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| 2. |
- Ambrosio, Francesco, et al.
(författare)
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Charge Localization in Acene Crystals from Ab Initio Electronic Structure
- 2023
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Ingår i: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 14, s. 3343-3351
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Tidskriftsartikel (refereegranskat)abstract
- The performance of Koopmans-compliant hybrid functionals in reproducing the electronic structure of organic crystals is tested for a series of acene crystals. The calculated band gaps are found to be consistent with those achieved with the GW method at a fraction of the computational cost and in excellent accord with the experimental results at room temperature, when including the thermal renormalization. The energetics of excess holes and electrons reveals a struggle between polaronic localization and band-like delocalization. The consequences of these results on the transport properties of acene crystals are discussed.
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| 3. |
- Ambrosio, Francesco, et al.
(författare)
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Strong Hole Trapping Due to Oxygen Dimers in BiVO4: Effect on the Water Oxidation Reaction
- 2019
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Ingår i: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 10:22, s. 7113-7118
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Tidskriftsartikel (refereegranskat)abstract
- We present a study of hole bipolarons in BiVO4. We show that in the presence of two holes O-O dimers are formed, leading to strong charge trapping. While the formation of bipolarons in bulk BiVO4 requires overcoming a kinetic barrier, we find that these defects should be spontaneously formed at the surface of the material and its interface with water. Through molecular dynamics simulations, we study the effect of bipolarons on the water-splitting reaction and show that their presence may be especially beneficial in alkaline conditions.
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| 4. |
- Capobianco, Amedeo, et al.
(författare)
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Electron Localization and Mobility in Monolayer Fullerene Networks
- 2024
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Ingår i: Nano Letters. - 1530-6992 .- 1530-6984. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- The novel 2D quasi-hexagonal phase of covalently bonded fullerene molecules (qHP C60), the so-called graphullerene, has displayed far superior electron mobilities, if compared to the parent van der Waals three-dimensional crystal (vdW C60). Herein, we present a comparative study of the electronic properties of vdW and qHP C60 using state-of-the-art electronic-structure calculations and a full quantum-mechanical treatment of electron transfer. We show that both materials entail polaronic localization of electrons with similar binding energies (≈0.1 eV) and, therefore, they share the same charge transport via polaron hopping. In fact, we quantitatively reproduce the sizable increment of the electron mobility measured for qHP C60 and identify its origin in the increased electronic coupling between C60 units.
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| 5. |
- Morana, Marta, et al.
(författare)
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Cubic or Not Cubic? Combined Experimental and Computational Investigation of the Short-Range Order of Tin Halide Perovskites
- 2023
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Ingår i: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 14, s. 2178-2186
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Tidskriftsartikel (refereegranskat)abstract
- Tin-based metal halide perovskites with a composition of ASnX3 (where A= MA or FA and X = I or Br) have been investigated by means of X-ray total scattering techniques coupled to pair distribution function (PDF) analysis. These studies revealed that that none of the four perovskites has a cubic symmetry at the local scale and that a degree of increasing distortion is always present, in particular when the cation size is increased, i.e., from MA to FA, and the hardness of the anion is increased, i.e., from Br- to I-. Electronic structure calculations provided good agreement with experimental band gaps for the four perovskites when local dynamical distortions were included in the calculations. The averaged structure obtained from molecular dynamics simulations was consistent with experimental local structures determined via X-ray PDF, thus highlighting the robustness of computational modeling and strengthening the correlation between experimental and computational results.
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| 6. |
- Ouhbi, Hassan, 1989, et al.
(författare)
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Strong Electron Localization in Tin Halide Perovskites
- 2021
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Ingår i: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 12:22, s. 5339-5343
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Tidskriftsartikel (refereegranskat)abstract
- Tin halide perovskites (THPs) have been established as a lower-toxicity alternative to lead halide perovskites. In spite of the increasing interest, the behavior of photoexcited charges has not been well understood in this class of materials. We here investigate the behavior of excess electrons in a series of tin halide perovskites by employing advanced electronic-structure calculations. We first focus on CsSnBr3 and show that electron localization is favorable in this compound and that bipolaronic states are the most stable form of self-trapped electrons. We then extend the analysis to CsSnI3, CsSnCl3, MASnBr3, FASnBr3, and DMASnBr3 and show that electron bipolarons are stable in all these compounds, thus indicating that strong electron localization is recurrent in THPs.
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| 7. |
- Ricciarelli, Damiano, et al.
