Flexible Inkjet-Printed Heaters Utilizing Graphene-Based Inks.

Area of Science:

• Materials Science
• Nanotechnology
• Electrical Engineering

Background:

• Selective heating is crucial for thermal sensor operation and performance.
• Graphene-based materials offer unique thermoelectrical properties for advanced sensor applications.

Purpose of the Study:

• To evaluate the thermoelectrical response and microheating capabilities of graphene (G) and functionalized reduced graphene oxide (f-rGO) inks.
• To demonstrate the feasibility of inkjet printing for fabricating cost-effective and stable microheaters.

Main Methods:

• Inkjet printing of G and f-rGO inks onto flexible polyimide substrates.
• Characterization of Thermal Coefficients of Resistance (TCR) from -40 to 100 °C.
• Evaluation of microheater performance using infrared thermography and constant current sources.

Main Results:

• Extracted TCR values: TCR_G = -1.05 × 10^-3 °C^-1 and TCR_f-rGO = -3.86 × 10^-3 °C^-1.
• f-rGO and G microheaters reached maximum temperatures of 97.5 °C and 89.9 °C, respectively.
• Demonstrated high repeatability, long-term robustness, and minimal resistance change (<13%) after testing.

Conclusions:

• Inkjet printing enables efficient and stable microheater fabrication using G and f-rGO inks.
• The developed microheaters are suitable for selective heating on non-planar substrates with high endurance.
• This approach offers a cost-effective solution with minimal material waste for thermal sensing and heating applications.