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The formation and stability of (arene)Cr(CO) 3 species inside two highly porous materials;UiO-66, which is a recently synthesized metal-organic framework, and a cross-linked poly(styrene-codivinylbenzene) resin;are investigated in detail by means of complementary spectroscopic techniques and theoretical calculations. In particular, Fourier transform infrared (FT-IR), ultravioletvisible (UV-vis), and X-ray absorption near-edge structure (XANES) spectroscopies, coupled with theoretical calculations, allow the formation of the (arene)Cr(CO) 3 species to be followed in situ, starting from the Cr(CO) 6 precursor, monitoring the changes in the vibrational and electronic properties of the materials. EXAFS spectroscopy gives the structural evidence of the functionalized unities. Finally, the photoinduced reactivity of Cr(CO) 3 in UiO-66 is also explored, by following the substitution of one CO ligand with a N 2 molecule. The overall presented data would become the starting point for the development of a systematic procedure for investigating functionalized porous matrices.

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Perovskite solar cells (PSCs) are an emerging photovoltaic technology that promises to offer facile and efficient solar power generation to meet future energy needs. PSCs have received considerable attention in recent years, have attained power conversion efficiencies (PCEs) over 22%, and are a promising candidate to potentially replace the current photovoltaic technology. The emergence of PSCs has revolutionized photovoltaic research and development because of their high efficiencies, inherent flexibility, the diversity of materials/synthetic methods that can be employed to manufacture them, and the various possible device architectures. Further optimization of material compositions and device architectures will help further improve efficiency and device stability. Moreover, the search for new functional materials will allow for mitigation of the existing limitations of PSCs. This review covers the recently developed advanced techniques and research trends related to this emerging photovoltaic technology, with a focus on the diversity of functional materials used for the various layers of PSC devices, novel PSC architectures, methods that increase overall cell efficiency, and substrates that allow for enhanced device flexibility.

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The synthesis and the morphological transformations of pure and silver loaded titanate nanotubes into anatase titania nanostructures under relatively mild temperatures (500°C) have been discussed. At first, it will be shown that the transformation of titanate into titanium oxide leads to the formation of TiO 2 particles, and then the role of the silver, in affecting morphology, crystallinity, and optical properties of the nanostructures, is highlighted. Morphology and structure of the titanate precursor and of the formed TiO 2 particles (both pure or silver loaded) have been investigated by means of Brunauer-Emmett-Teller and powder X-ray diffraction analyses, high resolution transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. Surface and optical properties have been explored by means of Fourier transform infrared (FTIR) and ultraviolet-visible diffuse reflectance spectroscopies. With regard to the vibrational properties of the obtained materials, the comparison of FTIR features of adsorbed CO on pure and silver exchanged titanates, with respect to pure and silver loaded TiO 2 , have been reported for the first time. It will be shown that all the materials (as prepared, either in the hydrogen or in the silver exchanged form and those obtained after thermal treatments) show better properties than the commercial TiO 2 precursor and in general than those obtained by solid state reactions (P25), in terms of specific surface area and porosity.

The field of nanotechnology has been gaining great success due to its potential in developing new generations of nanoscale materials with unprecedented properties and enhanced biological responses. This is particularly exciting using nanofibers, as their mechanical and topographic characteristics can approach those found in naturally occurring biological materials. Electrospinning is a key technique to manufacture ultrafine fibers and fiber meshes with multifunctional features, such as piezoelectricity, to be available on a smaller length scale, thus comparable to subcellular scale, which makes their use increasingly appealing for biomedical applications. These include biocompatible fiber-based devices as smart scaffolds, biosensors, energy harvesters and nanogenerators for the human body. This paper provides a comprehensive review of current studies focused on the fabrication of ultrafine polymeric and ceramic piezoelectric fibers specifically designed for, or with the potential to be translated toward, biomedical applications. It provides an applicative and technical overview of the biocompatible piezoelectric fibers, with actual and potential applications, an understanding of the electrospinning process, and the properties of nanostructured fibrous materials, including the available modeling approaches. Ultimately, this This article is protected by copyright. All rights reserved. 3 review aims at enabling a future vision on the impact of these nanomaterials as stimuli-responsive devices in the human body.

Recently, it has been shown that Engelhard titanosilicate (ETS-10), a crystalline microporous titanosilicate, is an inverse-shape-selective photocatalyst. The main drawback in the extensive use of this material was its band gap value, located in the UV, that does not allow the use of solar light. In this work, we succeed in shifting the ETS-10 light absorption down to the visible region of the electromagnetic spectrum by introducing Ag + cations inside the ETS-10 channels. Thermal-, chemical-, and UVphototreatments have been applied to Ag-ETS-10 to tune, in a controlled and progressive way, the aggregation of isolated Ag + counterions into metal nanoclusters of increasing nuclearity. This is a direct means to tune the frequency of silver nanoparticle plasmon resonance and thus the light absorption properties of the material. It is further reported that transformation of isolated Ag + ions into aggregated Ag 0 nanoclusters is almost reversible. Cycles of H 2 -chemical reduction/O 2 -chemical oxidation and of UV-photoreduction/vis-photo-oxidation are reported. UV-vis, Ag K-edge extended X-ray absorption fine structure (EXAFS), and Fourier transform infrared (FTIR) spectroscopy of adsorbed CO are the main techniques used to monitor the evolution of the silver aggregation along the different reduction/ oxidation treatments.