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Erokhin V.,CNR Institute of Materials for Electronics and Magnetism
AIP Conference Proceedings | Year: 2015

Three applications of molymeris materials for the unconventional computing are considered, namely, organic memristive devices, nanoengineered polymeric capsules and hybrid systems polymer - slime mold. © 2015 AIP Publishing LLC.

Bianchi M.,University of Bologna | De Pascale A.,University of Bologna | Melino F.,CNR Institute of Materials for Electronics and Magnetism
Applied Energy | Year: 2013

The aim of this paper is the evaluation of the profitability of micro-CHP systems for residential application. An integrated CHP system composed of a prime mover, an Electric Energy Storage system, a thermal storage system and an auxiliary boiler has been considered. The study has been carried out taking into account a particular electrochemical storage system which requires also thermal energy, during its operation, for a better exploitation of the residual heat discharged by the prime mover. The prime mover could be a conventional Internal Combustion Engine or also an innovative system, such as fuel cell or organic Rankine cycle.An investigation of this integrated CHP system has been carried out, by means of an in-house developed calculation code, performing a thermo-economic analysis. This paper provides useful results, in order to define the optimum sizing of components of the integrated CHP system under investigation; the developed code allows also to evaluate the profitability and the primary energy saving with respect to the separate production of electricity and heat. © 2013 Elsevier Ltd.

Tonezzer M.,CNR Institute of Materials for Electronics and Magnetism | Iannotta S.,CNR Institute of Materials for Electronics and Magnetism
Talanta | Year: 2014

In this work we have grown particular zinc oxide two-dimensional nanostructures which are essentially a series of hexagonal very thin sheets. The hexagonal wurtzite crystal structure gives them their peculiar shape, whose dimensions are few microns wide, with a thickness in the order of 25 nm. Such kind of nanostructure, grown by thermal oxidation of evaporated metallic zinc on a silica substrate, has been used to fabricate conductometric gas sensors, investigated then for hydrogen gas detection. The "depletion layer sensing mechanism" is clarified, explaining how the geometrical factors of one- and two-dimensional nanostructures affect their sensing parameters. The comparison with one-dimensional ZnO nanowires based structures shows that two-dimensional nanostructures are ideal for gas sensing, due to their tiny thickness, which is comparable to the depletion-layer thickness, and their large cross-section, which increases the base current, thus lowering the limit of detection. The response to H2 has been found good even to sub-ppm concentrations, with response and recovery times shorter than 18 s in the whole range of H 2 concentrations investigated (500 ppb-10 ppm). The limit of detection has been found around 200 ppb for H2 gas even at relatively low working temperature (175 C). © 2014 Elsevier B.V.

Panizon E.,CNR Institute of Materials for Electronics and Magnetism | Bochicchio D.,CNR Institute of Materials for Electronics and Magnetism | Rossi G.,CNR Institute of Materials for Electronics and Magnetism | Ferrando R.,CNR Institute of Materials for Electronics and Magnetism
Chemistry of Materials | Year: 2014

Researchers conducted investigations to demonstrate that nanoparticle synthesis techniques have made significant advances toward the goal of producing nanoalloys with atomically precise composition. Gas phase methodologies such as atomic layer deposition can be employed to synthesize supported bimetallic nanoparticles with atomically precise control. Solution based techniques have shown that it is possible to dope passivated Pd or Au nanoparticles with metal impurities. Atomically controlled doping of metal nanoparticles is crucial for a variety of tailored applications in catalysis, magnetism, and optics. Researchers demonstrate through examples on how small changes in composition, achieved by introducing a small percentage of impurities in a matrix nanoparticle can have significant effects on its structure for large nanoparticle sizes, containing up to a few thousand atoms.

