Highly Robust Neutral Plane Oxide TFTs Withstanding 0.25 mm Bending Radius for Stretchable Electronics

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Flexible electronics require mechanically stable thin-film transistors (TFTs).
• Ultrathin plastic substrates offer flexibility but lack mechanical stability during fabrication.
• Handling free-standing ultrathin films is challenging for device manufacturing.

Purpose of the Study:

• To develop a fabrication method for mechanically stable TFTs on ultrathin substrates.
• To ensure TFT performance is maintained under mechanical stress like folding and stretching.
• To enable the creation of highly flexible and durable electronic devices.

Main Methods:

• Utilized a 1.5 μm polyimide (PI) substrate and a top PI film to position TFTs at the neutral plane (NP).
• Employed a carrier glass coated with carbon nanotubes (CNTs) and graphene oxide (GO) for mechanical support during fabrication.
• Developed a detachment method using the CNT/GO mixture for transferring NP TFTs to a polydimethylsiloxane (PDMS) substrate.

Main Results:

• Achieved high folding stability by locating TFTs at the neutral bending plane between two PI films.
• Successfully transferred NP TFTs to PDMS substrates without performance degradation.
• Demonstrated excellent mechanical stability of NP TFTs after stretching the PDMS substrate up to 25% elongation.

Conclusions:

• The neutral plane TFT fabrication method enhances mechanical stability for flexible electronics.
• This technique overcomes handling difficulties associated with ultrathin substrates.
• The developed NP TFTs are suitable for applications requiring high stretchability and durability.