A High-Performances Flexible Temperature Sensor Composed of Polyethyleneimine/Reduced Graphene Oxide Bilayer for Real-Time Monitoring

The temperature sensors are urgently required for real-time temperature monitoring in healthcare, disease diagnosis, and other areas. In this work, a skin-attachable flexible temperature sensor composed of polyethyleneimine/reduced graphene oxide bilayer is developed on polyimide substrate by a facile spray-dipping process. The spectroscopy properties of sensing films are examined and analyzed in details and demonstrated the partial reduction of graphene oxide film. The prepared sensor exhibits high sensitivity (1.30% degrees C-1), linearity (R-2 = 0.999), accuracy (0.1 degrees C), and durability (60 d) for temperature sensing between 25 and 45 degrees C, which can fully satisfy the requirements of real-time and long-term skin temperature monitoring. Additionally, the practical applications in monitoring human skin temperature, breathing rate, finer touch, blow, and water droplet are performed, revealing its great potential in e-skin, disease diagnosis, healthcare, and other fields.