Point-Defect-Passivated MoS₂ Nanosheet-Based High Performance Piezoelectric Nanogenerator

Area of Science:

• Materials Science
• Nanotechnology
• Energy Harvesting

Background:

• Molybdenum disulfide (MoS2) is a promising material for piezoelectric nanogenerators (PNGs).
• Sulfur vacancies in MoS2 can act as charge traps, hindering device performance.
• Effective passivation strategies are needed to improve MoS2-based PNG efficiency.

Purpose of the Study:

• To investigate the impact of sulfur (S) vacancy passivation on monolayer MoS2 piezoelectric nanogenerators.
• To compare the performance of MoS2 PNGs before and after S treatment.
• To understand how S passivation affects charge carrier density and piezoelectric output.

Main Methods:

• Demonstration of a monolayer MoS2 piezoelectric nanogenerator (PNG).
• Application of a sulfur (S) treatment process to passivate S vacancies on the MoS2 surface.
• Comparative analysis of PNG properties (current, voltage, power) pre- and post-S treatment.

Main Results:

• S treatment effectively passivates sulfur vacancies in monolayer MoS2.
• Passivation reduces charge-carrier density, mitigating the screening effect on piezoelectric polarization.
• Output peak current increased >3x (to 100 pA), voltage increased >2x (to 22 mV).
• Maximum output power increased nearly 10-fold.

Conclusions:

• Sulfur passivation is an effective method to enhance MoS2-based piezoelectric nanogenerator performance.
• Reduced free charge carriers and prevented screening effect lead to significantly improved piezoelectric output.
• This work demonstrates a viable strategy for optimizing MoS2 PNGs for energy harvesting.