The shape of the particles was studied with a field-emission low voltage electron microscope (SEM, Zeiss Sigma HDVP) operated at a 3 kV acceleration voltage. The morphology of the particleswas analyzed with a transmission electron microscopy (TEM, Philips CM-200 FEG/ STEM) operated at 200 kV. For SEM analysis, dry powder samples were placed on the Stubs (AGG301 SEM Specimen Stubs, Zeiss Instruments) using graphite glue. For TEM analysis, the holey carbon copper grid (S147-400 Holey Carbon Film 400 Mesh Cu grid, Agar Scientific) was immersed in the ethanol suspension of the particles and let dry before the measurements.