Bosi M.,CNR Institute of Materials for Electronics and Magnetism | Attolini G.,CNR Institute of Materials for Electronics and Magnetism
Progress in Crystal Growth and Characterization of Materials | Year: 2010

This paper reviews the most important properties of germanium, gives an insight into the newer techniques and technology for the growth of epitaxial Ge thin layers and focuses on some applications of this material, with a special emphasis on recent achievements in electronics and photovoltaics. We will highlight the recent development of Ge research and will give an account of the most important Ge applications that emerged in the last two decades. Germanium is a key material in modern material science and society: it is used as a dopant in fiber optic glasses and in semiconductor devices, both in activating conduction in layers and also as a substrate for III-V epitaxy. Ge is also widely used in infrared (IR) detection and imaging and as a polymerization catalyst for polyethylene terephthalate (PET). Moreover, high-speed electronics for cell phone communications relies heavily on SiGe alloys. Ge electronics is nowadays gaining new interest because of the enhanced electronic properties of this material compared to standard silicon devices, but the lack of a suitable gate oxide still limits its development. High efficiency solar cells, mainly for space use but also for terrestrial solar concentration have surpassed 40% efficiency and Ge has a lead role in achieving this goal. The main focus of the paper is on Ge epitaxy. Since epitaxy starts from the surface of the substrate, different studies on substrate pre-epitaxy, surface analysis and preparations are reviewed, covering the most common substrates for Ge deposition such as Ge, Si and GaAs. The most used Ge precursors such as GeH 4 and GeCl 4 are described, but several novel precursors, mostly metal-organic, have recently been developed and are becoming more common in epitaxial Ge deposition. Epitaxial growth of Ge by means of the most common methods, including Chemical Vapour Deposition and Molecular Beam Epitaxy is discussed, along with some recent advances in Ge deposition, such as Atomic Layer Deposition and Low Energy Plasma-Enhanced Chemical Vapour Deposition. Several Ge applications are finally discussed, with the aim of providing insights into the potential of this material for the development of novel devices that are able to surpass the current limits of standard device design. Ge in microelectronics is becoming more and more important, thanks to the possibilities offered by bandgap engineering of strained SiGe/Si. However, lack of a good Ge oxide is posing several problems in device improvement. In the field of photovoltaics Ge is mainly used as a substrate for high efficiency III-V solar cells and for the development of thermophotovoltaic devices instead of the most expensive and scarcer GaSb. In this field, Ge epitaxy is very rare but the development of an epitaxial Ge process may help in developing new solar cells concepts and to improve the efficiency of thermophotovoltaic converters. Ge may play a role even in new spintronics devices, since a GeMn alloy was found to have a higher Curie temperature than GaAsMn. © 2010 Elsevier Ltd. All rights reserved.

Bosi M.,CNR Institute of Materials for Electronics and Magnetism
RSC Advances | Year: 2015

Nanosheet materials such as graphene, boron nitride and transition metal dichalcogenides have gathered a lot of interest in recent years thanks to their outstanding properties and promises for future technology, energy generation and post-CMOS device concepts. Amongst this class of materials transition metal dichalcogenides based on molybdenum, tungsten, sulfur and selenium gathered a lot attention because of their semiconducting properties and the possibility to be synthesized by bottom up techniques. Vapour phase processes such as chemical vapour deposition permit to produce high quality layers and to precisely control their thickness. In order to target industrial applications of transition metal dichalcogenides it is important to develop synthesis methods that allow to scale up wafer size, and eventually integrate them with other technologically important materials. This review will cover all the currently proposed methods for the bottom up synthesis of transition metal dichalcogenides from the vapour phase, with particular emphasis on the precursors available and on the most common semiconductor techniques like metal organic chemical vapour deposition and atomic layer epitaxy. A summary of the most common characterization technique is included and an overview of the growth issues that still limit the application of TMD is given. © The Royal Society of Chemistry 2015.

