Highly Sensitive Fullerene-Loaded Ionic Liquid Humidity Sensor for Respiratory Monitoring and Non-Contact Switching

In this work, the superhydrophilic ionic liquid (IL) was loaded on a hydrophobic fullerene surface, and two humidity-sensitive materials (C 60 -L1 and C 60 -L2) were synthesized to prepare fast-response humidity sensors. The sensors exhibit excellent sensitivity with response values spanning 5 orders of magnitude (16,629 for the C 60 -L1 and 21,188 for the C 60 -L2), fast response times (0.99 s for the C 60 -L1 and 0.97 s for the C 60 -L2), and low hysteresis effects (6.73% RH for the C 60 -L1). The inherent hydrophobicity of C 60 regulates the strong hydrophilicity of the ionic liquid, allowing it to respond normally even at high humidity, and the large specific surface area and excellent electrical properties of C 60 are favorable for proton conduction. In addition, the sensor demonstrates utility in respiratory monitoring and noncontact switching, highlighting its potential for healthcare and environmental applications.