Fabien Grasset

• Dr.
• Research Director at French National Centre for Scientific Research

Transition metal carbides and nitrides demonstrate very interesting electrocatalytic properties, close to those of noble metals. Indeed,platinum being a scarce and expensive element, carbides and nitrides could be an interesting alternative to make this technology economically viable. Recently, different authors reported promising (electro)catalyti...

Plasmonic silver-decorated TiO2 inverse opal has shown an interesting potential for photocatalysis owing to its physically tunable optical absorbance, highly active area, and flexible fabrication. In this study, electrophoretic deposition was used as a key technique to overcome the disadvantages of traditional inverse opal (IO)-fabricating methods,...

The comparison between as-received and multistage annealed NiFe2O4@SiO2 (NFO@SiO2) core-shell nanoparticles is presented. The studied ferrites were synthesized by co-precipitation followed by microemulsion. The presence of cubic inverse spinel ferrite structure with tetrahedral and octahedral iron occupancy is confirmed in all analyzed samples. The...

Metal atom clusters are well-defined nanoscale objects containing a precise number of metal atoms and ligands. Face-capped cluster units of the type [{M6Li8}L’a6] (M = Mo, Re, L = S,...

Near‐infrared (NIR) laser annealing is successfully used to crystallize TiO2 thin films from a sol–gel solution deposited on gold nanoparticle arrays (AuNPs). The AuNPs are used as nano‐heaters allowing a local temperature increase up to 500 °C in the film. The temperature reached under the laser is deduced from the presence of the anatase phase in...

The emergence of multidrug-resistant microbial pathogens poses a significant threat, severely limiting the options for effective antibiotic therapy. This challenge can be overcome through the photoinactivation of pathogenic bacteria using materials generating reactive oxygen species upon exposure to visible light. These species target vital compone...

The high-performance defect-rich MoS2 dominated by sulfur vacancies as well as Mo-rich environments have been extensively studied in many fields, such as nitrogen reduction reactions, hydrogen evolution reactions, as well as sensing devices for NH3, which are attributed to the under-coordinated Mo atoms playing a significant role as catalytic sites...

This study deals with the nanoarchitectonic concept applied to the design of photoelectrodes built up on two types of cluster core building blocks, namely {Re6Si 8} and {Re6Sei 8}. The effect of the nature of the metal/ligand on photo‐induced conductivity properties was thus investigated through an in‐depth photoelectrochemical study and it was rat...

Micro- and nanopatterning of metal oxide materials is an important process to develop electronic or optoelectronic devices. ZnO is a material of choice for its semiconducting and photoluminescence properties. In the frame of the nanoarchitectonics concept, we have developed and investigated a new process that relies on direct write laser patterning...

This review is dedicated to various functional nanoarchitectonic nanocomposites based on molecular octahedral metal atom clusters (Nb6, Mo6, Ta6, W6, Re6). Powder and film nanocomposites with two-dimensional, one-dimensional and zero dimensional morphologies are presented, as well as film matrixes from organic polymers to inorganic layered oxides....

This short communication reports on the facile and scalable synthesis and characterization of molybdenum carbides/carbon nanocomposites prepared by laser pyrolysis in a one-step process. Water and commercial molybdenum oxide were used as low-cost environmentally friendly precursors. The nanocomposites are mainly composed of two types of carbides wi...

The development of highly ultraviolet (UV) and near-infrared (NIR) absorbent transparent coatings is an important enabling technology and area of research for environmental sustainability and energy conservation. Different amounts of K4[{Nb5TaXi 12}Xa 6] cluster compounds (X = Cl, Br) dispersed into polyvinylpyrrolidone matrices were prepared by a...

In the frame of the nanoarchitectonic concept, the objective of this study was to develop simple and easy methods to ensure the preparation of polymorphic HfO2 thin film materials (<200 nm) having the best balance of patterning potential, reproducibility and stability to be used in optical, sensing or electronic fields. The nanostructured HfO2 thin...

The antagonism between global energy needs and the obligation to slow global warming is a current challenge. In order to ensure sufficient thermal comfort, the automotive, housing and agricultural building sectors are major energy consumers. Solar control materials and more particularly, selective glazing are part of the solutions proposed to reduc...

