Promising Perspectives on the Use of Fullerenes as Efficient Containers for Beryllium Atoms

The possibility of using fullerenes as containers for toxic beryllium atoms is studied by a multi-scale approach in which first-principles and classical molecular dynamics simulations are combined. By studying the energetics, electronic and spectroscopic properties of Be-fullerene systems and by simulating their interaction at finite temperature in vacuo and in representative biological environments it is concluded that: i) Be endohedral complexes can be obtained by implanting Be atoms at energies >2.3 eV that is consistent with laser implantation technologies; ii) it is in principle possible to distinguish stable endohedral complexes from metastable exohedral ones by optical absorption, suggesting that optical spectroscopy can be a valuable a non-destructive technique to assist the synthesis and the control of implanted films iii) the Be-endohedral complexes are long-lived and thermodynamically stable and can confine beryllium both in vacuo and in aqueous solution; iv) Be@C60 complexes are likely unable to penetrate the selectivity filters of a prototypical protein showing that fullerene prevents undesired interactions with biomolecules and toxicity effects of Be2+ related to replacement of the Ca2+. Overall, these results provide an assessment on the possibility to encapsulate Be atoms into fullerenes by ion implantation to synthesize inert and highly stable and safe molecular containers for toxic beryllium radionuclides. Great opportunities are expected for the realization and application of Be-C60 complexes to nanotechnology and nanomedicine with particularly appealing perspectives in the field of neutron capture therapy of cancer

Ag/In lead‐free double perovskites

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UNITO E L’AFRICA. Progetti, iniziative, relazioni per una strategia di Ateneo

Questo documento raccoglie gli esiti di un percorso avviato quasi due anni fa, con una prima richiesta di segnalazione di progetti volta a costruire una mappatura di iniziative in, per e con attori e territori africani che coinvolgevano in vari modi l’Ateneo, con le sue strutture e personale, tra ricerca, didattica, terza missione e cooperazione allo sviluppo

Ion Migration‐Induced Amorphization and Phase Segregation as a Degradation Mechanism in Planar Perovskite Solar Cells

The operation of halide perovskite optoelectronic devices, including solar cells and LEDs, is strongly influenced by the mobility of ions comprising the crystal structure. This peculiarity is particularly true when considering the long‐term stability of devices. A detailed understanding of the ion migration‐driven degradation pathways is critical to design effective stabilization strategies. Nonetheless, despite substantial research in this first decade of perovskite photovoltaics, the long‐term effects of ion migration remain elusive due to the complex chemistry of lead halide perovskites. By linking materials chemistry to device optoelectronics, this study highlights that electrical bias‐induced perovskite amorphization and phase segregation is a crucial degradation mechanism in planar mixed halide perovskite solar cells. Depending on the biasing potential and the injected charge, halide segregation occurs, forming crystalline iodide‐rich domains, which govern light emission and participate in light absorption and photocurrent generation. Additionally, the loss of crystallinity limits charge collection efficiency and eventually degrades the device performance

Un microscopio computazionale per lo studio di materiali innovativi per il fotovoltaico del futuro

The importance of using photovoltaics (PVs) to obtain clean and reliable energy hasbeen widely recognized. The scientific research on new PV materials is crucial to identifynew approaches to the concept of solar energy conversion and to increase the photonversionefficiency. Among the different approaches for PV, the quantum dot (QD) solarcell is one of the most promising. A single layer QD consists of a distribution ofnanocrystals embedded into an amorphous dielectric matrix. It is in principle possibleto affect the optoelectronic properties of QD layers by controlling the morphology ofthe nanograins. The complex atomic scale structure of such materials makes it quitedifficult to predict theoretically their optoelectronic properties. The theoretical challengeis two-fold; on the one hand, it is necessary to generate large scale atomistic models;on the other hand, the corresponding electronic properties must be computed over alarge number of atoms. While the first issue can be coped with large-scale moleculardynamics (MD) simulations, the second issue is a major computational bottleneck andit requires a class of advanced algorithms for the electronic structure calculations inwhich the computational workload scales linearly with the number of atoms. Within acollaboration among CASPUR and the SLACS (Sardinian Laboratory for Computationalmaterials science) we have implemented a new numerical method to investigate theoptoelectronic properties of silicon based QD layers. By using such a theoretical frameworkit is possible to assist the design of new efficient materials for PV