Multifunctional Transparent Conductive Flexible Sensor Based on Graphene/Polyaniline/ Graphene Sandwich Composite on PDMS Substrate

A novel and simplified method is introduced for synthesizing a transparent sensor based on graphene-polydimethylsiloxane (PDMS). The chemical vapor deposition (CVD)-grown single-layer graphene on the PDMS substrate suffers from low conductivity due to defects at grain boundaries. The fabricated sensor incorporates a polyaniline (PANI) layer between two graphene layers to maintain enhanced conductivity even when subjected to strain, due to its flexibility. The tri-layer structure of graphene-PANI–graphene (G-P–G) achieves approximately 90% transmittance and a lower sheet resistance (≈ 84~Ω/Sq) on a flexible substrate that surpasses those achieved with a single-layer graphene on PDMS and other sandwich structures on a PDMS substrate. The developed transparent and highly conductive G-P–G sensor exhibits effective sensing for finger tapping/touch, strain detection, human motion detection, wrist pulse detection, breathing detection, and traditional NADI detection. This underscores its versatility for various sensing applications. In summary, the demonstrated results indicate the potential of this single transparent conductive sensor structure for deployment in diverse and multifunctional sensing applications.