Study of Energetics of Polaron Dynamics in Monolayer and Bulk MoS<sub>2</sub> Using Oxidation-State Constrained Density Functional Theory

Ku, Calvin; Sit, Patrick H.‐L.

doi:10.1021/acs.jpcc.2c03201

Cited by 4 publications

(9 citation statements)

References 37 publications

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“…130 meV) and MoS 2 (ca. 170 meV), which yields λ ≅ 150 meV, similar to the value of Δ G 0 . Apparently, this system provides optimum conditions for the efficient charge transfer.…”

Section: Discussionsupporting

confidence: 59%

Influence of the Energy Level Alignment on Charge Transfer and Recombination at the Monolayer-MoS₂/Organic Hybrid Interface

et al. 2023

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Monolayer (ML) transition-metal dichalcogenides (TMDCs) exhibit numerous unique optoelectronic features. This motivates recent efforts to combine TMDCs with organic semiconductors to form heterostructures with tailorable properties that feature the advantages of both materials. Here, we study the photoinduced charge transfer across hybrid interfaces of ML-MoS 2 and a series of organic semiconductors�often used as hole transport materials�where we systematically tune the offsets of the frontier energy levels. Steady-state photoluminescence and ultrafast transient absorption spectroscopy reveal that a larger energy level offset causes a lower efficiency of photoinduced charge transfer but also a longer lifetime of the charge separated state. Both observations are explained in the framework of Marcus' theory of electron transfer. In fact, our observations question direct electron−hole recombination across the hybrid interface as the main decay pathway for photogenerated carriers in the considered systems. Instead, back transfer of holes to ML-MoS 2 is suggested as the key decay channel. Adding a 1 nm LiF interlayer causes a significant slowdown of interfacial carrier recombination while not suppressing free carrier formation. This strategy serves as a guideline for optimizing further hybrid systems toward high-performance ML-TMDC/organic-based optoelectronic devices.

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“…130 meV) and MoS 2 (ca. 170 meV), which yields λ ≅ 150 meV, similar to the value of Δ G 0 . Apparently, this system provides optimum conditions for the efficient charge transfer.…”

Section: Discussionsupporting

confidence: 59%

Influence of the Energy Level Alignment on Charge Transfer and Recombination at the Monolayer-MoS₂/Organic Hybrid Interface

et al. 2023

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“…The one exception is for the electron polaron hopping between two neighboring octahedral sites for the system with an oxygen vacancy, found in cases 4 and 5 of Table . In these cases, the procedure used to calculate the activation energies and electron transfer rates is discussed in section S3 of the Supporting Information of our previous work . We first discuss the results for the pristine system.…”

Section: Resultsmentioning

confidence: 99%

“…This allows direct control of the oxidation state of a target transition metal ion. , Details on OS-CDFT can be found in our previous work, where we demonstrated the capability of OS-CDFT to study electron transfer processes such as the aqueous ferrous-ferric self-redox reaction, polaron transfer in anatase and BiVO 4 , and the origins of corundum sapphire’s blue color. We also studied the effect of S and Mo vacancies on the electron transfer in bulk and monolayer MoS 2 . Aside from electron transfer calculations, we also explored the application of the OS-CDFT method to calculate optical band gaps and dopant state energies in transition metal oxides .…”

Section: Methodsmentioning

confidence: 99%

“…We also studied the effect of S and Mo vacancies on the electron transfer in bulk and monolayer MoS 2 . 20 Aside from electron transfer calculations, we also explored the application of the OS-CDFT method to calculate optical band gaps and dopant state energies in transition metal oxides. 21 The OS-CDFT code has been implemented in the quantum ESPRESSO package.…”

Section: Oxidation State Constrained Density Functionalmentioning

confidence: 99%

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Ab Initio Study of Electron and Hole Polaron Transport in Cobalt(II,III) Oxide Using Oxidation-State Constrained Density Functional Theory

Sit

2023

J. Phys. Chem. C

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The nature of electron and hole polaron transport in the mixed valence cobalt(II,III) oxide Co 3 O 4 in pristine conditions and with an oxygen vacancy are studied using Oxidation-State Constrained DFT (OS-CDFT). We find that the tetrahedral site repels electron polarons as hopping from a neighboring octahedral site toward the tetrahedral site is highly endothermic while hopping away toward a neighboring octahedral site is nearly instantaneous. Hence, electron polarons travel through bulk Co 3 O 4 using pathways through only octahedral Co ions. In contrast, while the purely octahedral pathways remain the dominant pathway for hole polaron transport, the pathways involving both the octahedral and tetrahedral sites are still viable with about two thirds the rate of the octahedral pathways. Moreover, the purely octahedral pathway is enhanced with an oxygen vacancy for both the electron and hole polarons. On the other hand, pathways involving both the octahedral and tetrahedral sites are impeded in the presence of an oxygen vacancy for both the electron and hole polarons due to increased magnitude of driving forces.

