Shaping and patterning of bulk materials (SPS) and surface coating

Spark plasma sintering (SPS); Densification; Light absorption & emission; Energy; Dip- & Spin- coating; Magnetron; PLD; Clusters.

Valorization of solid state materials needs not only their synthesis but also their shapping and patterning. Depending on targeted physical properties, shaping can vary from bulk materials obtained by sintering processes to dispersion in matrices in order to coat an active or passive layer. Control of materials synthesis and shaping processes are mandatory to develop industrial partnership.


The SPS sintering method
Spark Plasma Sintering (SPS) became an essential technique in a solid-state chemistry laboratory for shaping of the materials.  Installed in 2013 in our Institute, our FCT HP-D-10 apparatus is used to sinter sputtering or pulsed laser deposition targets (e.g. of piezoelectric materials precursors such as K0,5Na0,5NbO3, or of MxMo6S8 sulphides), for in situ syntheses of MxMo6S8 (M = Cu, Ni, Zn) Chevrel phases, to densify thermoelectric materials (skutterudites, silicides, sulphides such as germanite, renierite,…), fuel cell electrodes (Ruddlesden-Popper quaternary oxides), photovoltaic materials (Cu2ZnSn(SxSe1-x)4 for example) for (photo)electrochemical characterizations, nuclear fuels (uranium silicides and carbides) and correlated electron systems (transition metal phosphides).

J. Nucl. Mater., 2021, 543, 152541
J. Alloys Compd., 2020, 827, 154341
Mat. Tod. Chem., 2020, 16, 100223
J. Am. Cer. Soc., 2020, 103, 2328
J. Non-Cryst. Solids, 2019, 514, 116
Mater. Res. Bull., 2021, MRB-D-20-01504R1, just accepted


Surface Coating
As part of collaborative activities with IRL LINK (NIMS/Tsukuba/Japan), CSM, in partnership with Saint-Gobain and in collaboration with the CTI team, is developing research on the use of metal clusters as functional molecular bricks, for example for blocking radiation UV and IR solar. Several components are being developed in parallel, from i) the prediction of optical properties of clusters by quantum calculations, ii) their synthesis by solid-state chemistry to iii) their incorporation into composite materials. The combined experimental and theoretical studies have made it possible to establish the relationships between the composition of the clusters, their degree of oxidation and the effects of solvents on the optical properties. Electro-chromatic systems have also been produced in this context. The choice fell on octahedral clusters of niobium and / or tantalum which, after synthesis by solid state chemistry techniques at high temperature, were incorporated by chemistry in solution in hybrid organic / inorganic matrices. The deposition techniques were then optimized until the production of demonstrators. This work is actually carried out in the frame of the ANR PRCE CLIMATE.

Picture: (a) UV-vis-NIR spectra (without reference) of ITO substrate and Ta6@PVP@ITO glass coating film. (b) UV-vis-NIR spectra (with the PVP@glass reference) and photographs of green and brown Ta6@PVP@glass films.

J. Mater. Chem. C, 2017, 5, 8160-8167
J. Mater. Chem. C, 2017, 5, 10477-10484


Toward 'all-inorganic' solar cells: inorganic Molybdenum Clusters as Light-Harvester in All Inorganic Solar Cells: A Proof of Concept. Another aspect of this activity concerns the use of clusters as light collectors for the realization of "all-inorganic" solar cells. This work involves collaborations with IRL LINK as well as IMN of Nantes. Dye solar cells integrating cluster-based photoelectrodes were produced. Photo-anodes and photo-cathodes were obtained separately by dipping chemisorption or by electrophoresis deposition of AxMo6Xi8La6 cluster compounds on TiO2 and NiO films respectively. These photoelectrodes were then integrated into n-type and p-type dye solar cells. It has been demonstrated in these photoelectrodes that transfers of electrons or photo-induced holes occur from the cluster to n-type or p-type semiconductors.

Picture: (a) Photographs of Cs2Mo6I14 powder and of the solution after dissolution in ethanol. Molar absorptivity spectrum of the molybdenum cluster iodide in ethanol. (b) Photographs of TiO2 and NiO films before and after chemisorption of the molybdenum cluster iodide. (c) Coloration of a TiO2 film according the soak time in the cluster solution. (d) Photograph of a final TiO2/cluster/cobalt complex‐based cell.

ChemistrySelect, 2016, 1, 2284-2289
Electrochimica Acta, 2019, 317, 737-745