4,234 research outputs found
ADRENALINE - hAliDe peRovskites sEqueNtiAL deposItioN mEchanism (by ab initio
No full textThe objective of the ADRENALINE project is to study the atomistic mechanism, energetics and kinetics of the sequential deposition method of (hybrid) lead halide perovskites for 3rd generation solar cells and optoelectronics applications. The project is based on ab initio rare event simulations of the key step of the process, the intercalation of the cation A+ (me- thylammonium, CH3NH3+, formamidinium, (NH2)2CH+, and Cesium cation, Cs+) and anion X- (I-, Br- and Cl-) and reorganization of the intermediate product into the final one. The PI of the ADRENALINE project is an expert of rare event techniques who have contribute to de- velop some of the methods used in the field. Dr. Meloni has already applied rare event tech- niques to processes occurring in lead halide perovskites. The project will be developed in parallel to an experimental activity performed in the group of Prof Graetzel
Combining Rare Events Techniques: Phase Change in Si Nanoparticles
No full textWe describe a combined Restrained MD/Parallel Tempering approach to study the difference in free energy as a function of a set of collective variables between two states in presence of metastabilities in the manifold orthogonal to the one spanned by the chosen collective variables. We illustrate the method by an extended study of the relative stability of the amorphous vs crystalline Si nanoparticles embedded in a-SiO2 of size ranging between 0.8 and 1.8 nm as a function of temperature [S. Orlandini, S. Meloni, and L. Colombo in Phys. Rev. B 83:235303, 2011]. The results show that the method permits to get over the hidden metastabilities. Finally, we try to identify the missing collective variables from the Restrained MD/Parallel Tempering trajectories and analyze whether the collective variable used to control the amorphous-to-crystalline transition is adequate to describe the mechanism of crystallization of some of the nanoparticles considered
Materiali porosi per l’energy storage, energy scavenging e altre applicazioni technologiche
No full textIl tema di questa ricerca è lo studio dei principi chimico-fisici controllanti l’intrusione/estrusione di liquidi in metal-organic framework, MOF, idrofobi (Fig1). Attraverso i MOF idrofobi sarà possibile realizzare dispositivi per l’accumulo, dissipazione e riciclo di energia dispersa nell’ambiente, con applicazioni che vanno dalla produzione di “energia verde” (accumulo e riciclo) all’ingegneria aerospaziale (dissipazione)
PROCEED - UPSTREAM INTEGRATION OF 112CO2 WITH GREEN METHANE PRODUCTION
No full text112CO2 focuses on productions of H2 from COx-free, low temperature, catalytic decomposition of methane. The PROCEED project focuses on the complementary aspect of producing green methane as a hydrogen carrier beyond the limitations of present technologies. In particular, we aim to learn how the catalyst, supposed to be supported/nickel-based, interacts with carbon and hydrogen to produce methane using advanced atomistic simulations beyond the state-of-the-art techniques used in the literature. We expect that the results of this low TRL project will spring extensive and higher TRL research to develop an innovative technology to make it possible to extensively use carbon as a green hydrogen carrier. An analysis of recent projects based on standard technologies reveals that carbon can serve as a green hydrogen carrier worth ~5 million tons of hydrogen a year within 2045, corresponding, e.g., to more than 10% the primary energy demand of Germany
PROVING-IL: PeROVskite Interface eNgineerinG with Ionic Liquids
No full text3rd generation photovoltaics will further revolutionize the field of energy enabling a distributed energy harvesting. To achieve this goal, new low-cost, high-efficiency and robust materials are needed. Halide perovskites are key materials that attracted significant attention over the last 5-10 years thanks to their high efficiency: > 23% of the harvested light is converted in electric current in the best perovskite solar cells.
