Liquid Phase Isolation of SnS Monolayers with Enhanced Optoelectronic Properties.

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Atomically thin two-dimensional (2D) anisotropic materials, like metal monochalcogenides (MMCs), offer unique properties but face challenges in monolayer isolation.
• Tin (II) sulfide (SnS) is a promising earth-abundant MMC with tunable bandgap and anisotropic properties for electronics and optoelectronics.
• Strong interlayer interactions in SnS, due to sulfur lone-pair electrons, hinder the isolation of large-quantity single layers.

Purpose of the Study:

• To develop a novel method for overcoming strong interlayer binding energy in SnS.
• To enable the systematic isolation of highly crystalline SnS monolayers (1L-SnS) in large quantities.
• To explore the electronic and optoelectronic properties of exfoliated 1L-SnS for device applications.

Main Methods:

• A novel liquid phase exfoliation approach combining thermal energy and ultrasound-induced hydrodynamic force.
• Synergistic application of external thermal energy and hydrodynamic force in solution to overcome interlayer binding energy.
• Fabrication and characterization of monolayer SnS transistor devices from solution.

Main Results:

• Successful isolation of highly crystalline SnS monolayers (1L-SnS) using the novel liquid exfoliation method.
• Exfoliated 1L-SnS crystals exhibit high carrier mobility and deep-UV spectral photodetection with a 400 ms response time.
• Solution-processed SnS transistor devices show a high on/off ratio, responsivity of 6.7 × 10^-3 A W^-1, and remarkable ambient stability.

Conclusions:

• The developed liquid phase exfoliation method effectively enables large-scale isolation of highly crystalline SnS monolayers.
• This advancement opens new possibilities for fabricating nanoelectronic devices and printed electronics using SnS.
• The findings pave the way for utilizing SnS and other MMCs in advanced electronic and optoelectronic applications.