Strain-Correlated Piezoelectricity in Quasi-Two-Dimensional Zinc Oxide Nanosheets

Abstract

Two-dimensional (2D) piezoelectric materials have recently drawn intense interest in studying the nanoscale electromechanical coupling phenomenon and device development. A critical knowledge gap exists to correlate the nanoscale piezoelectric property with the static strains often found in 2D materials. Here, we present a study of the out-of-plane piezoelectric property of nanometer-thick 2D ZnO-nanosheets (NS) in correlation to in-plane strains, using in situ via strain-correlated piezoresponse force microscopy (PFM). We show that the strain configuration (either tensile or compressive) can dramatically influence the measured piezoelectric coefficient (d 33 ) of 2D ZnO-NS. A comparison of the out-of-plane piezoresponse is made for in-plane tensile and compressive strains approaching 0.50%, where the measured d 33 varies between 2.1 and 20.3 pm V −1 resulting in an order-of-magnitude change in the piezoelectric property. These results highlight the important role of in-plane strain in the quantification and application of 2D piezoelectric materials.

Giant Electromechanical Effect in Piezoelectric Nanomembranes Based on Hf0.5Zr0.5O2

“…First, it can be an artifact, i.e., it can be caused by the AFM technique itself or by AFM equipment. Second, the piezoelectric coefficient (in the direct, atomistic meaning) can vary due to different mechanical stresses in the HZO on the membrane and on the rigid substrate . Third, the observed effect may be the nanoscopic electromechanical behavior of the predeformed piezoelectric nanomembrane, i.e., we may have observed the operation of a miniature piezo device.…”

“…Second, the piezoelectric coefficient (in the direct, atomistic meaning) can vary due to different mechanical stresses in the HZO on the membrane and on the rigid substrate. 16 Third, the observed effect may be the nanoscopic electromechanical behavior of the predeformed piezoelectric nanomembrane, i.e., we may have observed the operation of a miniature piezo device. Note that all of the above phenomena are related to the flexibility of the piezoelectric bridge membranes.…”

Li Doping‐Mediated Ultrahigh Current Generation from Flexible 2D MoS2 Nanosheets‐Based Nanogenerators

“…[42] Carlos et al measured the d 33 value of quasi-ZnO nanosheets between 2.1 and 20.3 pm V À1 . [43] It has been also reported that even number-layered MoS 2 does not exhibit piezoelectricity due to the centrosymmetrical nature, whereas the odd number layers of the sample exhibited a piezoelectric phenomenon due to noncentrosymmetric nature as the symmetry of MoS 2 layers is broken via applying external mechanical stress. Our present finding also suggests that the as-grown Li-doped MoS 2 nanosheets has an odd number of layers.…”

Energy Harvesting Using ZnO Nanosheet-Decorated 3D-Printed Fabrics

“…Nanoscale electronic device systems and energy harvesting applications are promising for two-dimensional (2D) layered materials. In recent years, interest in 2D materials made of piezoelectric, flexoelectric, triboelectric, and hybrid system has increased. , For emerging wearable electronics technologies, 2D materials are widely used due to their weak interlayer contacts, van der Waals (vdW) interactions, easily connected with the external surface, and high flexibility. − In fact, 2D material/soft matter interfaces have been used in the transfer, printing, and processing of various electronic technologies. These interfaces are crucial for controlling the structural and morphological aspects, adjusting the physical properties, and enhancing the functionality of flexible devices made of soft substrates.…”

“…In recent years, interest in 2D materials made of piezoelectric, flexoelectric, triboelectric, and hybrid system has increased. 12,13 For emerging wearable electronics technologies, 2D materials are widely used due to their weak interlayer contacts, van der Waals (vdW) interactions, easily connected with the external surface, and high flexibility. 14−18 In fact, 2D material/soft matter interfaces have been used in the transfer, printing, and processing of various electronic technologies.…”