Mn2+-Eu3+-Dy3+ doped and co-doped Zn2SiO4 nanophosphors: Study of the structure, photoluminescence and surface properties

Zinc silicate (Zn2SiO4) nanophosphor, doped with manganese (Mn2+) and co -doped with europium (Eu3+) and dysprosium (Dy3+) were synthesized by sol-gel method. In this work the structure, surface and photoluminescence properties of Zn2SiO4: Mn2+, Eu3+, Dy3+ nanophosphor were studied. A broad diffraction peak revealed by X-ray diffraction indicated an amorphous phase of the nanophosphor. However, the crystallinity improved with annealing temperature of 1100 degrees C and the crystallite phase corresponding to alpha-Zn2SiO4 was observed. Upon UV-excitation by a xenon lamp, photoluminescence (PL) spectra of singly doped Zn2SiO4 were also analyzed. Zn2SiO4: Mn2+ revealed a green emission at 520 nm, corresponding to the T-4(1)(4G) (6)A(1)(6S) electronic transition of Mn2+. Zn2SiO4: Eu3+ showed a prominent emission band at 615 nm, corresponding to D-5(0) > F-7(2) transition of Eu3+ ions and Zn2SiO4: Dy3+ showed two prominent emission bands located at 481 and 578 nm corresponding respectively to the F-4(9/2) -> H-6(15/2) and F-4(9/2) -> H-6(13/2) transitions of Dy3+. Scanning electron microscopy (SEM) coupled with Energy dispersive spectroscopy (EDS) were used to study the morphology and elemental composition of the Zn2SiO4: Mn2+, Eu3+, Dy3+ nanophosphor. The CIE calculated from the emission spectra showed coordinates which varied from green, orange to red through white with the change of dopant in Zn2SiO4 host lattice. Therefore, Zn2SiO4: Mn2+, Eu3+, Dy3+ nanophosphor is a potential material for application in UV -pumped multicolor and white light emitting diodes. The surface analysis of Zn2SiO4 nano phosphor was performed by using X-ray Photoelectron Spectroscopy (XPS).