The high potential of [{Nb6Cli12}La6] cluster-based building blocks as near-infrared radiation blockers for energy saving applications is exposed in the present paper (i = inner edge-bridging ligand, a = apical ligand of the Nb6; L = H2O and/or Cl). To do so, a combined experimental and theoretical investigation of edge-bridged [{Nb6Cli12}Cla6-x(H2...

We developed a new environment-sensing device based on the opto-ionic-electronic phenomena of an octahedral molybdenum metal (Mo6) cluster. When the Mo6 cluster is electrochemically deposited on a transparent electrode in an organic solvent containing a trace amount of water, the water permeates the deposited film. During the process, some ligand s...

The comparison between NiFe2O4 (co-precipitation) and NiFe2O4@SiO2 (co-precipitation and microemulsion) ferrite nanoparticles in their as-received and annealed form is presented. The structural characterization revealed the gradual crystallization of as-received samples induced by thermal treatment. The existence of cubic inverse spinel ferrite str...

A metal cluster-based inorganic–organic hybrid compound, (TBA) 2 [Mo 6 Br ⁱ 8 Br a 6 ], exhibits a reentrant transition of the crystallographic structure and photoluminescence property in a low temperature range.

The Mo6 cluster which has the great optical properties and chemical activity because of their unique electronic structure have been attracted attention in many fields such as phosphor and photocatalyst. However, the Mo6 cluster it’s hard to recycling which limited its industry application because of its such small nanoscale. Immobilizing the Mo6 cl...

A novel heterogeneous catalytic nanomaterial based on a molybdenum cluster-based halide (MC) and a single-layered copper hydroxynitrate (CHN) was first prepared by colloidal processing under ambient conditions. The results of the elemental composition and crystalline pattern indicated that CHN was comprehensively synthesized with the support of the...

Edge-bridged halide tantalum clusters based on the {Ta6Br12}4+ core have been the topic of many physicostructural investigations both in solution and in the solid-state. Despite a large number of studies, the fundamental correlations between compositions, local symmetry, electronic structures of [{Ta6Bri12}La6]m+/n- cluster units (L = Br or H2O, in...

The tunable photo-induced electronic property of the Cs2[{Mo6Brⁱ8}Bra6] and Br2[{Ta6Brⁱ12}(H2O)a6] octahedral metal cluster-based compounds was characterized by the zeta potential measurement upon irradiation by ultraviolet–visible (UV–Vis) light. The enhancement of the electronic charge on the surface of the [{Mo6Brⁱ8}Bra6]²⁻ cluster-based anion c...

Recrystallization of Cs2[Mo6X14] (X=Cl, Br) was examined using typical organic solvents, i. e., methanol (CH3OH), acetone (CH3COCH3) and dichloromethane (CH2Cl2) in order to modify crystal structures and optoelectronic properties by promoting purity or inducing insertion of guest molecules. To this context, we performed recrystallization in solvent...

The fight against infective microorganisms is becoming a worldwide priority due to serious concerns about the rising numbers of drug-resistant pathogenic bacteria. In this context, the inactivation of pathogens by singlet oxygen, O2(1Δg), produced by photosensitizers upon light irradiation has become an attractive strategy to combat drug-resistant...

A new layered double hydroxide (LDH)-based nanocomposite functionalized with an octahedral molybdenum atom cluster (MC) exhibiting prominent photoactive and oxidation properties was synthesized. ZnAl LDH and ZnAl LDH intercalated dodecyl sulfate compounds (abbreviated as LDH-1 and LDH-2 respectively) were prepared by the co-precipitation method in...

A novel UV-Vis photodetector consisting of an octahedral molybdenum cluster-functionalized Zn2Al layered double hydroxide (LDH) has been successfully synthesized by co-precipitation and delamination methods under ambient conditions. The electrophoretic deposition process has been used as a low cost, fast, and effective method to fabricate thin and...

Transition metal nitrides (TMN) form a class of materials with unique physical and chemical properties. Among them, molybdenum nitrides are mainly used as high performance magnets or catalysts for a wide range of reactions. This work aims at developing innovative syntheses to prepare nanostructured TMN from metallic clusters for heterogeneous catal...

