Publications and news by Pr. Marie-Paule Pileni

Synthesis and Self-Assembly Behavior of Charged Au Nanocrystals in Aqueous Solution

Chem. Mater., 2015, 27 (12), pp 4431–4440 A series of water-soluble Au nanocrystals with different core sizes coated by either negatively or positively charged ligands are synthesized. We find a ligand interexchange process takes place when positively and negatively charged nanocrystals are mixed together and heated, resulting in mixed charged zwitterionic nanocrystals. The ligand exchange [...]

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Posted on 3 juillet 2015 by

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Beyond Entropy: Magnetic Forces Induce Formation of Quasicrystalline Structure in Binary Nanocrystal Superlattices

J. Am. Chem. Soc., 2015, 137 (13), pp 4487–4493   Here, it is shown that binary superlattices of Co/Ag nanocrystals with the same size, surface coating, differing by their type of crystallinity are governed by Co–Co magnetic interactions. By using 9 nm amorphous-phase Co nanocrystals and 4 nm polycrystalline Ag nanocrystals at 25 °C, triangle-shaped NaCl-type binary nanocrystal [...]

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Control of the Oxygen and Cobalt Atoms Diffusion through Co Nanoparticles Differing by Their Crystalline Structure and Size

Advanced Functional Materials, Volume 25, Issue 6, pages 891–897, February 11, 2015 The size-dependent Kirkendall effect is studied by using Co nanoparticles. The sizes of Co nanoparticles differing by their crystal structures called nanocrystallinity, namely amorphous, polycrystalline fcc, single crystalline hcp, and single crystalline ε phase, are modulated from 4 to 10 nm. The nanoparticles self-assembled in 2D superlattices and differing [...]

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Metal–Metal Binary Nanoparticle Superlattices: A Case Study of Mixing Co and Ag Nanoparticles

Chem. Mater., 2015, 27 (6), pp 2152–2157 Here, Co/Ag binary nanoparticle superlattices were engineered. It is demonstrated that the Ag/Co nanoparticle size ratio is the dominating factor in the formation of binary nanoparticle superlattices. However, regardless of the relative ratio concentration of Co and Ag nanoparticles, the deposition temperature, Td markedly changes the crystalline structure of binary superlattices. A systematic [...]

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Morphology, Nanocrystallinity, and Elastic Properties of Single Domain ε-Co Supracrystals

J. Phys. Chem. C, 2015, 119 (13), pp 7483–7490   We report on the elastic modulus of 3D superlattices of single domain ε-Co nanocrystals self-assembled in face-centered cubic structures, so-called supracrystals. The effects of nanocrystal size, probe size, and supracrystal morphology on the elastic properties of supracrystals are investigated by nanoindentation measurements using an atomic force microscope. We [...]

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Ag Nanocrystals: 1. Effect of Ligands on Plasmonic Properties

Jingjing Wei, Nicolas Schaeffer, and Marie-Paule Pileni J. Phys. Chem. B, Article ASAP Silver nanocrystals (NCs) stabilized using amine-terminated coating agents (oleylamine or dodecylamine), their size ranging between 2 and 12 nm in diameter, are synthesized by hot injection methods. Their dispersion in size is relatively low (typically below 10%) without the need for a postsynthesis size [...]

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Posted on 7 novembre 2014 by

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Spontaneous Formation of High-Index Planes in Gold Single Domain Nanocrystal Superlattices

Nicolas Goubet, Jianhui Yang, Pierre-Antoine Albouy, and Marie-Paule Pileni Nano Lett., 2014, 14 (11), pp 6632–6638 Crystals of nanocrystals, also called supracrystals and nanocrystal superlattices, are expected to exhibit specific properties that differ from both the corresponding bulk material and nanosized elementary units. In particular, their surfaces have a great potential as nanoscale interaction plateforms. However, control of [...]

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Posted on 22 octobre 2014 by

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Hierarchy in Au Nanocrystal Ordering in Supracrystals: III. Competition between van der Waals and Dynamic Processes

Nicolas Schaeffer, Yanfen Wan, and Marie-Paule Pileni Langmuir, 2014, 30 (24), pp 7177–7181 Au nanocrystals coated with thiol derivatives of varying chain sizes ranging from C12 to C16 were produced; two different size nanocrystals have been synthesized (5 and 7 nm in diameter) for each coating agent. All of those specimens are characterized by a [...]

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Posted on 1 juin 2014 by

Crystal polymorphism: dependence of oxygen diffusion through 2D ordered Co nanocrystals

Zhijie Yang,  Jianhui Yang,  Johanna Bergström,  Khashayar Khazen and   Marie-Paule Pileni Phys. Chem. Chem. Phys., 2014,16, 9791-9796 8 nm Co nanoparticles with various crystalline structures called polymorphs were produced using different synthetic procedures, such as using reverse micelles, the thermal decomposition of organometallics approach or the hot injection process. These 8 nm Co nanoparticles differing by their crystalline structures are [...]

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Negative supracrystals inducing a FCC-BCC transition in gold nanocrystal superlattices

Nicolas Goubet, Marie-Paule Pileni Nano ResearchFebruary 2014, Volume 7, Issue 2, pp 171-179   The growth of nanocrystal superlattices of 5 nm single domain Au nanocrystals at an air-toluene interface induces formation of well-defined thin films (300–400 nm) with large coherence lengths. High-resolution electron microscopy showed that polyhedral holes (negative supracrystal) were formed on the nanocrystal superlattice surface. Formation [...]

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Posted on 16 février 2014 by

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