Large-scale synthesis of highly pure Cd metal hexagonal nanosheets

Highly pure and large-scale single crystalline cadmium (Cd) metal hexagonal nanosheets with 10-12 nm thickness were obtained by catalyst-free thermal decomposition of cadmium oxide (CdO) powder under nitrogen gas at 1000 °C. The as-prepared product was characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction. Room temperature photoluminescence (PL) spectrum for Cd nanosheets exhibited three very distinct emission bands at 360 nm, 402 nm and 426 nm. UV emission band at 360 nm is attributed to radiative recombination of electrons in the s, p conduction band near the Fermi surface and the holes in the d bands generated by xenon light excitation whereas visible emission bands at 402 nm and 426 nm may be due to surface oxidation effects or induced defects in the nanosheets. The growth mechanism for the formation of Cd metal hexagonal nanosheets is also proposed and discussed briefly.