Photoluminescence properties of Dy³⁺ activated Ca₂SiO₄ nanophosphor for WLED applications

ABSTRACT

A series of Dy³⁺-activated Ca₂SiO₄ phosphors were prepared by low-temperature solution combustion method. The obtained phosphor was well characterized by powder X-ray diffraction, scanning electron microscopy, UV–visible spectroscopy, etc. The average crystallite size was estimated using Scherer's formula and Williamson–Hall plots and was found to be in the range of 40–57 nm. The optical energy band gaps (E_g) for Dy-doped samples were estimated and were found to be in the range of 5.10–5.44 eV. The energy band gap was found to be widened with an increase of Dy³⁺ ion concentration. Photoluminescence spectra consist of three main groups of peaks in 460–500 nm (blue), 555–610 nm (yellow) and 677 nm (red) regions, respectively, and were assigned to the transitions of ⁴F_9/2 → ⁶H_15/2,_13/2,_11/2. The chromaticity color coordinates of all the prepared phosphors were found to be in the white region and was quite useful for the white light emitting diodes (WLED's).

KEYWORDS:

• Phosphor
• photoluminescence
• CIE
• CCT
• WLEDs