Defects-assisted piezoelectric response in liquid exfoliated MoS₂nanosheets

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Molybdenum disulfide (MoS2) is a promising intrinsic piezoelectric material.
• Current production methods for MoS2 nanosheets are not economical or scalable.
• This limits the commercialization of MoS2-based applications like energy harvesting and sensors.

Purpose of the Study:

• To develop a scalable and economical method for synthesizing high-quality MoS2 nanosheets.
• To investigate and quantify the piezoelectric response of these synthesized MoS2 nanosheets.
• To understand the relationship between synthesis-induced defects and piezoelectricity in MoS2.

Main Methods:

• Controlled synthesis of MoS2 nanosheets via liquid phase exfoliation of bulk MoS2.
• Piezo force microscopy (PFM) to characterize piezoelectric response in various MoS2 nanosheet layers (mono, bi, tri, and multilayers).
• X-ray photoelectron spectroscopy (XPS) to confirm the presence of defects.

Main Results:

• Successfully synthesized highly crystalline MoS2 nanosheets using liquid phase exfoliation.
• Demonstrated and quantified piezoelectric response in MoS2 nanosheets, with coefficients ranging from 9.6 to 25.14 pm/V.
• Identified synthesis-induced defects as the source of piezoelectricity, confirmed by XPS.

Conclusions:

• Liquid phase exfoliation offers a viable route for large-scale MoS2 nanosheet production.
• MoS2 nanosheets exhibit significant piezoelectric properties, tunable by defect concentration.
• This work paves the way for commercial applications of MoS2 in flexible electronics and energy harvesting devices.