Lerouge, F. Chaput, D. Krein, T. Cooper, C. Lopes, M. Lindgren,
S. Parola, Long Distance Enhancement of Nonlinear Optical Properties Using Low Concentration of
Plasmonic Nanostructures in Dye Doped Monolithic Sol–Gel Materials, Adv. Funct. Mater., 2016, 26
(33), 6005-6014.
[5] D. Chateau, A. Liotta, D. Gregori, F. Lerouge, F. Chaput, A. Désert, S. Parola, Controlled surface
modification of gold nanostructures with functionalized silicon polymers, J Sol-Gel Sci Technol., 2016,
81, 147.
[6] Q. Shi, K. J. Si, D. Sikdar, L. W. Yap, M. Premaratne, W. Cheng, Two-Dimensional Bipyramid
Plasmonic Nanoparticle Liquid Crystalline Superstructure with Four Distinct Orientational Packing
Orders., ACS Nano, 2016, 10, 967.
[7] Konrad Cyprych, Denis Chateau, Anthony Désert, Stephane Parola, Jaroslaw Mysliwiec, Plasmonic
nanoparticles driven enhanced light amplification in a local 2D and 3D self-assembly, 2018, under
review.

 

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