The nanoparticle-based material technology has recently opened a new heat shielding material generation for window applications such as aerogel, vacuum insulation panel or nanospace materials. Aiming to prepare a nanospace-based heat insulation material functionalized with an ultraviolet (UV) absorbent, the Mo6 cluster-deposited hollow silica nanop...

Transparent optical thin films for energy saving application have recently gained substantial prominence for functional window processes. In this study, highly visible transparent nanocomposite films with ultraviolet (UV) and near-infrared (NIR) blocking capabilities are reported. Such nanocomposites films, prepared by electrophoretic deposition on...

Engineered oxide nanoparticles have appeared as a highly promising tool for soil remediation. However, their behaviour under complex environmental exposures (i.e. in natural soils) remains poorly understood and a relevant issue to complete their risk assessments. Prior using iron oxide nanoparticles in soil remediation scenarios, it is crucial to e...

The comprehensive study of the Ni0.5Zn0.5Fe2O4 ferrite nanopowder crystallized in the inverse spinel structure and synthesized by co-precipitation method is presented. The distribution of Fe3+ cations among tetrahedral and octahedral sites was confirmed. The microstructural investigations revealed the presence of ultrafine grained structure with an...

This work explores the potentiality of Mo6 clusters as new inorganic sensitizers with amphoteric properties for photoelectronic applications being non-toxic and stable. It reports on the design of photoelectrodes by electrophoretic deposition (EPD) of molybdenum octahedral metal cluster iodide (CMI) onto mesoporous TiO2 and NiO layers before being...

Transparent optical thin films have recently attracted a growing interest for functional window applications. In this study, highly visible transparent nanocomposite films with ultraviolet (UV)-near-infrared (NIR)-blocking capabilities are reported. Such films, composed of Mo6 and Nb6 octahedral metal atom clusters (MC) and polymethylmethacrylate p...

Metal clusters Nanoparticles are obtained by a simple solvent shifting procedure called the Ouzo effect. Remarkably, the assembly of [{Mo6Br8}L6]2- (L=Br- or NCS-) cluster units can be directed into nanomarbles...

This review paper summarizes our very recent works on the synthesis of multifunctional transparent nanocomposite thin films or coatings based on metal atom clusters by an electrophoretic deposition (EPD) process. Eight different octahedral atom clusters with niobium, molybdenum or tantalum as metallic cores were used to prepare highly transparent t...

Hexanuclear tantalum bromide cluster units [{Ta6Brⁱ12}La6] (i = inner, a = apical, L = ligand OH or H2O) are embedded into SiO2 nanoparticles by a reverse microemulsion (RM) based method. [{Ta6Brⁱ12}Bra2 (H2O)a4]·nH2O (noted TBH) and tetraethyl orthosilicate (TEOS) are used as the starting cluster compound and the precursor of SiO2, respectively. T...

Context: as a kind of non-metal oxide SiO2 NPs have been extensively used in biomedicine, pharmaceuticals and other industrial manufacturing fields, such as DNA delivery, cancer therapy… Our group had developed a method based on microemulsion process to prepare SiO2 NPs incorporating photonic or magnetic nanocrystals and luminescent nanosized inor...

Nanoparticle (NP) stability in aqueous environments is dependent upon many parameters including environmental conditions, NP concentrations as well as NP intrinsic characteristics. In this study, the effects of pH and surface modifications on the colloidal and chemical stabilities of nanosized magnetite (Fe3O4), maghemite (γ-Fe2O3) and hematite (α-...

Hollow nanocapsules (named Hybridosomes®) possessing a polymer/nanoparticles shell were used to covalently construct hybrid films in a one-pot fashion. Alkyne bearing organic/inorganic Hybridosomes® were reticulated with azide bearing homobifunctional polyethyleneglycol (PEG) linkers, by using an electro-click reaction on F-SnO2 (FTO) electrodes. T...

NO3-type Zn/Al layered double hydroxides were synthesized by co-precipitation method. The interlayers of the layered double hydroxides were highly expanded by intercalating laurate ions by ion exchange to get it easier to distinguish each layer of the layered double hydroxides by high-resolution transmission electron microscopy observation. Direct...

