Abstract
In the study, a two-step high temperature solid state reaction method was applied to synthesize the green and green-yellow phosphors of 0.5 mol% Eu2+ doped Ba2SiO4, mixture of Ba3Si6O9N4 and Ba2SiO4, CaSi2O2N2. X-ray diffraction (XRD), scanning electron microscope (SEM), diffuse reflection (DR) spectra, photoluminescence (PL) excitation and emission spectra, thermal stability behavior, and luminescent decay curves were employed to analyze these phosphors. In the first step reaction, Eu3+ present weak red or orange-red emission. After reduction from Eu3+ to Eu2+ in the N2(95%)–H2(5%) atmosphere in the second reaction step, the Eu2+ presented bright green or green-yellow light under near ultraviolet (NUV) excitation. By combining the phosphors with NUV chips, the obtained LEDs gave bright light under forward bias current. The obtained green and green yellow materials can be used in phosphor converted based LEDs.
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