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“…In detail, when an excess electron passes through the semiconductor, the self-trapping phenomenon will happen (i.e., the formation of a small polaron, see Supplementary Note in Supplementary Information) and cause sluggish charge transportation, 39,40 which accounts for the poor electrical conductivity in 2H-MoS 2 . 41 Meanwhile, Goodenough and other researchers also suggested that symmetry-breaking states introduced by defects or insertions will induce polaron preemption (or polaron collapse), thus electron transportation can be accelerated. 42,43 For instance, spin-polarized electrons (i.e., typical symmetry-breaking states) are recently observed in monolayer MoS 2 , which owns a better electrical conductivity than the bulk phase.…”

Section: Introductionmentioning

confidence: 99%

[MoS] Insertion Chains Induced Small-Polaron Collapse in MoS2 2D Layers: A Novel Mo2S3 Anode for Ultrafast Sodium Storage

Zhao

Xie

et al. 2023

Preprint

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Molybdenum disulfide (MoS2) with high theoretical capacity has been viewed as a promising anode for sodium-ion batteries, but suffers from inferior rate capability owing to the polaron-induced slow charge transfer. Herein, we proposed a polaron collapse strategy induced by electron-rich insertions to effectively solve the above issue. Specifically, 1D [MoS] chains are inserted into MoS2 to break the symmetry states of 2D layers and induce small-polaron collapse to gain fast charge transfer, so that the as-obtained thermodynamically stable Mo2S3 shows metallic behavior with 107 times larger electrical conductivity than that of MoS2. Theoretical calculations demonstrate that Mo2S3 owns highly delocalized anions, which substantially reduces the interactions of Na − S to efficiently accelerate Na+ diffusion, endowing Mo2S3 lower energy barrier (0.38 vs 0.65 eV of MoS2). The novel Mo2S3 anode exhibits a high capacity of 510 mAh g− 1 at 0.5 C and a superior high-rate stability of 217 mAh g− 1 at 40 C over 15000 cycles. Further in situ and ex situ characterizations reveal the in-depth reversible redox chemistry in Mo2S3. The proposed polaron collapse strategy for intrinsically facilitating charge transfer could be conducive to electrode design for fast-charging batteries.

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Study of Energetics of Polaron Dynamics in Monolayer and Bulk MoS₂ Using Oxidation-State Constrained Density Functional Theory

Cited by 4 publications

References 37 publications

Influence of the Energy Level Alignment on Charge Transfer and Recombination at the Monolayer-MoS₂/Organic Hybrid Interface

Influence of the Energy Level Alignment on Charge Transfer and Recombination at the Monolayer-MoS₂/Organic Hybrid Interface

Ab Initio Study of Electron and Hole Polaron Transport in Cobalt(II,III) Oxide Using Oxidation-State Constrained Density Functional Theory

[MoS] Insertion Chains Induced Small-Polaron Collapse in MoS2 2D Layers: A Novel Mo2S3 Anode for Ultrafast Sodium Storage

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Study of Energetics of Polaron Dynamics in Monolayer and Bulk MoS2 Using Oxidation-State Constrained Density Functional Theory

Cited by 4 publications

References 37 publications

Influence of the Energy Level Alignment on Charge Transfer and Recombination at the Monolayer-MoS2/Organic Hybrid Interface

Influence of the Energy Level Alignment on Charge Transfer and Recombination at the Monolayer-MoS2/Organic Hybrid Interface

Ab Initio Study of Electron and Hole Polaron Transport in Cobalt(II,III) Oxide Using Oxidation-State Constrained Density Functional Theory

[MoS] Insertion Chains Induced Small-Polaron Collapse in MoS2 2D Layers: A Novel Mo2S3 Anode for Ultrafast Sodium Storage

Contact Info

Product

Resources

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Study of Energetics of Polaron Dynamics in Monolayer and Bulk MoS₂ Using Oxidation-State Constrained Density Functional Theory

Influence of the Energy Level Alignment on Charge Transfer and Recombination at the Monolayer-MoS₂/Organic Hybrid Interface

Influence of the Energy Level Alignment on Charge Transfer and Recombination at the Monolayer-MoS₂/Organic Hybrid Interface