Achieving Predictive Description of Negative Differential Resistance in Molecular Junctions Using a Range‐Separated Hybrid Functional

Bhandari, Srijana; Yamada, Atsushi; Hoskins, Austin; Payne, Jameson; Aksu, Hüseyin; Dunietz, Barry D.

doi:10.1002/adts.202000016

“…A computational investigation is well-positioned to address this question, where the orbital energies are found by considering the complex many-body interactions between the subsystems. Density functional theory (DFT) is used most frequently, analyzing the charge density distribution and energetics − in interfacial systems. These calculations are affordable for systems of thousands of electrons .…”

mentioning

confidence: 99%

Exceptional Spatial Variation of Charge Injection Energies on Plasmonic Surfaces

Lei,

Canestraight,

Vlcek

2023

J. Phys. Chem. Lett.

1

0

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Charge injection into a molecule on a metallic interface is a key step in many photoactivated reactions. We employ the many-body perturbation theory and compute the hole and electron injection energies for CO 2 molecule on an Au nanoparticle with ∼3,000 electrons and compare it to results for idealized infinite surfaces. We demonstrate a surprisingly large variation of the injection energy barrier depending on the precise molecular position on the surface. Multiple "hot spots," characterized by low energy barriers, arise due to the competition between the plasmonic coupling and the degree of hybridization between the molecule and the substrate. The charge injection barrier to the adsorbate on the nanoparticle surface decreases from the facet edge to the facet center. This finding contrasts with the typical picture in which the electric field enhancement on the nanoparticle edges is considered the most critical factor.

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“…This limitation can be addressed by using a range-separated hybrid (RSH) functionals, which have been demonstrated to predict better HOMO-LUMO gaps 58 and provide realistic conductance estimates. 59,60 Interestingly, the calculated conductance using CAM-B3LYP, an RSH functional (SI, Section 7) yields similar qualitative trends as of B3LYP with improved conductance values, but at the cost of severe spin contamination in OSS state.…”

Section: Computational Methodologymentioning

confidence: 76%

Anti-ohmic Nanoconductors: Myth, Reality and Promise

Bajaj

¹

,

Ali

²

2023

Preprint

0

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The recent accomplishments in the design of molecular nanowires characterised by an increasing conductance with length has embarked the origin of extraordinary new family of molecular junctions referred to as "anti-ohmic" wires. Herein, this highly desirable, non-classical behavior, has been examined for the longer enough molecules exhibiting pronounced diradical character in their ground state within the unrestricted DFT formalism with spin and spatial symmetry breaking. We demonstrate that highly conjugated acenes signals higher resistance in open-shell singlet (OSS) configuration as compared to their closed-shell counterparts. This anomaly has been further put to proof for experimentally certified cumulene wires, which reveals phenomenal modulation in the transport characteristics such that an increasing conductance is observed in closed-shell limit, while higher cumulenes in OSS ground state yields a regular decay of conductance.

show abstract

“…This limitation can be addressed by using a range-separated hybrid (RSH) functionals, which have been demonstrated to predict better HOMO-LUMO gaps 59 and provide realistic conductance estimates. 60,61 Interestingly, the calculated conductance using CAM-B3LYP, an RSH functional (SI, Section 7) yields similar qualitative trends as of B3LYP with improved conductance values, but at the cost of severe spin contamination in OSS state.…”

Section: Methodsmentioning

confidence: 76%

Anti-ohmic Nanoconductors: Myth, Reality and Promise

Bajaj

¹

,

Ali

²

2022

Preprint

0

View full text Add to dashboard Cite

The recent accomplishments in the design of molecular nanowires characterised by an increasing conductance with length has embarked the origin of extraordinary new family of molecular junctions referred to as "anti-ohmic" wires. Herein, this highly desirable, non-classical behavior, has been examined for the longer enough molecules exhibiting pronounced diradical character in their ground state within the unrestricted DFT formalism with spin and spatial symmetry breaking. We demonstrate that highly conjugated acenes signals higher resistance in open-shell singlet (OSS) configuration as compared to their closed-shell counterparts. This anomaly has been further put to proof for experimentally certified cumulene wires, which reveals phenomenal modulation in the transport characteristics such that an increasing conductance is observed in closed-shell limit, while higher cumulenes in OSS ground state yields a regular decay of conductance.

show abstract

Achieving Predictive Description of Negative Differential Resistance in Molecular Junctions Using a Range‐Separated Hybrid Functional

Cited by 6 publications

References 102 publications

Exceptional Spatial Variation of Charge Injection Energies on Plasmonic Surfaces

Exceptional Spatial Variation of Charge Injection Energies on Plasmonic Surfaces

Anti-ohmic Nanoconductors: Myth, Reality and Promise

Anti-ohmic Nanoconductors: Myth, Reality and Promise

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