Novel liquid-liquid interface deposition method for thin films of two-dimensional solids

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Two-dimensional (2D) materials and van der Waals heterostructures (vdWHs) are crucial for novel electronic devices.
• Current fabrication methods are slow, costly, and use hazardous chemicals, limiting their application.
• Developing efficient and scalable production techniques is essential for advancing 2D material technology.

Purpose of the Study:

• To introduce a novel, rapid, and environmentally friendly liquid-liquid interface technique for fabricating 2D material films and vdWHs.
• To demonstrate the versatility and scalability of this new method for various 2D materials.
• To overcome the limitations of traditional fabrication processes.

Main Methods:

• Utilizing a liquid-liquid interface approach with aqueous surfactant-stabilized suspensions of 2D materials.
• Transferring the produced ultra-thin films and vdWHs onto arbitrary substrates.
• Characterizing the properties of the fabricated films, including conductivity and transmittance.

Main Results:

• Successful production of ultra-thin films and vdWHs of various 2D materials.
• Demonstrated deposition of transparent, highly conductive few-layer graphene films (conductivity: 7.7 × 10^3–1.26 × 10^5 S m^-1, transmittance: 55–75%).
• Fabricated a vdWH comprising MoS2, WS2, and few-layer graphene.

Conclusions:

• The liquid-liquid interface technique offers a rapid, low-cost, and low-impact alternative for 2D material and vdWH fabrication.
• This generic method is applicable to a wide range of surfactant-stabilizable 2D materials.
• The technique facilitates the development of energy-efficient devices utilizing high-performance 2D materials.