Facile synthesis of hierarchical SnO2 twig-like microstructures and their applications in humidity sensors

In this paper, the hierarchical SnO2 twig-like microstructures have been successfully synthesized by a facile hydrothermal reaction at 160 °C for 6 h with adding polyethylene glycol 6000 (PEG 6000). The prepared SnO2 architectures were characterized by X-ray powder diffraction (XRD) and Scanning electron microscopy (SEM). The branches of the prepared twig-like SnO2 architectures have a diameter of about 2-5 µm. The morphologies and sizes of as-prepared SnO2 architectures could be tailored by varying reaction time and temperature. Further, the synthesized SnO2 microstructures were applied to humidity sensors. The sensing test revealed that the twig-like SnO2 microstructures exhibit excellent humidity sensing performance at room temperature. Furthermore, the growth mechanism of the as-prepared hierarchical SnO2 microstructure was also proposed in this study.