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 (C60-L1 and C60-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 C60-L1 and 21,188 for the C60-L2), fast response times (0.99 s for the C60-L1 and 0.97 s for the C60-L2), and low hysteresis effects (6.73% RH for the C60-L1). The inherent hydrophobicity of C60 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 C60 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.