Developing a high response and low hysteresis humidity sensor based on C60-Lys

Unique electrical properties and chemical modifiability make fullerenes convenient for the fabrication of various measurement devices. In this paper, the fullerene derivative, C60-Lys, with abundant -OH,-NH2, and -COONa, has been creatively used to obtain a humidity sensor with high response (& UDelta;I/I & AP;2000) and low hysteresis (& UDelta;H & AP;2.9% RH). The response time and recovery time of the C60-Lys sensor reach 24s and 29s respectively in the range of 11-97% relative humidity (RH). Hydrogen bonding and van der Waals forces between fullerene derivatives and water molecules play an important role in the adsorption and desorption of water molecules while the formation of ions causes rapid changes in the impedance of the C60-Lys sensor. It is worth noting that the device has excellent reproducibility and stability. These indicate it is a very good strategy to synthesize new humidity sensing materials by modifying groups on fullerenes to change the hydrophilicity of the surface.

Automated summary

The unique electrical properties and chemical modifiability of fullerenes make them suitable for the fabrication of various measurement devices. In this study, a fullerene derivative called C60-Lys, modified with -OH, -NH2, and -COONa groups, has been creatively used to develop a humidity sensor with high response (>2000) and low hysteresis (<2.9% RH). The sensor shows excellent reproducibility and stability, with a response time of 24s and recovery time of 29s in the range of 11-97% relative humidity (RH). The adsorption and desorption of water molecules on the sensor surface are attributed to hydrogen bonding, van der Waals forces, and ion formation.