Facile fabrication of flower-like MoS2/nanodiamond nanocomposite toward high-performance humidity detection

A flower-like molybdenum disulfide (MoS2)/nanodiamond (ND) nanocomposite was successfully prepared via an easy hydrothermal synthesis method and fabricated into humidity sensors to investigate its humidity sensing characteristics. The morphological, nanostructural, and compositional characteristics of the prepared MoS2/ND nanocomposite were characterized by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), confirming that the MoS2/ND nanocomposite was successfully prepared. The experimental results demonstrate the MoS2/ND composite film sensor has high sensitivity as compared to pure MoS2 based humidity sensor, which could be ascribed to the formed 3D hierarchical structure of MoS2/ND nanocomposite. Meanwhile, the sensor exhibits good repeatability, rapid response, and low hysteresis. Moreover, the detailed humidity sensing mechanism was analyzed and discussed using complex impedance spectra and bode plots. Based on good sensitivity and rapid response, the sensor was employed to control the different degree of brightness of LED with non-contact sensing method via monitoring water evaporation on the skin, which could provide a potential and more advantageous method to control the brightness of display screen, such as cellphone and computer screens.