Synthesis and photoluminescence properties of self-assembled Eu-doped ZnO hollow microspheres

ZnO hollow microspheres with a shell wall consisting of crystalline ZnO nanosheets were synthesized by using Zn5(CO3)2(OH)6 microspheres as spherical templates. Zn5(CO3)2(OH)6 microspheres were first fabricated by a solvothermal procedure in an ethylene glycol (EG)water solution. ZnO microspheres with a hexagonal structure were identified by means of X-ray diffraction (XRD) and selected-area electron diffraction (SAED). On the basis of the results, a possible self-assembly growth mechanism was proposed. It reveals that the EG played an important role in determining the hollow morphologies of Zn5(CO3)2(OH)6 structures. In addition, photoluminescence (PL) investigation of ZnO:Eu3+ suggested that a direct energy transfer occurred, which was ascribed to the energy transfer from ZnO host to Eu3+ ions.