Bochicchio D.,CNR Institute of Materials for Electronics and Magnetism | Ferrando R.,CNR Institute of Materials for Electronics and Magnetism
European Physical Journal D | Year: 2012

The structure and thermal stability of AgCu core-shell chiral nanoparticles is investigated by means of global optimization searches and molecular-dynamics simulations within an atomistic model. The most energetically stable structures are searched for depending on the number N Ag of A g atoms in the outer shell. Both icosahedral and C 5 symmetry structures are considered. The thermal stability of the structures is studied for magic sizes and compositions by analyzing the melting transition. It is found that chiral shells are the most favourable in a wide range of N Ag and that the structures present a notable thermal stability. © The Author(s) 2012.

Erokhin V.,CNR Institute of Materials for Electronics and Magnetism
International Journal of Unconventional Computing | Year: 2013

Qualitative illustration of the difference between "adult" and "baby" learning, previously observed for stochastic 3D networks of matrices of block co-polymers, conducting polymers and gold nanoparticles, is presented. The model assumes the formation of stable multi-pathway channels in the case of "baby" learning and dynamic equilibrium of single signal pathways in the case of "adult" learning. ©2013 Old City Publishing, Inc.

Bochicchio D.,CNR Institute of Materials for Electronics and Magnetism | Ferrando R.,CNR Institute of Materials for Electronics and Magnetism
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

Bimetallic nanoparticles (often known as nanoalloys) with core-shell arrangement are of special interest in several applications, such as in optics, catalysis, magnetism, and biomedicine. Despite wide interest in applications, the physical factors stabilizing the structures of these nanoparticles are still unclear to a great extent, especially for what concerns the relationship between geometric structure and chemical ordering patterns. Here global-optimization searches are performed in order to single out the most stable chemical ordering patterns corresponding to the most important geometric structures, for a series of weakly miscible systems, including AgCu, AgNi, AgCo, and AuCo. The calculations show that (i) the overall geometric structure of the nanoalloy and the shape and placement of its inner core are strictly correlated; (ii) centered cores can be obtained in icosahedral nanoparticles but not in crystalline or decahedral ones, in which asymmetric quasi-Janus morphologies form; (iii) in icosahedral nanoparticles, when the core exceeds a critical size, a new type of morphological instability develops, making the core asymmetric and extending it towards the nanoparticle surface; (iv) multicenter patterns can be obtained in polyicosahedral nanoalloys. Analogies and differences between the instability of the core in icosahedral nanoalloys and the Stranski-Krastanov instability occurring in thin-film growth are discussed. All these issues are crucial for designing strategies to achieve effective coatings of the cores. © 2013 American Physical Society.

Barbieri E.S.,University of Ferrara | Melino F.,CNR Institute of Materials for Electronics and Magnetism | Morini M.,University of Ferrara
Applied Energy | Year: 2012

In recent years, cogeneration systems have gained increasing attention especially when dealing with distributed generation for residential buildings. One of the main problems with using cogenerative systems in residential building applications is that the demand for heat and electricity is not synchronized. For this reason, when the combined heat and power system operates during electricity peak hours (i.e. the rate of the electricity is higher), it could be profitable to store the heat in order to satisfy delayed demands. This paper presents a model for the calculation of the profitability of micro combined heat and power systems for residential building applications. The model takes into account hourly demands calculated by means of monthly and daily load profiles for heat and electricity. The system under consideration is composed of a CHP system, an auxiliary boiler and a heat-storage tank. The model is applied to a single-family dwelling in order to evaluate the effect of the size of the thermal energy storage unit on the energy and economic performance of four different prime movers (an internal combustion engine, a Stirling engine, a micro Rankine cycle and a thermophotovoltaic system). Thermal energy produced, electrical energy produced, self-consumed or exchanged with the grid, consumed natural gas, as well as differential cash flow with respect to separate generation and payback period are presented. The effect of the size of the thermal energy storage proves to be not linear with respect to the thermal power of the prime mover. © 2012 Elsevier Ltd.

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