Sustainable sensor technology: Laser-induced graphene based capacitive sensors on wooden substrates for touch and liquid level detection

Abstract

Sustainable graphene based interdigitated capacitive sensors are gaining popularity as an alternative to sophisticated existing sensors, which often feature complex mechanical designs tailored for specific applications like touch detection, light touch detection, and liquid level sensing. This research introduces laser-induced graphene(LIG) based capacitive sensors fabricated on wooden substrates, offering an energy-efficient, cost-effective, and environmentally friendly solution. Utilizing the unique properties of wood and the precision of laser technology, we fabricated graphene layer on wood and optimized the fabrication parameters to achieve maximum capacitance and sensitivity. The graphene sensors demonstrated average touch sensitivity of response Δ C/C₀ of 31 % in capacitive touch sensing, showcasing their practical utility in diverse applications. These sensors serve as a proof-of-concept for sensor fabrication and operational mechanisms, intended for educational purposes due to their simple fabrication process and straightforward working principle. In the context of water level sensing, its sensitivity has been measured to be 1.8 pF per cm. These sustainable sensors not only meet the performance demands of modern applications but also contribute to reducing electronic waste and promoting biodegradable materials. This study paves the way for the development of eco-friendly and economical sensors that align with global sustainability goals. Due to its ability to detect dielectric materials, the LIG electrode graphene based IDC sensor can be integrated into various modern technologies and devices, it provides long-range sensing, be cost-effective, consume low power, and be environmentally friendly.