Ultrahigh Response Humidity Sensor Based on Lead-Free Cs<sub>2</sub>SnCl<sub>6</sub> Perovskite Films
Qijie Chang, Daofu Wu, Yanyi Huang, Chengyao Liang, Libo Liu, Huanbin Liu, Yan Liu, Jing Qiu, Xiaosheng Tang, Genquan Han
Abstract
The humidity sensor based on quartz crystal microbalance (QCM) has a remarkable advantage for Internet of Things (IoT) applications owing to its digital output. Herein, one lead-free perovskite Cs <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> SnCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> film is employed to manufacture a QCM-based humidity sensor, and the practical application on IoT is successfully performed. The fabricated humidity sensor exhibits a logarithmic linearity response and an ultra-high response of 7289 Hz for the relative humidity ranging from 11% to 85%. Furthermore, the Langmuir adsorption model is adopted to reveal the adsorption kinetics of the water molecules on the Cs <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> SnCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> film. These results suggest that the proposed humidity sensor could be a promising candidate for remote and smart humidity sensors.