Research Progress on Humidity-Sensing Properties of Cu-Based Humidity Sensors: A Review

Novel humidity sensors based on semiconducting metal oxides with good humidity-sensing properties have attracted extensive attention, which due to their high sensitivity at room temperature, high safety, low hysteresis, and long-term stability. As a typical p-type semiconductor metal oxide, CuO is considered to be a high-performance moisture-sensitive material; however, with the development of production, the complex working environment has put forward higher requirements for its humidity sensitivity, especially sensitivity and stability. In this regard, workers around the world are working to improve the moisture-sensing properties of sensing elements. In this review, the humidity-sensing properties of CuO-based moisture-sensitive materials are comprehensively summarized, focusing on effective measures to improve the moisture-sensing properties of CuO-based moisture-sensitive materials, including surface modification and nanocomposites. The future research of semiconducting metal oxide humidity-sensitive materials is also prospected.