Impact of Transverse Geometry and Substrate Selection on the Sensitivity of Laser-Induced Graphene Temperature Sensors

This study focuses on the influence of transverse dimensions (boundary roughness, line width) and underlayer support on the performance and fabrication of laser-induced graphene (LIG) based temperature sensors. The combined effect of these parameters on the linearity and sensitivity (s) for fabricated temperature sensors are systemically investigated. The results indicate that the fabricated temperature sensor demonstrated negative temperature coefficient (NTC) between 30° C to 100° C temperature range when laser scan speed (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$110-125$</tex>) <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{mm} / \mathrm{s}$</tex> for fixed laser power (20 %) was used for its fabrication. The sensors demonstrate excellent linearity (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R^{2} \approx 0.971-0.998$</tex>) and superior sensitivity (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{S} \sim \mathbf{0. 0 6 9 \%}^{\circ} \mathrm{C}^{-\mathbf{1}}$</tex>). Mechanical stability is validated through 650 bending cycles, demonstrating minimal performance degradation (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$S \sim 0.066^{\circ} \mathrm{C}^{-1}$</tex>). A rapid response time <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\sim 2.1 \mathrm{s})$</tex> confirms its applicability in real-time monitoring. The proposed flexible LIG based temperature sensor offers a scalable, cost-effective alternative to conventional metal-based sensors due one step fabrication process, advancing flexible sensing technologies for healthcare, environmental monitoring, and smart textiles.