From ZnO nanorods to 3D hollow microhemispheres: solvothermal synthesis, photoluminescence and gas sensor properties

A novel solvothermal process using ethylene glycol (EG) as solvent has been employed to synthesize 3D ZnO hollow microhemispheres consisting of numerous orderly and radical nanorods with diameter of about 50 nm and length of several hundred nanometers. The glycol such as EG and the solvothermal process play the critical role in the synthesis of the 3D ZnO hollow microhemispheres by the primary formation of glycolate precursors and subsequent transformation into ZnO. The morphology, structure and optical property of the 3D ZnO hollow microhemispheres have been characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), x-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL). Furthermore, the 3D ZnO hollow microhemisphere based gas sensor exhibits high sensitivity for ethanol and ammonia as well as quick response and recovery time at room temperature due to the high surface-to-volume ratio.