A high-sensitivity MoS₂/graphene oxide nanocomposite humidity sensor based on surface acoustic wave

We herein propose a surface acoustic wave (SAW) sensor coating with a MoS2/graphene oxide (GO) nano composite. MoS2 nanosheets were prepared using the liquid stripping method, and the MoS2/GO nanoflakes were characterized by scanning electron microscopy. Subsequently, the surface acoustic sensor was prepared using a standard photolithographic technique and the MoS2/GO layers were deposited via drop-casting on the sensor surfaces. The performance of the sensor was then tested from 20% relative humidity (RH) to 95% RH. The sensor exhibits good performance with a sensitivity of 114 ppm/%RH at low humidity (at 20-70% RH) and a sensitivity of 766.8 ppm/%RH at high humidity (at 70-95% RH). The recovery and response time of the sensor were 6.6 s and 3.5 s. Moreover, the sensor exhibited good repeatability and long-term stability. The influence of temperature on sensor response at different values of humidity was also tested, and the relationship between temperature and frequency was almost linear from 25 to 70 degrees C at different humidity levels. Finally, the humidity sensitive mechanism was analyzed at different humidity values. The humidity sensor has great application potential in medical care, environmental monitoring, and cultural relic preservation.