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Inorganic perovskite nanocrystals (NCs) have shown good potential as an emerging semiconducting building block owing to their excellent optoelectronic properties. However, despite extensive studies on their structure-dependent optical properties, they still suffer severely from chemical and phase instabilities in ambient conditions. Here, we report a facile method for the synthesis of mixed halide inorganic perovskite NCs based on recrystallization in an antisolvent mixture in an ambient atmosphere, at room temperature. We introduced an alcohol-derivative solvent, as a secondary antisolvent in the solvent mixture, which crystallizes at room temperature. This mediates and facilitates the perovskite crystallization, leading to a high chemical yield and stability. We demonstrate that this secondary antisolvent establishes intermolecular interactions with lead halide salt, which successfully stabilizes the γ-dark phase of perovskite by encapsulating NCs in a solution and thin film. This allows us to produce concentrated NC solutions with a photoluminescence quantum yield of 70%. Finally, we fabricate CsPbI2Br NCs (optical bandgap 1.88 eV) solar cells, which showed a stabilized photovoltaic performance in ambient conditions, without encapsulation, showing a Vocof 1.32 V.

Nanostructured manganese oxide thin films with different crystallinity and nanomorphology were synthesized by pulsed laser deposition (PLD) in oxygen gas. Through grazing-incidence X-ray diffraction during postdeposition thermal annealing in oxidizing (air) or inert (N2flux) atmospheres, phase changes, crystallization onsets, and orientation effects were evaluated between room temperature and 600 °C, revealing a significant impact of growth conditions and nanoscale morphology on the X-ray patterns. Compact nanocrystalline Mn3O4films underwent first crystallization improvement between 300 and 485 °C accompanied by unit cell shrinkage, then phase transition to α-Mn2O3above 500 °C in an oxidizing environment. In contrast, during annealing under N2flux, crystalline Mn3O4was stable up to 600 °C, maintaining the preferential orientation promoted by PLD. Similarly, nanoporous amorphous MnO2films crystallized to α-Mn2O3(>480 °C) and Mn3O4(∼385 °C) in oxidizing and inert atmospheres, respectively; however, the amorphous porous morphology led to poorer crystallinity and an isotropic, powder-like crystal orientation. Quantitative analysis of structural parameters in the whole temperature range and microscopic and Raman analyses complemented the results. These findings shed light on the structural stability and nanoscale design achievable by PLD, followed by suitable annealing, of materials relevant for several technological applications.

Plasma assisted CVD is now an established technique for the growth of a variety of dielectrics and semiconductors. The versatility of an in-house developed direct-current (dc) microplasma deposition system is demonstrated here for the growth of a wide range of carbon-based materials. Diamond, nanodiamond, nanocrystalline graphite, single-wall carbon nanotubes, and few-layer graphene have been deposited using the same dc microplasma deposition system using 0.5% CH4/H2gas feed, but changing only the substrate temperature (in the range 500–1150 °C) and the total pressure (0.3–200 Torr). The different structures have been characterized by scanning electron microscopy and micro-Raman spectroscopy. The experimental data have been interpreted from a thermodynamic point of view by applying a nonequilibrium nondissipative model. Nonequilibrium phase diagrams are presented and compared to the experimental data to provide a wide-ranging interpretation scenario.

Metal matrix nanocomposites have been produced by powder metallurgy route. Al and nanoAl2O3 powders were grinded through high energy ball milling. Then, the composite powders were sintered by Equal Channel Angular Pressing (ECAP). 12 ECAP passes were carried out in order to improve the dispersion of the hard particles. SEM analysis was performed to investigate the distribution of the ceramic nanoparticles within the matrix. Hardness tests were executed to evaluate the mechanical behavior of the nanocomposites. Finally, mechanical strength values obtained by numerical models were compared with those estimated from hardness measurements. High energy ball milling followed by ECAP process revealed to be a suitable route for the production of metal matrix composites reinforced with well dispersed nanoparticles.

Surface irradiation of AISI 301 with ultra-short linearly polarized pulses between 247 fs and 7 ps resulted in laser induced periodic surface structures (LIPSS). Scanning electron microscope micrographs taken after the laser treatment show the formation of sub-micrometer sized arrays of nearly parallel ripples slightly differing from each other, depending on the specific treatment adopted. Static contact angle data indicate that LIPSS induce a marked hydrophobic behavior of the treated surfaces. The friction coefficient of laser treated and pristine AISI 301 surfaces gliding on compact snow was compared to that of ultra-high molecular weight polyethylene. The friction coefficients of the laser treated samples are intermediate between those of bare AISI 301 and of UHMWPE. The changes in contact angle and surface morphology of the samples after extensive tribometer tests were tested to investigate the durability of LIPSS.

Equal-channel angular pressing (ECAP) can produce ultrafine grain structures in metals. The processing can also dissolve second phases through mechanical alloying effects over the equilibrium solubility of alloying elements. Therefore, one can enhance mechanical properties by combining ECAP and subsequent precipitation treatment by proper aging. In this preliminary study, an AZ80 Mg alloy was investigated. The original extruded bars were subjected to ECAP at 473 K for 4 passes to achieve a significant grain refinement down to the submicrometric regime. The possibility of exploiting the aging effect to improve mechanical strength of the alloy was studied by the following two different methods. The first method consisted of ECAP processing the samples followed by aging. The second method consisted of performing a solution treatment prior to ECAP processing and then the final aging of the samples. Micro-hardness measurements and microstructure analyses showed that reprecipitation of the Mg17Al12 phase can occur during warm temperature ECAP and aging in the AZ80 alloy at grain cores in a more finely dispersed form. This precipitation behavior can potentially generate a significant contribution to the strength of the UFG alloy.