Publications de Julia Anna Wiktor

Oxygen Evolution at the BiVO4-Water Interface: Mechanism of the Water Dehydrogenation Reaction

Alfredo Pasquarello, Julia Anna Wiktor, Sai Lyu

We study the water dehydrogenation reaction at the BiVO4(010)-water interface by combining nudged-elastic-band calculations and electronic structure calculations at the hybrid functional level. We investigate the pathway and the kinetic barrier for the adi ...

AMER CHEMICAL SOC2022

Small Electron Polarons in CsPbBr3: Competition between Electron Localization and Delocalization

Alfredo Pasquarello, Julia Anna Wiktor, Stefano Falletta

We study the nature of excess electrons in CsPbBr3 and identify several single and double polaronic states. We emphasize the importance of proper inclusion of the self-interaction corrections for the stability of small electron polarons in this material. W ...

AMER CHEMICAL SOC2020

Finite-size corrections of defect energy levels involving ionic polarization

Alfredo Pasquarello, Julia Anna Wiktor, Stefano Falletta

We develop a scheme for finite-size corrections of vertical transition energies and single-particle energy levels involving defect states with built-in ionic polarization in supercell calculations. The method accounts on an equal footing for the screening ...

2020

Low-Frequency Dielectric Response of Tetragonal Perovskite CH3NH3PbI3

Alfredo Pasquarello, Ethan Alexandre Berger, Julia Anna Wiktor

The dielectric properties of tetragonal hybrid perovskite CH3NH3PbI3 are studied through molecular dynamics at a temperature of 300 K in the presence of a finite electric field. The high-frequency dielectric constant epsilon(infinity), is found to be 4.5 a ...

AMER CHEMICAL SOC2020

Nonempirical hybrid functionals for band gaps of inorganic metal-halide perovskites

Alfredo Pasquarello, Wei Chen, Julia Anna Wiktor, Thomas Bischoff

Nonempirical hybrid functionals are investigated for band-gap predictions of inorganic metal-halide perovskites belonging to the class CsBX3, with B = Ge, Sn, Pb and X = Cl, Br, I. We consider both global and range-separated hybrid functionals and determin ...

2019

Electron and Hole Polarons at the BiVO4-Water Interface

Alfredo Pasquarello, Julia Anna Wiktor

We determine the transition levels of electron and hole polarons at the BiVO4-water interface through thermodynamic integration within a hybrid functional scheme, thereby accounting for the liquid nature of the water component. The electron polaron is foun ...

2019

pH-Dependent Surface Chemistry from First Principles: Application to the BiVO4(010)-Water Interface

Alfredo Pasquarello, Francesco Ambrosio, Julia Anna Wiktor

2018

Role of Polarons in Water Splitting: The Case of BiVO4

Alfredo Pasquarello, Francesco Ambrosio, Julia Anna Wiktor

2018

Surface Polarons Reducing Overpotentials in the Oxygen Evolution Reaction

Alfredo Pasquarello, Francesco Ambrosio, Julia Anna Wiktor, Patrick Gono

2018

Mechanism suppressing charge recombination at iodine defects in CH3NH3PbI3 by polaron formation

Alfredo Pasquarello, Francesco Ambrosio, Julia Anna Wiktor

Metal-halide perovskites exhibit high efficiencies in photovoltaic applications and low recombination rates, despite the high concentrations of intrinsic defects. We here study the hole trapping at the negative iodine interstitial, which corresponds to the ...

Royal Society of Chemistry2018

Sizable Excitonic Effects Undermining the Photocatalytic Efficiency of beta-Cu2V2O7

Alfredo Pasquarello, Mariateresa Scarongella, Raffaella Buonsanti, Julia Anna Wiktor, Igor Reshetnyak, Michal Stanislaw Strach

Copper vanadates have been proposed as promising photoanodes for water-splitting photoelectrochemical cells, but their performance has recently been shown to be severely limited. To understand this behavior, we study the electronic structure and the optica ...

2018

pH-Dependent Catalytic Reaction Pathway for Water Splitting at the BiVO4−Water Interface from the Band Alignment

Alfredo Pasquarello, Francesco Ambrosio, Julia Anna Wiktor

We align the band edges of BiVO4 at the interface with liquid water by combining advanced electronic-structure calculations, molecular dynamics simulations, and a computational hydrogen electrode. After accounting for spin–orbit coupling and thermal and nu ...

2018

Origin of low electron-hole recombination rate in metal halide perovskites

Alfredo Pasquarello, Francesco Ambrosio, Julia Anna Wiktor

To address the slow recombination of photogenerated charges in tetragonal CH 3 NH 3 PbI 3 , the evolution of extra electrons and holes is simulated through advanced ab initio molecular dynamics. We show that the localization of the charge carriers and thei ...

2018

First-principles calculations of momentum distributions of annihilating electron-positron pairs in defects in UO2

Julia Anna Wiktor

We performed first-principles calculations of the momentum distributions of annihilating electron-positron pairs in vacancies in uranium dioxide. Full atomic relaxation effects (due to both electronic and positronic forces) were taken into account and self ...

Iop Publishing Ltd2017

Comprehensive modeling of the band gap and absorption spectrum of BiVO4

Alfredo Pasquarello, Francesco Ambrosio, Julia Anna Wiktor, Igor Reshetnyak

We present first-principles calculations of the electronic structure of BiVO4 at various levels of theory. In the calculations, we take into account a series of effects that affect the band gap, i.e., spin-orbit coupling, electron-hole interaction, nuclear ...

2017

Note: Assessment of the SCAN+rVV10 functional for the structure of liquid water

Alfredo Pasquarello, Francesco Ambrosio, Julia Anna Wiktor

American Institute of Physics2017

Partial Molar Volumes of Aqua Ions from First Principles

Alfredo Pasquarello, Julia Anna Wiktor

Partial molar volumes of ions in water solution are calculated through pressures obtained from ab initio molecular dynamics simulations. The correct definition of pressure in charged systems subject to periodic boundary conditions requires access to the va ...

Amer Chemical Soc2017

Predictive Determination of Band Gaps of Inorganic Halide Perovskites

Alfredo Pasquarello, Ursula Röthlisberger, Julia Anna Wiktor

We carry out first-principles calculations of band gaps of cubic inorganic perovskites belonging to the class CsBX3, with B = Pb, Sn and X = Cl, Br, I. We use the quasi particle self-consistent GW method with efficient vertex corrections to calculate the e ...

2017

Fully self-consistent calculations of momentum distributions of annihilating electron-positron pairs in SiC

Julia Anna Wiktor

We performed calculations of momentum distributions of annihilating electron-positron pairs in various fully relaxed vacancy defects in SiC. We used self-consistent two-component density functional theory schemes to find the electronic and positronic densi ...

Amer Physical Soc2016

Absolute deformation potentials of two-dimensional materials

Alfredo Pasquarello, Julia Anna Wiktor

We present ab initio calculations of uniaxial absolute deformation potentials of the valence and the conduction bands in monolayer MoS2, MoSe2, WS2, WSe2, h-BN, and phosphorene. Calculations are performed using both semilocal and hybrid functionals. The ab ...

Amer Physical Soc2016