The electronic and structural characteristics of the octahedral molybdenum cluster-based ternary compound, Cs2[Mo6Cl14], were investigated based on density functional theory (DFT) and subsequent comparisons with experimentally observed results. The geometry optimization and band structure calculations of Cs2[Mo6Cl14] were performed using three stan...

The crystallization of a high-purity hexamolybdenum cluster chloride, Cs2[Mo6Cl14], was investigated with the aim of improving its intrinsic properties, including optical properties. In particular, we used the hydrophilicities of alcoholic solvents to purify Cs2[Mo6Cl14] by dehydration. The precursor, trigonal Cs2[Mo6Cl14] with water impurities, or...

This study reports the first integration of inorganic tantalum octahedral metal atom clusters in multifunctional nanocomposite coating materials and devices for window technology and energy saving applications. [Ta6Bri12]n+ (n = 2, 3 or 4) cluster-based high visible transparent UV and NIR filters are realized. Green and brown colored films are fabr...

Thin and transparent Mo6 cluster films with significant optical properties were prepared on indium tin oxide (ITO)-coated glass plates from the suspension of Cs2Mo6Br14 cluster precursors dispersed in methyl-ethyl-ketone (MEK) by an electrophoretic deposition (EPD) process. Two kinds of polydimethylsiloxanes (PDMS); i.e., KF-96L-1.5CS and KF-96L-2C...

The first integration by solution deposition process of tantalum octahedral clusters in multifunctional nanocomposite materials and devices for smart window is investigated in this study. Two [Ta6Bri12]n+ cluster cores-based high transparent visible UV and NIR filters are realized. Films are fabricated by incorporation of clusters in a polymer matr...

We report the photoluminescence (PL) and cathodoluminescence (CL) properties of face-capped [Mo6Xⁱ8La6]²⁻ (X = Cl, Br, I; L = organic or inorganic ligands) cluster units. We show that the emission of Mo6 metal atom clusters depends not only on the nature of X and L ligands bound to the cluster and counter-cations, but also on the excitation source....

The electronic and crystal structures of Cs2[Mo6X14] (X = Cl, Br, I) cluster-based compounds were investigated by density functional theory (DFT) simulations and experimental methods such as powder X-ray diffraction, ultraviolet-visible spectroscopy, and X-ray photoemission spectroscopy (XPS). The experimentally determined lattice parameters were i...

Among the solution deposition techniques, electrophoretic deposition (EPD) is a fairly rapid and low cost two-step process well-known for ceramic shaping and conductive surface coating. Recently we have reported the fabrication of transparent inorganic thin film composed of octahedral molybdenum clusters and shown that the stabilization of the clus...

We report here the synthesis, the crystal structure and the luminescent properties of the new cluster compounds Cs2Mo6Cl14·H2O and Cs2Mo6Br14·H2O. Single-crystal X-ray diffraction performed on Cs2Mo6Cl14·H2O indicates that the compound crystallizes in the monoclinic space group C2/c with refined cell parameters a = 19.578 Å, b = 15.151 Å, c = 9.347...

Bioimaging and cell labeling using red or near infrared phosphors emitting in the "therapeutic window" of biological tissues have recently become some of the most active research fields in modern medical diagnostics. However, because organic and inorganic autofluorophores are omnipresent in nature, very often the background signal from fluorochrome...

Thin films of octahedral molybdenum metal clusters (Mo6) were fabricated on indium tin oxide (ITO) glass slides by the electrophoretic deposition (EPD) technique. The solubility of the Cs2Mo6Br14 cluster compounds, which are composed of [Mo6Bri8Bra6]2− units associated with two cesium cations, in different solvents was investigated in order to achi...

The laser irradiation’s effects on γ-Fe2O3 maghemite of 4±1 nm diameter nanocrystals synthesized by co-precipitation and dispersed into an amorphous silica matrix by sol-gel methods have been investigated as function of Fe oxide mass fraction. The structural properties of γ-Fe2O3 phase were carefully examined by X-ray diffraction and transmission e...

The development of phosphor devices free of heavy metal or rare earth elements is an important issue for environmental reasons and energy efficiency. Different mixtures of ZnO nanocrystals with Cs 2 Mo 6 I 8 (OOC 2 F 5) 6 cluster compound (CMIF) dispersed into polyvinylpyrrolidone matrix have been prepared by very simple and low cost solution chemi...

