Defects-assisted piezoelectric response in liquid exfoliated MoS₂ nanosheets

Abstract

MoS2 is an intrinsic piezoelectric material which offers applications such as energy harvesting, sensors, actuators, flexible electronics, energy storage and more. Surprisingly, there are not any suitable, yet economical methods that can produce quality nanosheets of MoS2 in large quantities, hence limiting the possibility of commercialisation of its applications. Here, we demonstrate controlled synthesis of highly crystalline MoS2 nanosheets via liquid phase exfoliation of bulk MoS2, following which we report piezoelectric response from the exfoliated nanosheets. The method of piezo force microscopy was employed to explore the piezo response in mono, bi, tri and multilayers of MoS2 nanosheets. The effective piezoelectric coefficient of MoS2 varies from 9.6 to 25.14 pm V−1. We attribute piezoelectric response in MoS2 nanosheets to the defects formed in it during the synthesis procedure. The presence of defects is confirmed by x-ray photoelectron spectroscopy.

Unusual nanoscale piezoelectricity-driven high current generation from a self S-defect-neutralised few-layered MoS2 nanosheet-based flexible nanogenerator

“…It is also worth noting that a decrease in S vacancies (which act as n-type charge carriers) increases the piezoresponse in MoS 2 nanosheets. [44][45][46][47] To further confirm the functional group of the MoS 2 nanosheet-PDMS polymer, Fourier-transform infrared spectroscopy (FTIR) was performed. Fig.…”

“…It is also worth noting that a decrease in S vacancies (which act as n-type charge carriers) increases the piezoresponse in MoS 2 nanosheets. 44–47…”

Improved liquid phase exfoliation technique for the fabrication of MoS2/graphene heterostructure-based photodetector

“…Graphene and MoS 2 dispersion were prepared using the improved LPE method as described in Ref. [ 5 ]. MoS 2 and graphite powders were supplied by Sigma and were of analytical grade (99 %).…”

“…The recent curiosity of researchers in two-dimensional, 2D systems is largely due to their exceptional electrical, optical, and mechanical properties [ [1] , [2] , [3] , [4] ] that depend on the layer thickness and crystalline size [ 5 ]. Examples of this materials include; graphene, silicene [ 6 ], boron nitride (hexagonal) [ 7 ], phosphorene, transition-metal dichalcogenides (TMDs: MoS 2 , MoSe 2 WS 2 , etc.)…”

Superior piezoelectric performance of chemically synthesized transition metal dichalcogenide heterostructures for self-powered flexible piezoelectric nanogenerator

“…Sonochemical assisted hydrothermal technique is a promising way for cost effective scalable production of ultrathin TMDC layers for large area [22] electronic device fabrication. Recent studies have shown that piezoelectricity also exists in few layered two-dimensional materials [26][27][28][29], but with a low piezoelectric response, so improving the piezoelectric performance in TMDC laminates is still a challenge. Engineering van der Waals heterostructure can be used to create novel physical phenomena that provide a fruitful approach to improve the piezoelectric characteristics of two-dimensional layered materials [30].…”