Highly stable, low-strain flexible sensors based on gold nanoparticles and silica nano-helices
Flexible strain sensors based on nanoparticle (NP) arrays have great potential for future applications such as electronic skin, flexible touch screens, healthcare sensors and robotics. However, although these sensors can exhibit high sensitivity, they are generally not very stable under mechanical cycling and often exhibit significant hysteresis, making them unsuitable for practical applications. This is why we have developed a general strategy for the innovative synthesis of strain sensors based on arrays of silica nanohelices grafted with gold nanoparticles (AuNPs) that can overcome these critical aspects. These 10 nm gold nanoparticles are functionalized with mercaptopropionic acid and different ratios of thiol-polyethylene glycol-carboxylic acid to optimize the colloidal stability of the resulting nanohelice@AuNPs nanocomposite suspensions, control their aggregation state and adjust the thickness of the insulating layer. They are then covalently grafted onto the nanohelice surface in a well-defined arrangement that follows the helicity of the silica template. They are then aligned by dielectrophoresis between interdigitated electrodes on a flexible substrate. The flexibility, stability and sensitivity of these sensors are then characterized by electromechanical measurements and scanning electron microscopy. These deformation sensors based on NH@AuNPs nanocomposites are much more stable than those containing only nanoparticles, with significantly reduced hysteresis and high sensitivity at very low deformations. They can retain their sensitivity even after 2 million consecutive cycles with virtually unchanged reactivity. This enhanced performance is due to their mechanical stability and the use of nanohelices as stable mechanical templates.
Amestoy, A.; Rangra, A.; Mansard, V.; Saya, D.; Pouget, E.; Mazaleyrat, E.; Severac, F.; Bergaud, C.; Oda, R.; Delville, M.-H., Highly Stable Low-Strain Flexible Sensors Based on Gold Nanoparticles/Silica Nanohelices. ACS Applied Materials & Interfaces 2023, 15, 39480-39493, https://doi.org/10.1021/acsami.3c05852
How are silicon particles fabricated from a silicon rich oxide matrix?
Particle growth is followed in real time during the disproportionation reaction of silicon oxide into silicon and silica. By using an environmental in situ microscope, we have discovered that there exists at least two growth methods occuring simultaneously: particle-particle coalescence and the displacement of liquid-like spherical particles through the matrix. Such nano-objects present an interest for isotropic optical materials with applications in metamaterials.
Cynthia Cibaka-Ndaya, Kevin O’Connor, Emmanuel Opeyemi Idowu, Megan A. Parker, Eric Lebraud, Sabrina Lacomme, David Montero, Paula Sanz Camacho, Jonathan G.-C. Veinot, Ioan-Lucian Roiban, Glenna L. Drisko, Understanding the formation mechanisms of silicon particles from the thermal disproportionation of hydrogen silsesquioxane. Chem. Mater. 2023 vol.?, p.? (10 p.). https://dx.doi.org10.1021/acs.chemmater.3c01448.
How are bimetallic copper-based nanowires synthesized?
While the literature contains hundreds of protocols to prepare Cu-based nanoalloys, it remains a challenge to synthesize bimetallic nanowires in which the two metals are intimately bounded. This review article presents the current research landscape in making such nanosystems.
Križan et al 2023 Nano Ex. https://doi.org/10.1088/2632-959X/ad0168
How to make ultrathin gold nanoshells with well-controlled resonances at infrared wavelengths?
Our manuscript describes a way to make ultrathin gold nanoshells by combining multiple synthesis steps involving inorganic growth, surface functionalization, metal deposition and post-synthetic treatment. The nanoshells are made of a dielectric core surrounded by a thin metallic shell (< 10 nm). Such nano-objects are of interest for isotropic optical materials with applications in biology, imaging, energy saving windows and optical communications.
Lermusiaux L., Plissonneau M., Bertry L., Drisko G. L., Buissette V., Le Mercier T., Duguet E. and Tréguer-Delapierre M. Seeded growth of ultrathin gold nanoshells using polymer additives and microwave radiation. Sci. Rep. 2021 vol.11, p.17831 (10 p.). 10.1038/s41598-021-97171-0.
Towards Huygens’ Sources with dodecahedral plasmonic clusters
Many applications in photonics require controlling the phase and amplitude of light at a local scale. Huygens’ sources enable this by letting multipoles of opposed parity interfere in order to scatter light in the forward direction with a strong efficiency. Recent literature has shown that metasurfaces composed of Huygens’ sources make excellent flat optical components that realize specific functions such as lensing, perfect absorption, imaging, holography, polarization control, wavefront control or even bio-sensing. All realizations made thus far rely on shaping Huygens’ sources using lithography and are intrinsically anisotropic. As a result, the sources are bound to an array and a substrate. Here, however, we design and fabricate highly symmetric dodecahedral plasmonic clusters by nanochemistry that act as Huygens’ sources.
Laurent Lermusiaux, Véronique Many, Philippe Barois, Virginie Ponsinet, Serge Ravaine, Etienne Duguet, Mona Tréguer-Delapierre, et Alexandre Baron, Nano Lett. 2021, 21, 5, 2046-2052. 10.1021/acs.nanolett.0c04666
Interested in a synthesis that makes it possible to produce ultralong silver nanowires? here is one of our latest articles on silver nanowires and the manufacture of high performance transparent electrodes à basse température
Read article: Madeira A., Papanastasiou D. T., Toupance T., Servant L., Tréguer-Delapierre M., Bellet D. and Goldthorpe I. A. Rapid synthesis of ultra-long silver nanowires for high performance transparent electrodes. Nanoscale Adv. 2020 vol. 2, n°9, p. 3804-3808. 10.1039/D0NA00392A
Optical materials: We are interested in making materials that have a negative index of refraction. No naturally occurring material that we know of has this property, but it could be achieved in an metamaterial. An optical metamaterial is composed of elements that are smaller than the wavelength light in interesting ways. In this article, we have developed a new way to make optical metamaterials through self-assembly in collaboration with the group of V. Manoharan (U.Harvard).
Read article: N. Tanjeem, C. Chomette, N. Schade, S. Ravaine, E. Duguet, M. Tréguer-Delapierre, V. Manoharan. Polyhedral plasmonic nanoclusters through multi-step colloidal chemistry. Material Horizons, 2021. 10.1039/D0MH01311K
Gold nanocages: a new synthetic recipe for making hollow nanoscale structures.
Gold nanocages with 2, 3, 4, 6 and 12 windows are elaborated using a multi-step colloidal synthesis approach. This versatile route allows a guest spherical particle to be included within the nanocages. Their optical properties are compared with simulation predictions.
Read article: C. Hubert, C. Chomette, A. Desert, A. Madeira, A. Perro, I. Florea, . Ihiawakrim, O. Ersen, A. Lombardi, E. Pertreux, F. Vialla, P. Maioli, A. Crut, N. Del Fatti, F. Vallée, J. Majimel, S. Ravaine, E. Duguet, M. Tréguer-Delapierre. Versatile template-directed synthesis of gold nanocages with a predefined number of windows. Nanoscale Horizons, 2021. 10.1039/D0NH00620C
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