Charge Transport and Separation Dynamics at the C<sub>60</sub>/GaAs(001) Interface

Kim, Jeong Won; Park, Heungman; Zhu, Xiaoyang

doi:10.1021/jp412180t

Cited by 6 publications

(10 citation statements)

References 31 publications

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“…Previous ultrafast surface science investigations have shown that the dynamics of an electronic state in a molecular film can differ based on the molecular properties of the film, the electronic state localization, influence of the metal substrate, and molecular film thickness. 8,10,[27][28][29][30][31][32][33][34][35] The contrasting dynamics of electron localization in nonpolar n-heptane versus polar water and ammonia highlight the influence of the molecular properties of the film. In ultra-thin non-polar n-heptane layers on a Ag(111) surface, electron injection leads to the formation of small polarons that are self-trapped via the in-phase methylene rocking of n-heptane on an approximately 360 fs timescale.…”

Section: Introductionmentioning

confidence: 99%

Multistep and multiscale electron transfer and localization dynamics at a model electrolyte/metal interface

King

Broch

Demling

et al. 2018

The Journal of Chemical Physics

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The lifetime, coupling, and localization dynamics of electronic states in molecular films near metal electrodes fundamentally determine their propensity to act as precursors or reactants in chemical reactions, crucial for a detailed understanding of charge transport and degradation mechanisms in batteries. In the current study, we investigate the formation dynamics of small polarons and their role as intermediate electronic states in thin films of dimethyl sulfoxide (DMSO) on Cu(111) using time-and angle-resolved two-photon photoemission spectroscopy. Upon photoexcitation, a delocalized DMSO electronic state two monolayers from the Cu surface is initially populated, becoming a small polaron on a 200 fs timescale, consistent with localization due to vibrational dynamics of the DMSO film. The small polaron is a precursor state for an extremely long-lived and weakly-coupled multilayer electronic state, with a lifetime of several seconds, thirteen orders of magnitude longer than the small polaron. Although the small polaron in DMSO has a lifetime of 140 fs, its role as a precursor state for long-lived electronic states could make it an important intermediate in multistep battery reactivity.

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Section: Introductionmentioning

confidence: 99%

Multistep and multiscale electron transfer and localization dynamics at a model electrolyte/metal interface

King

Broch

Demling

et al. 2018

The Journal of Chemical Physics

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“…One way to utilize the hot carriers for enhancing the efficiency of photo energy conversion is to realize a charge separation at the interfaces by extracting the hot carriers from the photoconverter before they cool, which can also produce an enhanced photovoltage and suppress the electron–hole recombination. , In order to realize this, the interfacial charge transfer across the contacts must be faster than the rate of carrier cooling . Although numerous experimental and theoretical studies have been carried out to investigate the charge separation mechanism at the interface of hybrid solar cells in order to develop high-efficiency photovoltaic or photocatalysis materials, − it is still one of the most important and challenging problems in this field.…”

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confidence: 99%

Superatom Molecular Orbital as an Interfacial Charge Separation State

Guo

Zhao

Zheng

et al. 2018

J. Phys. Chem. Lett.

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Hot electron cooling by energy loss to heat through electron-phonon (e-ph) interaction is an important mechanism that can limit the efficiency of solar energy conversion. To avoid such energy loss, sufficient charge separation needs to be realized by extracting hot carriers from the photoconverter before they cool, which requires fast interfacial charge transfer and slow internal hot carrier relaxation. Using ab initio time-dependent nonadiabatic molecular dynamics and taking C/MoS as a prototype system, we show that the superatom molecular orbitals (SAMOs) of fullerenes, which are bound by the central potential of the whole molecule induced by the charge screening, are ideal media for charge separation. The diffuse character of SAMOs results in extremely weak e-ph interaction and therefore acts as a "phonon bottleneck" for hot electron cooling. Furthermore, it also leads to significant hybridization with other atoms at the interface that induces fast charge transfer. The interfacial charge-transfer rate at the C/MoS interface is found to be 2 orders of magnitude faster than the hot electron cooling from s-SAMO in C. This conclusion is generally applicable for different carbon nanostructures that have SAMOs. The proposed SAMO-induced charge separation provides unique and essential insights into the material design and function for solar energy conversion.

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“…97,98 In such a charge separation process, it is required that the interfacial charge transfer across the contacts must be faster than the rate of carriers cooling. 99 In spite of numerous investigations on the charge separation mechanism at the hybrid solar cell interfaces, 98,[100][101][102][103][104][105][106][107][108][109][110] this is still one of the most important and challenging problems in this field. Using NAMD simulations, Guo et al 111 proposed that the superatom molecular orbitals (SAMOs) and the nearly free electron (NFE) states of carbon nanostructures which were initially discovered by Feng et al, 112 is an ideal media for interfacial charge separation.…”

Section: Superatom Molecular Orbital As An Interfacial Charge Separmentioning

confidence: 99%

Ab initio nonadiabatic molecular dynamics investigations on the excited carriers in condensed matter systems

Zheng

Chu

Zhao

et al. 2019

WIREs Comput Mol Sci

272

258

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The ultrafast dynamics of photoexcited charge carriers in condensed matter systems play an important role in optoelectronics and solar energy conversion. Yet it is challenging to understand such multidimensional dynamics at the atomic scale. Combining the real‐time time‐dependent density functional theory with fewest‐switches surface hopping scheme, we develop time‐dependent ab initio nonadiabatic molecular dynamics (NAMD) code Hefei‐NAMD to simulate the excited carrier dynamics in condensed matter systems. Using this method, we have investigated the interfacial charge transfer dynamics, the electron–hole recombination dynamics, and the excited spin‐polarized hole dynamics in different condensed matter systems. The time‐dependent dynamics of excited carriers are studied in energy, real and momentum spaces. In addition, the coupling of the excited carriers with phonons, defects and molecular adsorptions are investigated. The state‐of‐art NAMD studies provide unique insights to understand the ultrafast dynamics of the excited carriers in different condensed matter systems at the atomic scale. This article is categorized under: Structure and Mechanism > Computational Materials Science Molecular and Statistical Mechanics > Molecular Dynamics and Monte‐Carlo Methods Electronic Structure Theory > Ab Initio Electronic Structure Methods Software > Simulation Methods

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Charge Transport and Separation Dynamics at the C₆₀/GaAs(001) Interface

Cited by 6 publications

References 31 publications

Multistep and multiscale electron transfer and localization dynamics at a model electrolyte/metal interface

Multistep and multiscale electron transfer and localization dynamics at a model electrolyte/metal interface

Superatom Molecular Orbital as an Interfacial Charge Separation State

Ab initio nonadiabatic molecular dynamics investigations on the excited carriers in condensed matter systems

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Charge Transport and Separation Dynamics at the C60/GaAs(001) Interface

Cited by 6 publications

References 31 publications

Multistep and multiscale electron transfer and localization dynamics at a model electrolyte/metal interface

Multistep and multiscale electron transfer and localization dynamics at a model electrolyte/metal interface

Superatom Molecular Orbital as an Interfacial Charge Separation State

Ab initio nonadiabatic molecular dynamics investigations on the excited carriers in condensed matter systems

Contact Info

Product

Resources

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Charge Transport and Separation Dynamics at the C₆₀/GaAs(001) Interface