Humidity Sensor Based on ZnO MS/GR Composite Material

Humidity sensors are commonly utilized in a variety of fields. However, present humidity detection devices have many liabilities, such as narrow ranges, poor repeatability, and short lifespans. Therefore, it is essential to explore new humidity sensors with high sensitivity. Here, a new humidity sensor based on ZnO microspheres (MS) decorated with graphene (GR) is introduced. The sensing range of the ZnO MS/GR sensor has been measured to be 20–95% relative humidity (RH). The ZnO MS/GR sensor achieves a large change in resistance of over 4 orders of magnitude, which is 1–2 orders larger than ZnO or GR humidity sensors. The enhanced humidity-sensing performance of the ZnO MS/GR nanocomposite is attributed to the Grotthuss mechanism and the combined effect of the heterojunction at the ZnO/GR interface. This work demonstrates a new humidity sensor with high performance based on a ZnO MS/GR nanocomposite, which may impact future humidity-sensing fields.