Graphene-Based Temperature Sensors-Comparison of the Temperature and Humidity Dependences

Area of Science:

• Materials Science
• Nanotechnology
• Sensor Technology

Background:

• Graphene's unique properties make it suitable for advanced sensor applications.
• Developing high-performance temperature and humidity sensors is crucial for various industries.

Purpose of the Study:

• To prepare and characterize four types of graphene-based temperature sensors.
• To evaluate the temperature and humidity dependence of these sensors.
• To compare their performance against standard sensors.

Main Methods:

• Graphene sensors were fabricated using reduced graphene oxide (rGO), graphene nanoplatelets (Gnp), plasma-grown graphene (Gpl), and chemical vapor deposition graphene (Gcvd).
• Materials characterization included scanning electron microscopy (SEM), energy-dispersive X-ray diffraction (EDX), and X-ray photoelectron spectroscopy (XPS).
• Temperature and humidity sensing properties were systematically tested.

Main Results:

• rGO and Gnp sensors exhibited the highest change in resistance with temperature, with temperature coefficients of resistance (TCR) of 5.16×10⁻³ K⁻¹ (Gnp) and 4.86×10⁻³ K⁻¹ (rGO).
• These TCR values surpass that of conventional platinum thermistors.
• Gpl and Gcvd sensors demonstrated minimal dependence on relative humidity due to lower oxygen group content.

Conclusions:

• Graphene sensors based on small flake structures (rGO, Gnp) offer enhanced temperature sensing capabilities.
• Graphene sensors with reduced oxygen functional groups (Gpl, Gcvd) provide improved humidity resistance.
• The choice of graphene preparation method significantly impacts sensor performance characteristics.