Synthesis of High-Density Poinsettia-Like Microstructure of CuO by the Hydrothermal Method and Its Ethanol Sensing Properties

Highly uniform and dense poinsettia-like microstructures of CuO were synthesized by a facile hydrothermal method. The effect of the treatment time on the growth of the CuO microstructures was investigated. The CuO microflowers with diameters in the range 3–5 μm were composed of many interconnected nanoleaves (1–2 μm in diameter and 20–30 nm in thickness). A plausible growth mechanism for the formation of the CuO microstructures has been proposed and discussed. In addition, the ethanol sensing properties of the CuO microflowers were characterized at 150–350°C. The poinsettia-like microstructures of CuO exhibited better response to ethanol when compared to the sensing properties of the CuO nanoleaves. The sensing mechanism based on the models of carrier transport and leaf-to-leaf contact has been proposed and discussed.