Tunable Out-of-Plane Piezoelectricity in Thin-Layered MoTe<sub>2</sub> by Surface Corrugation-Mediated Flexoelectricity

Kang, Soo‐Jung; Jeon, Sohee; Kim, Sera; Seol, Daehee; Yang, Heejun; Lee, Jaekwang; Kim, Yunseok

doi:10.1021/acsami.8b06325

Cited by 48 publications

(53 citation statements)

References 56 publications

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“…Effective d 33 induced by flexoelectricity on monolayer MoS 2 supported by Al 2 O 3 substrate was 1.35 ± 0.24 pm V −1 reported by Brennan et al . On corrugated thin‐layered MoTe 2 , effective out‐of‐plane piezoelectricity was measured as 3.98 pm V −1 by Kang et al . In our work, the free‐standing structure benefits the observation of the piezoresponse by amplifying the strain gradient as well as avoiding the clamping effect.…”

Section: Resultssupporting

confidence: 65%

“…The effective piezoelectric coefficient obviously dropped off with the number of layers increasing. It could be inferred to the enhancement of flexoelectric effect with the decreasing of flake thickness . The thickness dependence of flexoelectric effect on few‐layer MoS 2 will be disscussed further in the later chapters.…”

Section: Resultsmentioning

confidence: 93%

“…A small force of tip–sample interaction is not enough to change the curvature of naturally suspended membrane, and could avoid the additional mechanical contribution from the tip. The suspended structure could result in a natural curvature in 2D crystal, so that a net dipole moment could be obtained along normal direction of the membrane . In terms of monolayer MoS 2 , polarization in normal direction can be induced at the bent region, as shown in the schematic of Figure b.…”

Section: Resultsmentioning

confidence: 99%

“…The effective out‐of‐plane piezoelectric coefficient (

d_{33}^{eff}

) of monolayer MoS 2 on a flat substrate has been reported as 1.12 pm V −1 . Then, the

d_{33}^{eff}

of thin‐layered corrugation MoTe 2 was obtained as 3.98 pm V −1 . However, strain‐gradient effect induced by substrate for the supported 2D system is technically restricted and ambiguous.…”

Section: Introductionmentioning

confidence: 99%

“…However, strain‐gradient effect induced by substrate for the supported 2D system is technically restricted and ambiguous. And some negative effects, such as clamping effect, parasitic charges, and doping effect, would be inevitably derived from the substrate . The unexpectable experimental error of PFM resulting from the complicated substrate effects should be avoided in 2D piezoelectric systems.…”

Section: Introductionmentioning

confidence: 99%

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Probing Effective Out‐of‐Plane Piezoelectricity in van der Waals Layered Materials Induced by Flexoelectricity

Wang

Cui

Chen

et al. 2019

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Many van der Waals layered 2D materials, such as h‐BN, transition metal dichalcogenides (TMDs), and group‐III monochalcogenides, have been predicted to possess piezoelectric and mechanically flexible natures, which greatly motivates potential applications in piezotronic devices and nanogenerators. However, only intrinsic in‐plane piezoelectricity exists in these 2D materials and the piezoelectric effect is confined in odd‐layers of TMDs. The present work is intent on combining the free‐standing design and piezoresponse force microscopy techniques to obtain and directly quantify the effective out‐of‐plane electromechanical coupling induced by strain gradient on atomically thin MoS2 and InSe flakes. Conspicuous piezoresponse and the measured piezoelectric coefficient with respect to the number of layers or thickness are systematically illustrated for both MoS2 and InSe flakes. Note that the promising effective piezoelectric coefficient (deff33) of about 21.9 pm V−1 is observed on few‐layered InSe. The out‐of‐plane piezoresponse arises from the net dipole moment along the normal direction of the curvature membrane induced by strain gradient. This work not only provides a feasible and flexible method to acquire and quantify the out‐of‐plane electromechanical coupling on van der Waals layered materials, but also paves the way to understand and tune the flexoelectric effect of 2D systems.

show abstract

Section: Resultssupporting

confidence: 65%

Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

“…The effective out‐of‐plane piezoelectric coefficient (

d_{33}^{eff}

) of monolayer MoS 2 on a flat substrate has been reported as 1.12 pm V −1 . Then, the

d_{33}^{eff}

of thin‐layered corrugation MoTe 2 was obtained as 3.98 pm V −1 . However, strain‐gradient effect induced by substrate for the supported 2D system is technically restricted and ambiguous.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Probing Effective Out‐of‐Plane Piezoelectricity in van der Waals Layered Materials Induced by Flexoelectricity

