High performance humidity sensing based on shear-horizontal plate wave resonator with highly oxidized graphene oxide

Humidity sensors are essential components in environmental monitoring and have widespread applications in healthcare, smart agriculture, and industrial manufacturing. Nevertheless, simultaneously achieving ultrafast response, high sensitivity, and long-term operational stability remains a significant challenge. In this work, we report a high-performance humidity sensor realized by integrating a highly oxidized graphene oxide (HOGO) film as the sensitive layer with a shear-horizontal (SH) plate wave resonator. The HOGO film is synthesized via a modified Hummers method, yielding a high density of oxygen-containing functional groups and structural defects. These features provide abundant water adsorption sites, strong hydrophilicity, and efficient mass transport pathways, which synergistically enhance the humidity-sensing performance. Experimental results demonstrate that the proposed sensor achieves high sensitivities of 14.56 kHz/% RH from 10% to 70% RH and 37.07 kHz/% RH from 70% to 90% RH with a 60 nm-thick HOGO film, along with ultrafast response and recovery times of 60 ms and 0.6 s under open air condition. Using standard evaluation in a closed chamber, the speed of response is 0.4 s and recovery 1.8 s. The sensor also shows good repeatability and long-term stability, characterized by an amplitude variation of only 0.1%. Owing to its outstanding performance, the proposed sensor shows strong potential for applications in health monitoring, non-contact humidity sensing, and human–computer interaction.