A Nanostructure Phosphor: Effect of Process Parameters on the Photoluminescence Properties for Near-UV WLED Applications.

The sol-gel preparative method was employed to synthesize SrZnSiO:Eu nanostructure phosphors for white-light emitting diodes. The effects of calcination temperature and atmosphere as two important process parameters on the structural, morphological and optical properties were investigated using comprehensive characterization methods such as X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM) and photoluminescence spectra. The obtained phosphors are efficiently excited from 340 to 400 nm, which matches the near UV emitting InGaN chip and emits strong band peaking at 481 nm due to 4f 5d( D) → 4f( S) transition of Eu ions. In this europium-doped host lattice, a partial reduction of Eu to Eu at high temperature during the synthesis in air according to the charge compensation model is perceived. Furthermore, for this sample forbidden f-f transitions of Eu are observed. Finally, using Scherrer's equation the crystallite size of the optimum products with color coordination of x = 0.176, y = 0.193 is estimated at ~30 nm, which was consistent with TEM observations. [ABSTRACT FROM AUTHOR]