Fabrication of highly sensitive and fast response flexible humidity sensor based on GOQDs/WS₂ composite film

In this work, a fabrication of highly sensitive and fast response flexible humidity sensor based on GOQDs/WS₂ hybrid thin film was proposed. The humidity sensing thin film of GOQDs/WS₂ composite was deposited on the flexible PI substrate via a facile drop-coating technique. The prepared humidity sensor has a responsivity of up to 99.5%, a response time of 2.5 s and a recovery time of 41.5 s, good repeatability, low hysteresis, and good long-term stability. The performance of GOQDs/WS₂-based humidity sensor is significantly improved compared to the pure WS₂-based humidity sensor, with a 25-fold improvement in response time. In addition, the humidity enhanced sensing mechanism was also discussed. This study demonstrates that the GOQDs/WS₂ composite film is a promising humidity sensing material with high sensitivity and fast response, which can be potentially used for humidity monitoring in flexible wearable devices.