Microstructures and photoluminescence properties of three-dimensional multi-layered ZnO flowers by surfactant-free hydrothermal method

In this paper, a large-scale of three-dimensional multi-layered ZnO flowers constructed by porous nanosheets were fabricated on Zn foils through a surfactant-free hydrothermal method. The morphology and microstructures of precursors and the mesoporous ZnO flowers were revealed by scanning electron microscopy. Based on the urea hydrolyzation, a possible growth mechanism of etching-deposition was proposed. The quantities and sizes of ZnO petals can be turned by urea concentration variations. The optical properties of the multi-layered ZnO flowers prepared with variety urea contents were also investigated by room temperature photoluminescence spectroscopy and showed the lower urea added sample has better crystalline quality.