Preparation of ZnO Microstructures by Facile Hydrothermal Route, Their PL and PEC Properties

ZnO flower like and doubly pointed microneedles (DPNs) were prepared on Cu2O and glass substrates respectively via facile hydrothermal route. Cu2O substrate was prepared through thermal oxidation method from the Cu sheet. The structure and morphologies of ZnO microstructures were characterized by X-ray diffraction and scanning electron microscopy. The average size of flower-like structure was measured to be 2 μm, whereas the doubly pointed microneedles (DPNs) exhibited a tip diameter of 150-250 nm. The flower-like ZnO microstructures showed the photoluminescence emission spectra UV band at 383 nm along with a strong yellow emission band at 580 nm. Correspondingly, the DPNs ZnO microstructure showed UV emission peak at 396 nm associated with a blue emission peak at 469 nm. The photon-to-hydrogen efficiency was found to be 0.04% for flower like microstructure.