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Cari tutti,

per sopraggiunti motivi personali, lo speaker: Dott. Edoardo Mosconi, è impossibilitato a tenere il seminario previsto nell'agenda smeet per oggi 24 novembre 2023.

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22/11/2023 09:20

Cari tutti,

vi ricordiamo l'incontro SMeet di venerdì 24 novembre 2023 alle ore 11:30, ESCLUSIVAMENTE IN PRESENZA in aula Campisano, sede IMM-CNR.

Il meeting prevede:

* Speaker: Dott. Edoardo Mosconi

* Chair: Dott. Antonino La Magna

* Titolo: Computational Modeling of Perovskite for Photovoltaics and Photocatalysis

Abstract:
Hybrid AMX3perovskites (A=Cs, CH3NH3; M=Sn, Pb; X=halide) have in the last years revolutionized the scenario of photovoltaic technologies.Despite the extremely fast progress, the materials electronic properties which are key to the photovoltaic performance are relatively little understood. We developed an effective GW method incorporating spin-orbit coupling [1] which allows us to accurately model the electronic, optical and transport properties of halide perovskites, opening the way to new materials design. In particular, the different CH3NH3SnI3and CH3NH3PbI3electronic properties are discussed in light of their exploitation for solar cells and found to be dominantly due to relativistic effects. In parallel, a series of computational simulation carried out using Car-Parrinello molecular dynamics have been performed investigating the nature of the perovskites/TiO2interface, the role of moisture in the perovskite degradation process and the effect of the defect on the device working mechanism. Finally, a series of different strategies will be reported to increase the device stability and efficiency.[2] While instability in aqueous environment has long impeded employment of metal halide perovskites for heterogeneous photocatalysis, recent reports have shown that some particular tin halide perovskites (THPs) can be water-stable and active in photocatalytic hydrogen production. To unravel the mechanistic details underlying the photocatalytic activity of THPs, we compare the reactivity of the water-stable and active DMASnBr3(DMA = dimethylammonium) perovskite against prototypical MASnI3and MASnBr3compounds (MA = methylammonium), employing advanced electronic–structure calculations. We find that the binding energy of electron polarons at the surface of THPs, driven by the conduction band energetics, is cardinal for photocatalytic hydrogen reduction.[3] In this framework, the interplay between the A-site cation and halogen is found to play a key role in defining the photoreactivity of the material by tuning the perovskite electronic energy levels. Our study, by elucidating the key steps of the reaction, may assist in development of more stable and efficient materials for photocatalytic hydrogen reduction. The overall picture of our theoretical investigations underlines a crucial role of computational investigation, casting the possibility of performing predictive modeling simulations, in which the properties of a given system are simulated even before the materials laboratory synthesis and characterization. At the same time, computer simulations are shown to offer the required atomistic insight into hitherto inaccessible experimental observables.

References:
[1] Umari, P.; Mosconi, E.; De Angelis, F. Relativistic GW Calculations on CH3NH3PbI3and CH3NH3SnI3Perovskites for Solar Cell Applications Sci. Rep. 2014,4, 4467.
[2] Yang, S.; Chen, S.; Mosconi, E.; Fang, Y.; Xiao, X.; Wang, C.; Zhou, Y.; Yu, Z.; Zhao, J.; Gao, Y.; De Angelis, F.; Huang, J. Stabilizing halide perovskite surfaces for solar cell operation with wide-bandgap lead oxysalts Science2019, 365, 473.
[3] Kaiser W.; Ricciarelli D.; Mosconi E.; Alothman A. A.; Ambrosio F.; De Angelis F. "Stability of Tin- versus Lead-Halide Perovskites: Ab Initio Molecular Dynamics Simulations of Perovskite/Water Interfaces" J. Phys. Chem. Lett., 2022, 13, 2321.

SMeet – Comitato Organizzativo
smeet[@]imm.cnr.it
Web-page: https://hq.imm.cnr.it/smeet-science-sharing-meetings