Highly sensitive and fast response Love wave mode humidity sensor based on MoS2@Ti3C2Tx hierarchical structure

Abstract

Humidity sensing is crucial for food production, environmental monitoring, microelectronic manufacture, and common living conditions. Thus, there is a high demand for development of high-performance humidity sensors with good stability, high precision and fast responses. In this study, Love wave mode humidity sensors were prepared using quartz-based SAW devices coated with composite sensing layers of accordion-like Ti3C2Tx, MoS2 nanoflowers and MoS2 @Ti3C2Tx hierarchical structure, respectively. The hydrophilic Ti3C2Tx was used to provide abundant surface functional groups for adsorption of water molecules, and the hydrophobic MoS2 enabled rapid adsorption and desorption of water molecules from the surface of MoS2 @Ti3C2Tx. The MoS2 @Ti3C2Tx coated Love wave humidity sensor presented an ultra-high sensitivity of 0.67 kHz/% RH in the wide humidity range from 11.3% RH to 97.3% RH, mainly attributed to the hierarchical structure of MoS2 @Ti3C2Tx with large specific surface areas, abundant adsorption sites and superhydrophilicity. Meanwhile, this Love wave humidity sensor showed fast response/recovery rates, great repeatability and long-term stability, indicating its great prospects in humidity detection applications.