Ultra-sensitive low-frequency dual-mode humidity sensor using a methyl red-PVA-graphene oxide composite

Area of Science:

• Materials Science
• Sensor Technology
• Nanotechnology

Background:

• Developing advanced materials for accurate humidity monitoring is crucial for various electronic applications.
• Ternary composites offer unique properties for enhanced sensor performance.

Purpose of the Study:

• To synthesize and characterize a novel ternary composite (MPG) of methyl red (MR), polyvinyl alcohol (PVA), and graphene oxide (GO).
• To fabricate and evaluate the performance of an MPG-based humidity sensor for electronic devices.

Main Methods:

• MPG composite synthesis and characterization using SEM, XRD, FTIR, and UV-visible spectroscopy.
• Fabrication of a humidity sensor via spin coating and thermal annealing.
• Performance testing across a wide humidity range (32-92% RH) and varying temperatures.

Main Results:

• The MPG composite exhibited a crosslinked microstructure conducive to water adsorption.
• The sensor demonstrated high capacitive sensitivity (11 nF/%RH at 100 Hz), rapid response (6s) and recovery (8s) times, and low hysteresis (17.3%).
• Enhanced conductivity was observed with increasing temperature, indicating suitability for diverse thermal conditions.

Conclusions:

• The cost-effective MPG ternary composite shows significant promise for humidity sensing applications.
• The developed sensor is suitable for use in hygrometers and real-time relative humidity monitoring in electronic devices.