Multiple exciton generation in chiral carbon nanotubes: Density functional theory based computation

Mihaylov, Deyan; Kilin, Dmitri S.

doi:10.1063/1.4997048

Cited by 14 publications

(33 citation statements)

References 63 publications

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“…For SWCNTs, the set of approximations stated above have been checked and shown to be reasonable by reproducing experimental results for the low-energy absorption peaks in (6,2), (6,5) and (10,5) SWCNTs within 5-13% error [14].…”

Section: A Microscopic Hamiltonianmentioning

confidence: 84%

“…So, here we perform calculations at the Γ point only. Previously, it has been shown that the variations in the single particle energies over the Brillouin zone is reasonably small (≈ 10%) when three unit cells have been included in the simulation instead of one [14]. For the (6,5) SWCNT only one unit cell was included due to high computational cost.…”

Section: Atomistic Modelsmentioning

confidence: 99%

“…Recently, Kryjevski et al have developed several methods for a comprehensive description of MEG in a nanosctructure using DFT-based MBPT, including exciton effects [10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…First, one uses DFT-based MBPT technique to compute exciton-to-biexciton decay and recombination rates, i.e., the rates of the inverse and direct Auger processes, respectively [10,11]. Next, one utilizes DFT software to compute phonon frequencies and normal modes, which are then used to compute one-and two-phonon exciton emission rates [14]. Finally, all these rates are incorporated into the Boltzmann transport equation (BE) which provides comprehensive nonperturbative description of time evolution of the excited state including "competition" between different relaxation channels, such as MEG, phonon-mediated relaxation, etc.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, all these rates are incorporated into the Boltzmann transport equation (BE) which provides comprehensive nonperturbative description of time evolution of the excited state including "competition" between different relaxation channels, such as MEG, phonon-mediated relaxation, etc. [14]. In particular, one can compute number of excitons generated from a single high-energy photon, which is the internal quantum efficiency (QE).…”

Section: Introductionmentioning

confidence: 99%

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Biexciton State Energies from Many-Body Perturbation Theory Based on Density Functional Theory Simulation

Mihaylov,

Kryjevski

2020

Preprint

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We develop a method for computing self-energy of a biexciton state in a semiconductor nanostructure using many-body perturbation theory (MBPT) based on the density functional theory (DFT) simulation. We compute energies of low-energy biexciton states composed of singlet excitons in the chiral single-wall carbon nanotubes (SWCNT), such as (6,2), (6,5) and (10,5). In all cases we find a small decrease in the biexciton gap: -0.045 eV in (6,2), which is 4.59% of the non-interacting biexciton gap; -0.041 eV in (6,5), which is 4.47% of the non-interacting gap and -0.036 eV in (10,5), which is 4.31%.

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Section: A Microscopic Hamiltonianmentioning

confidence: 84%

Section: Atomistic Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Biexciton State Energies from Many-Body Perturbation Theory Based on Density Functional Theory Simulation

Mihaylov,

Kryjevski

2020

Preprint

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Dynamics of Excitons in Conjugated Molecules and Organic Semiconductor Systems

Dimitriev

2022

Chem. Rev.

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The exciton, an excited electron–hole pair bound by Coulomb attraction, plays a key role in photophysics of organic molecules and drives practically important phenomena such as photoinduced mechanical motions of a molecule, photochemical conversions, energy transfer, generation of free charge carriers, etc. Its behavior in extended π-conjugated molecules and disordered organic films is very different and very rich compared with exciton behavior in inorganic semiconductor crystals. Due to the high degree of variability of organic systems themselves, the exciton not only exerts changes on molecules that carry it but undergoes its own changes during all phases of its lifetime, that is, birth, conversion and transport, and decay. The goal of this review is to give a systematic and comprehensive view on exciton behavior in π-conjugated molecules and molecular assemblies at all phases of exciton evolution with emphasis on rates typical for this dynamic picture and various consequences of the above dynamics. To uncover the rich variety of exciton behavior, details of exciton formation, exciton transport, exciton energy conversion, direct and reverse intersystem crossing, and radiative and nonradiative decay are considered in different systems, where these processes lead to or are influenced by static and dynamic disorder, charge distribution symmetry breaking, photoinduced reactions, electron and proton transfer, structural rearrangements, exciton coupling with vibrations and intermediate particles, and exciton dissociation and annihilation as well.

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Nonadiabatic Dynamics in Two-Dimensional Perovskites Assisted by Machine Learned Force Fields

Graupner,

Kilin

2024

J. Phys. Chem. C

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An exploration of the "on-the-fly" nonadiabatic couplings (NACs) for nonradiative relaxation and recombination of excited states in 2D Dion− Jacobson (DJ) lead halide perovskites (LHPs) is accelerated by a machine learning approach. Specifically, ab initio molecular dynamics (AIMD) of nanostructures composed of heavy elements is performed with the use of machine-learning forcefields (MLFFs), as implemented in the Vienna Ab initio Simulation Package (VASP). The force field parametrization is established using on-the-fly learning, which continuously builds a force field using AIMD data. At each time step of the molecular dynamics (MD) simulation, the total energy and forces are predicted based on the MLFF and if the Bayesian error estimate exceeds a threshold, an ab initio calculation is performed, which is used to construct a new force field. Model training of MLFF and evaluation were performed for a range of DJ-LHP models of different thicknesses and halide compositions. The MLFF-MD trajectories were evaluated against pure AIMD trajectories to assess the level of discrepancy and error accumulation. To examine the practical effectiveness of this approach, we have used the MLFF-based MD trajectories to compute NAC and excited-state dynamics. At each stage, results based on machine learning are compared to traditional ab initio based electronic dissipative dynamics. We find that MLFF-MD provides comparable results to AIMDs when MLFF is trained in an NPT ensemble.

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Multiple exciton generation in chiral carbon nanotubes: Density functional theory based computation

Cited by 14 publications

References 63 publications

Biexciton State Energies from Many-Body Perturbation Theory Based on Density Functional Theory Simulation

Biexciton State Energies from Many-Body Perturbation Theory Based on Density Functional Theory Simulation

Dynamics of Excitons in Conjugated Molecules and Organic Semiconductor Systems

Nonadiabatic Dynamics in Two-Dimensional Perovskites Assisted by Machine Learned Force Fields

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