To further enhance the efficiency, reliability and stability of perovskite solar cells several shortcomings must be solved, one being the relatively poor electron extraction at the TiO2/perovskite contact in planar solar cells, which are simpler to fabricate and thus commercially more promising. One of the strategies recently proposed to address this issue is the introduction of a layer of ionic liquids between the TiO2 and perovskite films. The objective of the PROVING-IL project is to use advanced simulation techniques to understand the microstructure and electronic transport properties of the TiO2/ionic liquid/perovskite heterostructure that lead to the sizable enhancement of performance measured in experiments. The final objective of the PROVING-IL project is to identify design principles to optimize the chemical composition of ionic liquids that can bring to the fabrication of high-performance planar perovskite solar cells
Perovskiti di alogenuri: controllo della formazione e migrazione dei difetti di punto per l'ottimizzazione dell'efficienza fotovoltaica
No full textStudio della migrazione dei difetti di punto in Halide perovskite
PINPOINT - Perovskite-Inspired materials-based iNdoor PhotovOltaics for powering the Internet of Things.
No full textInternet of things (IoT) is a booming technology, and its autonomous powering is key to allow this technological transition. Present powering approaches, mostly based on batteries, are neither energetically convenient, nor reliable and efficient: the continuous check of their charge level and “healt” hampers the adoption and expansion of IoT. “Self-powering” would be possible through indoor photovoltaics (IPV), combined with energy storage, for those devices operating h24, including in dark conditions. IPV is less developed than its outdoor counterpart (OPV) and new efficient, ecofriendly, cheap, and easy to fabricate materials are sought after. They must be free of toxic elements as one expects billions of powerpack for IoT operating in the future, which must be disposed at the end of their life without complex and expensive treatments.
Traditional materials, like silicon, are not optimal for IPV as their performance in high photon energy/low intensity IPV conditions are relatively poor. Novel materials, like lead-halide perovskites, contain toxic elements, which make them risky. In the PINPOINT project, we propose to use perovskite-inspired materials (PIM) that are safe, easy to fabricate, potentially made of non-critical elements for powering IoT devices. We consider Cs2AgBiBr3, BiOI and Cs3Sb2I9-xClx, which have been already investigated for OPV. Cs2AgBiBr3, containing the critical Ag element, is here considered mainly as a reference material, being the most studied PIM in OPV. All these materials have an indoor spectroscopic limited maximum efficiency (i-SLME) of 40-50%, i.e., they can potentially convert about half of the photons illuminating PV cells into electric current. Despite their potential, present efficiencies of these PIMs in both OPV and IPV conditions is 2-5%, leaving room for a significant improvement should the reasons for poor performance be identified.
In the PINPOINT project, we will use a tight coupled experimental/theoretical, interdisciplinary (physics, chemistry, engineering) approach i) to identify the bottlenecks limiting the efficiency of the selected PIM materials, ii) to identify their structural characteristics (defects, gran boundaries, interfaces, etc) determining these bottlenecks, iii) to identify and improve the depositions strategies and parameters to push the PCE of PIM-based IPV toward their i-SLME. In pursuing its immediate objectives, the PINPOINT projects will contribute to identify novel principles to develop defect-tolerant wide bandgap materials beyond antibonding top of the valence band orbital criterion, discovered through metal-halide perovskites.
In PINPOINT, we plan actions directed to the dissemination of scientific results and consolidation of the multidisciplinary community at the core of the project as well as communication campaigns to engage the civil society and the local communities of three partner institutions, to make them sensible to energy-related theme
Processi e strutture di sistemi di fase solida studiati con metodi di dinamica molecolare e diffrazione di raggi X
No full textMOF to prevent degradation of hybrid halide perovskites
No full textHybrid Perovskite, HP, emerged as a competitive, low-cost, highly-efficient photovoltaic technology. Its adoption, however, is prevented by the poor stability of this material under the action of stressing agents, e.g., humidity. Here, I propose to investigate the use of metal-organic frameworks as multi-functional self-assembling protecting layer, which can also capture environmentally harming metals, e.g., lead, which can be released during the years of operation of a solar panel
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