(författare)
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Electron bipolarons at the DMASnBr 3 –water interface: Effect on the photocatalytic hydrogen production
- 2024
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Ingår i: International Journal of Hydrogen Energy. - 0360-3199. ; 58, s. 863-871
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we report on advanced molecular dynamics simulations of the atomistic DMASnBr3–water interface, which, coupled with a grand-canonical formulation of adsorbates and defects, elucidate the surface chemistry and reactivity of this novel water-stable perovskite and highlight the role of small electron bipolarons in photocatalytic hydrogen production. We find that the extremely acidic nature of the surface Br atoms does not allow for significant adsorption of protons at the interface under charge-neutral conditions. However, when electrons are accumulated on the surface, the formation of a small electron bipolaron in the form of a Sn-Sn dimer provides the required electron localization to drive adsorption of H, which is assimilated on surface Sn atoms as hydride. Finally, we estimate a favourable alignment between the bipolaron energy level and the H+/H2 redox level, which suggests the occurrence of a feasible route for hydrogen evolution, bypassing the common reaction mechanism.
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| 8. |
- Ricciarelli, Damiano, et al.
(författare)
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Reaction Mechanism of Photocatalytic Hydrogen Production at Water/Tin Halide Perovskite Interfaces
- 2022
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 7, s. 1308-1315
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Tidskriftsartikel (refereegranskat)abstract
- 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 MASnI3 and MASnBr3 compounds (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. 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.
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| 9. |
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| 10. |
- Seferovic, Petar M., et al.
(författare)
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Sodium-glucose co-transporter 2 inhibitors in heart failure: beyond glycaemic control. A position paper of the Heart Failure Association of the European Society of Cardiology
- 2020
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Ingår i: European Journal of Heart Failure. - : WILEY. - 1388-9842 .- 1879-0844. ; 22:9, s. 1495-1503
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Tidskriftsartikel (refereegranskat)abstract
- Heart failure (HF) is common and associated with a poor prognosis, despite advances in treatment. Over the last decade cardiovascular outcome trials with sodium-glucose co-transporter 2 (SGLT2) inhibitors in patients with type 2 diabetes mellitus have demonstrated beneficial effects for three SGLT2 inhibitors (empagliflozin, canagliflozin and dapagliflozin) in reducing hospitalisations for HF. More recently, dapagliflozin reduced the risk of worsening HF or death from cardiovascular causes in patients with chronic HF with reduced left ventricular ejection fraction, with or without type 2 diabetes mellitus. A number of additional trials in HF patients with reduced and/or preserved left ventricular ejection fraction are ongoing and/or about to be reported. The present position paper summarises recent clinical trial evidence and discusses the role of SGLT2 inhibitors in the treatment of HF, pending the results of ongoing trials in different populations of patients with HF.
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| 11. |
- Österbacka, Nicklas, 1993, et al.
(författare)
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Charge Localization in Defective BiVO 4
- 2022
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 126:6, s. 2960-2970
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Tidskriftsartikel (refereegranskat)abstract
- We study the native defects in bismuth vanadate using hybrid density functional theory. We pay special attention to where excess charges localize by considering different polaronic distortions and find that charge localization has a profound effect on the local chemical environment around certain defects. In particular, oxygen dimerization may occur in the presence of acceptor defects. On the basis of Fermi level pinning due to compensation between donors and acceptors we additionally find that intrinsic p-type conductivity is difficult to achieve in BiVO4, in good agreement with experimental observations. Our results give new insights into the defect chemistry of bismuth vanadate and act as a guide for future studies on defects in complex metal oxides.
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| 12. |
- Österbacka, Nicklas, 1993, et al.
(författare)
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Spontaneous Oxygen Vacancy Ionization Enhances Water Oxidation on BiVO 4
- 2024
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Ingår i: ACS Energy Letters. - 2380-8195. ; 9:1, s. 153-158
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Tidskriftsartikel (refereegranskat)abstract
- The influence of surface oxygen vacancies on the oxygen evolution reaction on bismuth vanadate is studied using hybrid density functional theory. Our findings reveal that the neutral charge state is thermodynamically unfavorable, leading to spontaneous ionization of VO0 into VO2+. By investigating the oxygen evolution reaction mechanism on both stoichiometric and oxygen-deficient surfaces, we find that surface oxygen vacancies reduce the reaction’s thermodynamic overpotential but only when the defects are ionized. Moreover, the reaction pathway involves the formation of surface-bound peroxide and superoxide ions as intermediates. Our work provides insight into the nature of surface oxygen vacancies and shines new light on how they may enhance the photoelectrochemical properties of semiconductors.
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