Time-domain ab initio modeling of excitation dynamics in quantum dots

The review discusses the results of ab initio time-dependent density functional theory and non-adiabatic molecular dynamics simulations of photoinduced dynamics of charges, excitons, plasmons, and phonons in semiconductor and metallic quantum dots (QDs). The simulations create an explicit time-domain representation of the excited-state processes, including elastic and inelastic electron–phonon scattering, multiple exciton generation, fission, and recombination. These nonequilibrium phenomena control the optical and electronic properties of QDs. Our approach can account for QD size and shape, as well as chemical details of QD structure, such as dopants, defects, core/shell regions, surface ligands, and unsaturated bonds. Each of these variations significantly alters the properties of photoexcited QDs. The insights reported in this review provide a comprehensive understanding of the excited-state dynamics in QDs and suggest new ways of controlling the photo-induced processes. The design principles that follow, guide development of photovoltaic cells, electronic and spintronic devices, biological labels, and other systems rooted in the unique physical and chemical properties of nanoscale materials

Charge-Transfer Luminescence in a Molecular Donor-Acceptor Complex: Computational Insights

Donor-acceptor molecular complexes are a popular class of materials utilizing charge-transfer states for practical applications. A recent class of donor-acceptor dyads based on the fluorescent BODIPY functionalized with triphenylamine (TPA) shows the peculiar property of dual fluorescence. It is hypothesized that instead of the sensitized charge-transfer state being optically dark, it provides an additional bright radiative pathway. Here we use time-dependent density functional theory to characterize the energetic alignment of excitonic and charge-transfer states in a BODIPY-TPA molecular complex. We observe that using a long-range exchange corrected functional in combination with state-specific solvation scheme gives a qualitatively correct alignment of the exciton and charge-transfer states and an enhancement in oscillator strength for the equilibrium solvated charge-transfer state, in agreement with experiment. This work provides rationalization of charge-transfer state emission and provides a foundation to explore charge-transfer using ab initio excited-state nonadiabatic dynamics.Fil: Forde, Aaron. No especifíca;Fil: Freixas Lemus, Victor Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Fernández Alberti, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Neukirch, Amanda J.. No especifíca;Fil: Tretiak, Sergei. No especifíca

Recent Advances in Modeling Laser-Driven EUV Light Source Plasmas for Nanolithography

The light source in extreme ultraviolet (EUV) lithography tools is a hot and dense laser-driven plasma. We will give an overview of our recent work on modeling the radiative and expansion characteristics of these plasmas

Recent Advances in Modeling Laser-Driven EUV Light Source Plasmas for Nanolithography

The light source in extreme ultraviolet (EUV) lithography tools is a hot and dense laser-driven plasma. We will give an overview of our recent work on modeling the radiative and expansion characteristics of these plasmas