Synthesis and photoluminescence of hollow microspheres constructed with ZnO nanorods by H2 bubble templates

The ZnO nanorod-based hollow microspheres have been prepared via a simple hydrothermal reaction of [Zn(NH3)4]2+ with KBH4 at 140 °C for 8 h using Zn(CH3COO)2 · 2H2O, ZnSO4 · 7H2O or Zn (NO3)2 · 6H2O as the Zn source. The hollow microspheres with the diameters of 2–4 μm are constructed from ZnO nanorods with the hexagonal wurtzite structure and diameter of about 100 nm. A possible mechanism was proposed to account for the formation of hollow ZnO nanorod-based microspheres. Phonon replicas associated with 2-E2 phonon are observed in the PL spectrum from the ZnO superstructures.