Energy-efficient Flexible Ammonia Sensors Enabled by Polypyrrole-Graphene

Two Dimensional (2D) materials and their combination with conductive polymers are emerging candidates for high-performance gas sensing with desirable mechanical flexibility. It is of great importance to understand the influence of applied strain to the sensing performance of such flexible sensors. In this work, we investigated the combination of graphene and polypyrrole (PPy) as flexible sensor devices and explored their ammonia sensing performance in-situ at bending. While having 1–5% responsivity when exposed to 5–35 ppm ammonia in flat condition, the response is raised generally under increasing strain denoted as the radius of curvature from 10 mm to 4 mm, with a peak value of 2.3% in 5 ppm NH3. Notably, the power consumption of our PPy-graphene sensor could be as low as $17 \mu\mathrm{W}$. This work suggests PPy-graphene hybrid as energy-efficient and high-performance flexible sensor towards electronic skin for environmental monitoring.