1,721,263 research outputs found
Nanotecnologie per catturare la luce
No full textSolar photovoltaic technology is based on the direct conversion of solar radiation power into electrical power by means of solar cells. Photovoltaics can in principle play a major role in the search for alternative energy sources, even though it is still not competitive with respect to traditional sources, e.g. based on fossil fuels. One of the most important challenges of current scientific research in this field relates to the development of new solar cell materials or new cell architectures, possibly leading to an improvement of the cell power conversion efficiency or to the parallel reduction of the energy production cost; nanotechnology plays a leading role in this framework. In this paper selected examples will be presented, which show the possible contribution of nanoscience and nanotechnology to the study and optimization of nanostructured materials for better future generation solar cells. After an introductory part presenting the different types of solar cells and highlighting the role of nanotechnology research in this field, two specific cases will be presented and discussed: the study of hierarchical titanium oxide nanostructures as photoanodes for novel dye-sensitized solar cells and the development of nanostructured transparent conducting oxides for designing multifunctional electrodes for organic or hybrid photovoltaic cells
Pulsed Laser Deposition of Nanostructured Oxides: from Clusters to Functional Films
No full textNanosecond Pulsed Laser Deposition (PLD) in a background atmosphere is a particularly versatile technique for the production of nanostructured films and surfaces. The ablation plasma plume produced by laser-matter interaction is spatially confined by the presence of a background gas, thus favouring cluster nucleation and reduction of the kinetic energy of the species impinging the substrate. This affects deposition processes and film growth mechanisms leading to the production of nanostructured systems.
Here we review our recent work focused on the development of the PLD technique for the controlled synthesis of nanostructured materials, films and surfaces with tailored properties. We show in particular that by playing with the plasma expansion dynamics, through the control of background gas type and pressure and target-to-substrate distance, a fine tuning of morphology, structure and composition can be reached for a number of metal oxides (e.g. tungsten, titanium and silver oxide). Film morphology can be varied from compact to columnar and nanostructured up to highly porous foam-like with corresponding reduction of mass density and increase of surface area. Oxide formation and stoichiometry can be controlled by ablating metal targets in a reactive background gas atmosphere. Film structure can be varied from amorphous to nanocrystalline while different oxide phases can be obtained by post-deposition thermal treatments, also depending on the starting morphology. The first stages of film growth and their relation with the size and the deposition kinetic energy of the building blocks have been investigated by in situ scanning tunnelling microscopy (STM)
Pulsed Laser Deposition of Nanostructured Oxides for Emerging Applications
No full textMetal oxides are presently employed in a number of advanced technological applications ranging from sensing, biology and energy. For such applications a good control of material properties ranging from morphological and structural to functional ones is required in order to improve or enhance the performances of the systems and the related devices. We here review our work on the Pulsed Laser Deposition of nanostructured films and surfaces showing that a fine tuning of morphology and structure can be achieved for metal oxides such as tungsten and titanium oxide. Starting from the control of the building units constituting the material we show that film morphology can be varied from compact to columnar and nanostructured to a hierarchical assembly of nanoparticles and finally to highly porous foam-like. Film structure can be varied from amorphous to nanocrystalline with the possibility to vary the oxide phase. Finally we will discuss possible applications showing that such oxides have good performances as functional materials
Time-of-flight analysis of neutral cluster beams through detection of charged particles produced by cluster impact on a channeltron
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Heavy metal element containing TeO2-based glasses for the discrete Raman fiber amplification
No full textBottom-up synthesis of nanostructured materials by Pulsed Laser Deposition: from clusters to functional films
No full textCD conference proceeding
Pulsed laser deposition of nanostructured metals and oxides: from cluster assembling to applications
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