Nanoarchitectonic photoelectrodes built‐up from octahedral metal atom cluster‐based building blocks for solar cell applications

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SYNTHESIS AND CHARACTERIZATION OF NANOCOMPOSITES COATING BASED ON INORGANIC OCTAHEDRAL CLUSTER UNITS FABRICATED BY ELECTROPHORETIC DEPOSITION PROCESS

Composite nanoarchitectures represent a new class of nanostructured entities that integrate various dissimilar nanoscale building blocks including clusters, particles, wires and films [1]. The heterogeneous composite nanostructured materials are composed by definition of multi-(nano)components, each tailored to address different requirements. As one of the nanocomponents, nanometer sized transition metal clusters (\u3c2 nm), which consist of less than a few dozens of metal atoms, could be defined as a link between atom and nanoparticle [2-7]. In this presentation, the first preparation of functional thin films based on octahedral molybdenum metal clusters deposited on ITO glass substrate by EPD will be discussed in detail [8]. More generally, we will focus on our recent results on thin films for optical and energy applications [9-10]. References [1] R. Liu et al., Chem. Commun., 2011, 47, 1384 [2] F. A. Cotton, Inorg. Chem., 1964, 3, 1217 [3] A. Perrin et al., C. R. Chimie, 2012, 15, 815 [4] Y. Luab et al., Chem. Soc. Rev., 2012, 41, 3594 [5] V. Fedorov, J. Clust. Sci., 2015, 26, 3 [6] S. Cordier et al., J. Inorg. Organomet. Polym., 2015, 25 189 [7] F. Grasset et al., Adv. Mater., 2008, 20, 1710 [8] T.K.N Nguyen et al., ECS J. Solid State Sci. Technol., 2016, (10) R178-R186 [9] T. G. Truong et al., Sci. Technol. Adv. Mat., 2016, 17(1), 443 [10] A. Renaud et al., ChemistrySelect, 2016, 1, 228

Solvent-Templated Electrodeposition of Mesoporous Nickel Oxide Layers for Solar Cell Applications

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P-type transition metal carbodiimides MNCN (M = Ni, Mn)

International audienceOver the last decade, p-type semiconductors (SC) have known a renewed interest. Indeed these materials may have potential applications for light-emitting diodes, transistors, solar cells, etc. Since the stabilization of the first p-type semiconductor CuAlO2 with a delafossite structure type (A+B3+O2) by H. Kawazoe in 1997, many p-type semiconductors with the same structure have been reported such as CuGaO2, CuCrO2, CuScO2… Recently, X. Liu & al have reported the synthesis and the structure determination of a new family of materials: the transition metal carbodiimides MNCN (with M = Mn → Cu). These materials adopt a structure type related to the delafossite, formed by a divalent transition metal and NCN2-anion. We report here the synthesis and the microstructural characterization of two transition metal carbodiimides MnNCN and NiNCN. Impedance measurements demonstrate the p-type conductivity of these materials.</br

Iridium(iii) dipyridylamine complexes: synthesis, characterization and catalytic activities in photoredox reactions

International audienceTwo new series of cyclometalated iridium(III) complexes bearing a dipyridylamine as the N^N ligand have been prepared and fully characterized. After investigation of their photophysical properties, their catalytic activities have been evaluated in a model photoredox reaction and compared with the commercially available [Ir(ppy)2 (dtbbpy)][PF6] comple

Nanoarchitectonics of Metal Atom Cluster-Based Building Blocks Applied to the Engineering of Photoelectrodes for Solar Cells

International audienceThis study deals with the nanoarchitectonic concept applied to the design of photoelectrodes built on two types of cluster core building blocks, namely, {Re6S8i} and {Re6Se8i}. The effect of the nature of the metal/ligand on photoinduced conductivity properties is thus investigated through an in-depth photoelectrochemical study and it is rationalized by the establishment of an energy diagram using a set of complementary optical (ultraviolet-vis-near infrared), electrochemical and spectroscopic (X-ray photoelectron spectroscopy) characterization techniques. The optical and electronic properties of {Re(6)Q(8)(i)}-based films (Q = S or Se) are drastically dependent on the composition. The sulfide-based photoelectrodes exhibit ambipolar behavior with an n-type domination whereas the selenide-based photoelectrodes have a p-type semiconducting behavior. Such electronic properties can be exalted by increasing the interactions between the cluster building blocks by heating. The design of mixed {Re(6)Q(8)(i)}-based photoelectrodes combining the two n-{Re6S8i} and p-{Re6Se8i} cluster core-based building blocks is explored. The physical properties of the heterostructures can be tuned by controlling the {Re6S8i}:{Re6Se8i} ratio and the interaction between the clusters. The creation of such nanoarchitectonic p-n junctions allows the optimization of the photocurrents generated by increasing the separated charge state lifetime that turns out to be attractive for solar cell applications

Effect of an Aromatic Sulfonate Ligand on the Photovoltaic Performance of Molybdenum Cluster-Sensitized Solar Cells

International audienceThe photovoltaic performance of molybdenum cluster-sensitized solar cells has been explored with the challenge of enhancing their efficiency due to the low charge transfer efficiency. Aromatic sulfonate ligands (NS = naphthalene 2,6-disulfonate = –OSO2–C10H6–SO3–) were now used for the functionalization of the {Mo6Ii8} cluster cores. The new functional [Mo6I8iI3a(H2O)2a(NS)a] cluster unit exhibits enhanced photophysical and photoelectrochemical properties compared to other homologues based on the {Mo6I8i} cluster cores. In greater detail, the role of the NS functional groups was beneficially emphasized for the improved oxidation stability of the cluster in a redox mediator, adjusting the emission lifetime to a suitable range for fast electron injection, and accelerating the charge transport process. The best as-synthesized Mo6 cluster-based solar cell resulted in a stable photocurrent of 2.38 mA cm–2 with a fill factor of 0.63 and the power conversion efficiency of 0.97% under an AM 1.5 illumination, a two times’ enhancement in comparison to the reference iodide Mo6 cluster-based cell (0.52%). Specific attention focused on the increase of the power conversion efficiency up to 1.18% after 330 s and then reached the saturation trend. The enhanced charge transfer of the metal cluster complex was obtained from facile modifications of the functional apical ligands that result in advantageous photophysical and electrochemical characteristics, specializing in optoelectronic devices. This study provides the general methodology and knowledge for the next improvement of the photovoltaic efficiency of the Mo6 cluster-based sensitized solar cells

A review on functional nanoarchitectonics nanocomposites based on octahedral metal atom clusters (Nb-6, Mo-6, Ta-6, W-6, Re-6): inorganic 0D and 2D powders and films

International audienceThis review is dedicated to various functional nanoarchitectonic nanocomposites based on molecular octahedral metal atom clusters (Nb-6, Mo-6, Ta-6, W-6, Re-6). Powder and film nanocomposites with two-dimensional, one-dimensional and zero-dimensional morphologies are presented, as well as film matrices from organic polymers to inorganic layered oxides. The high potential and synergetic effects of these nanocomposites for biotechnology applications, photovoltaic, solar control, catalytic, photonic and sensor applications are demonstrated. This review also provides a basic level of understanding how nanocomposites are characterized and processed using different techniques and methods. The main objective of this review would be to provide guiding significance for the design of new high-performance nanocomposites based on transition metal atom clusters