Wang

Cui

Chen

et al. 2019

Small

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Tuning Mixed Electronic/Ionic Conductivity of 2D CdPS₃ Nanosheets as an Anode Material by Synergistic Intercalation and Vacancy Engineering

Yang

Luo

et al. 2022

Adv Funct Materials

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Metal phosphorus trichalcogenides (MPTCs) are structurally adjustable 2D layered materials with unique electronic structures and high chemical diversity, implying the huge potential for energy storage application. In the typical electrochemical reaction process, rapid electron/ion conduction and abundant ion transport channels are the key parameters that influence the overall electrochemical performance of the electrode materials. Herein, 2D Cd 1−x PS 3 Li 2x nanosheets with enhanced mixed electronic/ionic conductivity are synthesized by the intercalation and vacancy strategy. The as-prepared thin-layered Cd 1−x PS 3 Li 2x electrode delivers high capacities of 1056 mAh g −1 at 0.2 A g −1 and 678 mAh g −1 at 8 A g −1 , when used as anode in lithium-ion batteries. The variation of electronic structure and spatial layered structure in Cd 1−x PS 3 Li 2x induced by the synergistic effect of lithium-ion intercalation and Cd vacancies promote the dynamics of mixed electron/ion transport and offer more ion diffusion pathways, resulting in its excellent electrochemical performance. The strategy of mixed electron/ion conduction tuning for Cd 1−x PS 3 Li 2x can be extended to other MPTCs compounds to further develop their potential in the field of energy storage.

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Coupling of Piezo/Flexoelectricity and Its Effect on the Band Structure of Wrinkled ZnO Monolayers

Yin,

Jia,

et al. 2024

Adv Funct Materials

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Wrinkles are used in manufacturing stretchable electronics, soft materials, smart displays, and microstructures. The emerging 2D materials enable the investigation of the intertwined piezoelectric and flexoelectric coupling effect in wrinkled structures and their energy, sensing, and other applications. However, current studies of the electromechanical coupling effect often consider it one effect or even overlook one of the two effects. This oversimplification leads to inaccuracies in the analysis. Here, a theoretical model is proposed to separate the piezoelectric and flexoelectric coefficients by fitting polarization formulas with discrete polarization values calculated using density functional theory. Wrinkled ZnO monolayers are built to mimic the realistic situation, where six nonzero coefficients are successfully isolated, revealing that the coupling of piezo/flexoelectricity and the contribution of piezoelectric and flexoelectric polarizations to the total polarization vary in different directions. Combined with the dipole moment analysis, the relationship between the polarization, piezoelectric coefficient, flexoelectric coefficient, and wrinkle amplitude is established. This study demonstrates that increasing the wrinkle amplitude significantly decreases the energy gap of 560 meV. The separation and quantification of piezoelectric and flexoelectric effects advance the understanding of wrinkles' mechanical and electromechanical properties and lay the foundation for their future applications.

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Tunable Out-of-Plane Piezoelectricity in Thin-Layered MoTe₂ by Surface Corrugation-Mediated Flexoelectricity

Cited by 48 publications

References 56 publications

Probing Effective Out‐of‐Plane Piezoelectricity in van der Waals Layered Materials Induced by Flexoelectricity

Probing Effective Out‐of‐Plane Piezoelectricity in van der Waals Layered Materials Induced by Flexoelectricity

Tuning Mixed Electronic/Ionic Conductivity of 2D CdPS₃ Nanosheets as an Anode Material by Synergistic Intercalation and Vacancy Engineering

Coupling of Piezo/Flexoelectricity and Its Effect on the Band Structure of Wrinkled ZnO Monolayers

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Tunable Out-of-Plane Piezoelectricity in Thin-Layered MoTe2 by Surface Corrugation-Mediated Flexoelectricity

Cited by 48 publications

References 56 publications

Probing Effective Out‐of‐Plane Piezoelectricity in van der Waals Layered Materials Induced by Flexoelectricity

Probing Effective Out‐of‐Plane Piezoelectricity in van der Waals Layered Materials Induced by Flexoelectricity

Tuning Mixed Electronic/Ionic Conductivity of 2D CdPS3 Nanosheets as an Anode Material by Synergistic Intercalation and Vacancy Engineering

Coupling of Piezo/Flexoelectricity and Its Effect on the Band Structure of Wrinkled ZnO Monolayers

Contact Info

Product

Resources

About

Tunable Out-of-Plane Piezoelectricity in Thin-Layered MoTe₂ by Surface Corrugation-Mediated Flexoelectricity

Tuning Mixed Electronic/Ionic Conductivity of 2D CdPS₃ Nanosheets as an Anode Material by Synergistic Intercalation and Vacancy Engineering