Flexible Humidity Sensor Based on a Graphene Oxide-Carbon Nanotube-Modified Co₃O₄ Nanoparticle-Embedded Laser-Induced...

Area of Science:

• Materials Science
• Nanotechnology
• Sensor Technology

Background:

• Flexible electronics require high-performance humidity sensors for evolving monitoring needs.
• Conventional humidity sensors often lack the required sensitivity, response time, or flexibility.
• Developing novel composite materials is key to enhancing sensor performance.

Purpose of the Study:

• To develop an innovative flexible humidity sensor with improved performance.
• To utilize a single-step laser scribing technique for fabricating composite electrodes.
• To optimize the humidity-sensing layer using graphene oxide and multiwalled carbon nanotubes.

Main Methods:

• Fabrication of a flexible in situ cobalt oxide (Co3O4) nanoparticle-embedded laser-induced graphene (Co3O4-LIG) composite electrode via laser scribing.
• Modification of the Co3O4-LIG electrode with a homogenously blended aqueous solution of graphene oxide (GO) and carboxylated multiwalled carbon nanotubes (MWCNTs).
• Characterization of the GO-MWCNTs@Co3O4-LIG sensor's performance, including sensitivity, response/recovery times, and linearity.

Main Results:

• The Co3O4-LIG electrode showed enhanced conductivity and hydrophilicity compared to conventional LIG.
• The GO-MWCNTs@Co3O4-LIG sensor exhibited a high sensitivity of 959.1% (ΔR/R0).
• The sensor achieved rapid response (5 s) and recovery (26 s) times with excellent linearity (R² = 0.994) from 14% to 95% relative humidity.

Conclusions:

• The GO-MWCNTs@Co3O4-LIG composite electrode offers a promising platform for high-performance flexible humidity sensors.
• The synergistic combination of GO, MWCNTs, and Co3O4-LIG significantly enhances sensor characteristics.
• This study provides a practical blueprint for designing and manufacturing advanced flexible humidity sensors.