Ultraviolet-assisted synthesis of hourglass-like ZnO microstructure through an ultrasonic and microwave combined technology

Well-defined hexagonal hourglass-like ZnO microstructures have been synthesized by using simultaneous ultrasound and microwave irradiation methods with the assistance of ultraviolet as well as double sonication (at 25 and 40 kHz). The structure and morphology of as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy and photoluminescence spectrum. The results show the synergistic effect of ultrasound and microwave on the formation of ZnO microstructures. Meanwhile, the possible growth mechanism was proposed to elucidate the formation of hexagonal hourglass-like ZnO microstructures.