International audienceThe integration by a solution deposition process of tantalum octahedral clusters in multifunctional nanocomposite materials and devices for smart windows is investigated for the first time in this study. Two [Ta6Bri 12]n+ cluster core-based highly transparent visible UV and NIR filters are realized. Films are fabricated by incorporation of clusters in a polymer matrix and coating them on an ITO substrate. The electrochromic cell consists of a Ta6-based electrolyte inserted between two transparent conductive electrodes. In both cases, the modification of the absorption properties in the visible and NIR spectral range is possible by altering and controlling the oxidation state of the tantalum cluster. The stabilization of reduced [Ta6Bri 12]2+ or oxidized [Ta6Bri 12]3+/4+ species leads to green-emerald or slight brown filters having a slight or a strong red-NIR absorption respectively. Their efficiency in energy saving is estimated by the determination of figures of merit and color coordinates. This highlights that [Ta6Bri 12]n+-based composites are promising absorbers for energy saving applications. © 2017 The Royal Society of Chemistry

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 Cs2Mo6I8(OOC2F5)6 cluster compound (CMIF) dispersed into polyvinylpyrrolidone matrix have been prepared by very simple and low cost solution chemistry. The resulting solutions have been used to fabricate highly transparent and luminescent films by dip coating free of heavy metal or rare earth elements. The luminescence properties of solution and dip-coated films were investigated. The luminescence of such a system is strongly dependent on the ratios between ZnO and CMIF amounts, the excitation wavelength and the nature of the system. By varying these two parameters (ratio and wavelength), a large variety of colors, from blue to red as well as white, can be achieved. In addition, differences in the luminescence properties have been observed between solutions and thin films as well as changes of CMIF emission band maximum wavelength. This may suggest some possible interactions between the different luminophore centers, such as energy transfer or ligands exchange on the Mo6 clusters.