Synthesis, crystal structure, and luminescence properties of a novel green emitting phosphor Na2Mg1-xSiO4:Mnx2+

In this paper, a novel green phosphor Na2Mg1-xSiO4:xMn2+ (x = 0.02, 0.04, 0.06, 0.08, 0.10, 0.12, 0.15, 0.20) was successfully synthesized by a traditional solid-state reaction method at 950 °C. The powder X-ray diffraction (PXRD), the photoluminescence excitation and emission spectra (PL and PLE) were measured to systematically study the as-prepared phosphors. The as-obtained Na2MgSiO4:Mn2+ phosphor shows an intense asymmetric green emission spectra with the broad-band peak at 520 nm due to 4T1(4G) → 6A1(6S) transition of the Mn2+ ion. The optimum Mn2+ concentration in this phosphor was 8 mol%. The MnMn critical distance was calculated to be 13.42 Å. The dipole-dipole interaction dominates in the non-radiative energy transfer between the Mn2+ ions and causes the concentration quenching. The decay curve of the Na2MgSiO4:Mn2+ phosphors were discussed. The CIE chromaticity coordinate values (x = 0.163, y = 0.631) of Na2MgSiO4:0.08Mn2+ phosphor were located in green region and the correlated color temperature was 8643 K. The above results indicate that Na2MgSiO4: Mn2+ as a green component can be a good candidate for near UV-excited w-LEDs.