Doping Carbon Nanotube Ethylene-Vinyl Acetate Thin Films for Touch-Sensitive Applications

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Transparent conductive films are essential for optoelectronic devices.
• Indium tin oxide (ITO) is brittle and scarce, driving the need for alternatives.
• Carbon nanotube-polymer films present a flexible and abundant option.

Purpose of the Study:

• Investigate the impact of carbon nanotube dimensions on thin film performance.
• Explore chemical doping strategies for enhanced conductivity.
• Develop transparent touch-sensitive devices using optimized films.

Main Methods:

• Processing single-walled carbon nanotubes with ethylene-vinyl acetate polymer.
• Chemical doping using halogenated metals, including CuCl2.
• Percolation analysis to determine film conductivity at low thicknesses.
• Fabrication and testing of transparent touch-sensitive devices.

Main Results:

• Optimized carbon nanotube-polymer films exhibit no percolation effects down to 5 nm thickness.
• CuCl2 identified as an effective and low-cost p-dopant.
• Achieved transparent touch-sensitive devices with an on/off ratio of 10 at 95% optical transmittance.
• Linear relationship found between sheet resistance and touch-sensing on/off ratio.

Conclusions:

• Carbon nanotube-polymer films are viable for transparent touch-sensitive applications.
• Optimized doping and processing enhance film performance and device sensitivity.
• These flexible films offer a promising alternative to traditional transparent conductors.