Electronic excitations in light absorbers for photoelectrochemical energy conversion: first principles calculations based on many body perturbation theory

Abstract

We describe state of the art methods for the calculation of electronic excitations in solids and molecules, based on many body perturbation theory, and we discuss some applications of these methods to the study of band edges and absorption processes in representative materials used as photoelectrodes for water splitting.

Optoelectronic properties ofTa3N5: A joint theoretical and experimental study

“…21 for oxides and some nitrides (starting from Kohn-Sham orbitals obtained with gradient corrected functionals), we estimate the error introduced by the lack of self-consistency to be smaller than 10% for the G 0 W 0 value of the electronic gap of Ta 3 N 5 . The optical absorption spectra were obtained by solving the Bethe-Salpeter Equation (BSE), [8][9][10] starting from our G 0 W 0 results and employing the double-grid method for k-point sampling. 22 …”

“…5,6 Aiming to fully characterize the opto-electronic properties of Ta 3 N 5 and to understand possible reasons for the limited photocurrent, we have performed a joint experimental and ab initio theoretical study of Ta 3 N 5 . Ab initio calculations were carried out using density functional theory 7 (with local, semi-local, and hybrid exchange-correlation functionals) and many-body perturbation theory (at the G 0 W 0 level), 8,9 and the optical absorption spectra were computed by solving the Bethe-Salpeter Equation (BSE). 8,10 We also used ab initio calculations to compute the effective masses of holes and electrons, and gain insight into the carrier transport properties of Ta 3 N 5 .…”

Optical properties of tungsten trioxide from first-principles calculations

“…In this paper we report ab initio calculations of the fundamental and optical gap of γ-WO 3 , and of its absorption spectrum, carried out using many body perturbation theory(MBPT) [23,24]. We carried out calculations of the band structure within the G 0 W 0 approximation [25][26][27] and we solved the Bethe-Salpeter Equation (BSE) [23,24] to obtain the optical spectra, using the method of Refs.…”

“…We carried out calculations of the band structure within the G 0 W 0 approximation [25][26][27] and we solved the Bethe-Salpeter Equation (BSE) [23,24] to obtain the optical spectra, using the method of Refs. [28,29].…”

Communication: Electronic structure of the solvated chloride anion from first principles molecular dynamics

“…From a theoretical standpoint, only few interpretations or predictions 15,[17][18][19][20] of photoelectron spectra appeared in the literature; indeed, the microscopic description of aqueous solutions from first principles remains a challenging task, both from a theoretical and computational standpoint, and especially so in the case of anions, whose electronic structure is in general more complex than that of cations. 7,21,22 In this paper, we consider a chloride anion in aqueous solution and report an analysis of its electronic properties based on first principles molecular dynamics (MD) using several levels of theory; these include semi-local (Perdew-BurkeErnzerhof (PBE) 23,24 ) and hybrid (PBE0 25 ) functionals and many body perturbation theory (MBPT) 26 within the G 0 W 0 approximation. 27,28 To the best of our knowledge, these are the first calculations of the electronic properties of a solvated ion in water using ab initio MD with hybrid functionals and MBPT.…”