Hollow microsphere assembly of ZnO nanosheets

Growth and assembly of ZnO nanosheets into hollow microsphere are performed using PEG 200 as directing agent. FESEM images show that the average width of these assemblied ZnO nanosheets is around ∼250 nm, the length is about 500-800 nm and the thickness is about 25 nm, the diameter of ZnO-assembled microsphere is about 2-4 μm. Study shows that microsphere of ZnO nanosheets have a centre cavity, these microsphere assemblied ZnO nanosheets have a wide visible yellow emission at 567 cm^-1, confocal laser microscopy of an individual ZnO nanosheets assemblied microsphere also show the intense yellow light emission. The oriented attachment of ∼5 nm ZnO nanoparticle building blocks eventually form the ZnO nanosheets. The most plausible dissociation-deposition mechanism that directs the formation of microspheric assembly of ZnO nanosheets is also proposed.