Structural, morphological, and optical properties of double-ended needle-like ultra-long ZnO micro/nanorods

An environmentally benign hydrothermal route was used to synthesize ultra-long double-ended needle-like ZnO microrods. The microrods were morphologically uniform with a diameter of around 1–2 µm, and a length of 40–50 µm. The rods were grown directly from an aqueous alkaline solution containing Zn(OH) 4 2− ions, produced from ZnSO 4 and NaOH, without using any structure-directing reagent. The products were characterized using x-ray diffraction, energy-dispersive x-ray analysis, scanning electron microscopy, ultraviolet–visible spectrophotometry, and photoluminescence, and the results are reported. The influence of the preparation parameters on the morphology of the ZnO products is also discussed.