Marco Govoni

Carrier multiplication between interacting nanocrystals for fostering silicon-based photovoltaics

Carrier multiplication is a carrier-relaxation process that results in the generation of multiple electron–hole pairs after the absorption of a single photon. Researchers have now studied the role of nanoparticle interplay on the carrier-multiplication dynamics of two interacting silicon nanocrystals for photovoltaic applications.

Self-consistent hybrid functional for condensed systems

A self-consistent scheme for determining the optimal fraction of exact exchange for full-range hybrid functionals is presented and applied to the calculation of band gaps and dielectric constants of solids. The exchange-correlation functional is defined in a similar manner to the PBE0 functional, but the mixing parameter is set equal to the inverse macroscopic dielectric function and it is determined self-consistently by computing the optimal dielectric screening. We found excellent agreement with experiments for the properties of a broad class of systems, with band gaps ranging between 0.7 and 21.7 eV and dielectric constants within 1.23 and 15.9. We propose that the eigenvalues and eigenfunctions obtained with the present self-consistent hybrid scheme may be excellent inputs for G

Large Scale GW Calculations

_0

Nonempirical range-separated hybrid functionals for solids and molecules

W

Photoelectron Spectra of Aqueous Solutions from First Principles

_0

Red-Shifted Carrier Multiplication Energy Threshold and Exciton Recycling Mechanisms in Strongly Interacting Silicon Nanocrystals

calculations.

Implementation and Validation of Fully Relativistic GW Calculations: Spin–Orbit Coupling in Molecules, Nanocrystals, and Solids

We present GW calculations of molecules, ordered and disordered solids and interfaces, which employ an efficient contour deformation technique for frequency integration and do not require the explicit evaluation of virtual electronic states nor the inversion of dielectric matrices. We also present a parallel implementation of the algorithm, which takes advantage of separable expressions of both the single particle Greens function and the screened Coulomb interaction. The method can be used starting from density functional theory calculations performed with semilocal or hybrid functionals. We applied the newly developed technique to GW calculations of systems of unprecedented size, including water/semiconductor interfaces with thousands of electrons.

Carrier multiplication in silicon nanocrystals: ab initio results.

Dielectric-dependent hybrid (DDH) functionals were recently shown to yield accurate energy gaps and dielectric constants for a wide variety of solids, at a computational cost considerably less than that of

Design of defect spins in piezoelectric aluminum nitride for solid-state hybrid quantum technologies.

\mathit{GW}

Electron affinity of liquid water

calculations. The fraction of exact exchange included in the definition of DDH functionals depends (self-consistently) on the dielectric constant of the material. Here we introduce a range-separated (RS) version of DDH functionals where short- and long-range components are matched using system-dependent, nonempirical parameters. We show that RS-DDHs yield accurate electronic properties of inorganic and organic solids, including energy gaps and absolute ionization potentials. Furthermore we show that these functionals may be generalized to finite systems.