Synthesis and White Light Emission of Rare Earth-Doped HfO_2 Nanotubes

摘要

Luminescent nanotubes based on rare earth (RE) (Eu, Tb)-doped hafnia (HfO_2) were prepared by radio frequency (RF) sputtering with electrospun polyvinylpyrolidone (PVP) nanofi-bers as templates. The nanotubes annealed at 500 C have a uniform structure with desired tubular morphologies. Various colors of photoluminescence (PL) could be easily obtained by tuning the concentrations of the RE ions in the HfO_2 host. The Eu- and Tb-codoped HfO_2 (HfO_2:Eu&Tb) nanotubes exhibited white light emissions under a 325 nm excitation. Good Commission International de I'Eclairage (CIE) coordinates (0.333, 0.323) and color temperature (T_c) (5465 K) were achieved in the HfO_2:Eu&Tb nanotubes. Experimental evidence showed that the presence of blue emission originates from the defect states in HfO_2 nanotubes, the green and the red emissions can be attributed to the inner 4f shell transitions of corresponding Tb~(3+) ions and Eu~(3+) ions in FHO_2 shells, respectively. Compared with RE-doped HfO_2 films, the nanotube samples showed intense white light emissions, revealing that the HfO_2:Eu&Tb nanotubes are an efficient white light-emission material.