Fabrication of leaf shaped SnO2 nanoparticles via sol–gel route and its application for the optoelectronic humidity sensor

Abstract In this report, synthesis of nanostructured SnO2 via sol–gel technique and its application for the detection of humidity level has been studied. Scanning electron microscopy (SEM) micrographs showed the formation of uniform leaf like structured SnO2 nanoparticles. The average crystalline size is discovered as 9 nm calculated by Debye Scherrer’s formula using X-ray diffraction (XRD) which shows tetragonal crystal structure. The crystallite size is further confirmed by transmission electron microscopy (TEM). The optical band gap is estimated as 3.63 eV by UV–Visible absorption spectra. The prepared SnO2 based thin film with leaf like structure enhances the feasibility for the detection of humidity, especially in the high range of 65–90 %RH. The prepared SnO2 samples shows good sensitivity towards the relative humidity. It shows 1.8nW/% RH in the humidity range 65–90% RH at 25 °C.