We herein report the structure-property relationships of the octahedral molybdenum metal cluster compound, Cs2[Mo6Cl14]. Using purified samples, we attempted to determine if Cs2[Mo6Cl14] possesses crystalline polarity. Heat treatment was performed prior to characterization to remove impurities, as X-ray powder diffraction and Fourier transformation...

The first step of the integration of molybdenum clusters as new absorbers in all inorganic solar cells inspired from perovskite cells have been investigated via the fabrication of first cluster sensitized solar cells. The latter have been realized from the photoelectrodes obtained by chemisorption of the clusters on TiO2 and NiO films (respectively...

Nitrogen doped zinc oxide (ZnO) nanoparticles have been synthesized using a colloidal route and low temperature nitridation process. Based on these results, 200 nm thick transparent ZnO thin films have been prepared by dip-coating on SiO2 substrate from a ZnO colloidal solution. Zinc peroxide (ZnO2) thin film was then obtained after the chemical co...

As part of the risk evaluation before potential applications of nanomaterials, phytotoxicity of newly designed multifunctional silica nanoparticles (CMB@SiO2, average diameter of 47 nm) and their components, i.e., molybdenum octahedral cluster bromide units (CMB, 1 nm) and SiO2 nanoparticles (nSiO2, 29 nm), has been studied using photosynthetic Ara...

The encapsulation of ZnO nanoparticles (5 nm) coated by cyanobiphenyl units by the sol-gel technique leads to spherical ZnO@SiO2 nanoparticles displaying blue emission under UV excitation.

Heteronuclear lanthanide-based coordination polymers are microcrystalline powders, the luminescence properties of which can be precisely tuned by judicious choice of the rare-earth ions. In this study, we demonstrate that such materials can also be obtained as stable solutions of nanoparticles in non-toxic polyols. Bulk powders of the formula [Ln2-...

The foundation of nanoscience is that the properties of materials change as a function of their physical dimensions, and nanotechnology exploits this premise by applying selected property modifications for a specific benefit. However, to investigate the fate and effect of the engineered nanoparticles on toxic metal (TM) mobility, the analytical lim...

Perovskites are mixed-metal oxides that are attracting much scientific and application interest owing to their low price, adaptability, and thermal stability, which often depend on bulk and surface characteristics. These materials have been extensively explored for their catalytic, electrical, magnetic, and optical properties. They are promising ca...

For the first time, hexanuclear complexes with general chemical formula [Ln6O(OH)8(NO3)6(H2O)n](2+) with n = 12 for Ln = Sm-Lu and Y and n = 14 for Ln = Pr and Nd were stabilized as nanoaggregates in ethylene glycol (EG). These unprecedented nanoaggregates were structurally characterized by (89)Y and (1)H NMR spectroscopy, UV-vis absorption and lum...

Recently, Nanoarchitectonics has been introduced as a new concept that refers to a technology system for arranging nanoscale structural units in a required architecture. Multifunctional properties are achieved by a combination of several materials in a well-defined architecture. In the frame of this concept, composite nanoarchitectures represent a...

Zinc oxide is a material of great interest exhibiting pigmental, photocatalytic, piezoelectric, antibacterial, or varistor properties that have already been developed in many different fields of industry. Still novel applications emerge in various domains but they often require the preliminary stabilization of a p-type ZnO counterpart to the natura...

We investigated the influence of the coating of maghemite nanoparticles (NPs) with oleic acid and oleylamine molecules on the thermal stability of maghemite and on the γ → α-Fe2O3 phase transformation. The uncoated maghemite NPs were synthetized by co-precipitation and the coated NPs by thermal decomposition of organometallic precursors. The morpho...

The design and realization of high-quality bandpass optical filters are often very difficult tasks due to the strong correlation of the optical index of dielectric thin films to their final thickness, as observed in many industrial deposition processes. We report on the optimization of complex optical filters in the visible and NIR spectral ranges...

At the occasion of the fiftieth birthday of the introduction of the term ‘metal atom cluster’ by F. A. Cotton in inorganic chemistry, it is the good time to make a review on the advances in the engineering of molecular assemblies and nanomaterials based on octahedral Re6 metal atom clusters. The latter exhibit unique intrinsic structural and physic...