Luminescence features of Mn2+-doped Zn2SiO4: A green color emitting phosphor for solid-state lighting

초록

A series of green-emitting Zn2-xSiO4:xMn (0.005 <= x <= 0.075) powder phosphors have been fabricated using a sol-gel procedure. XRD confirms the phosphors crystalline willemite structure of Zn2SiO4 with rhombohedral lattices. Following diffuse reflectance spectrum, E-g =4.04 eV and E-g =2.9 eV for direct and indirect allowed transitions for the Zn1.955SiO4:0.045 Mn phosphor was computed, respectively. Upon excitation at 255 nm, photoluminescence (PL) spectra display intense 522 nm green emission corresponding to T-4(1) -> (6)A(1) transition. As Mn2+ ion concentration increases, PL intensity enhances up to 0.045 mol of Mn2+ ions in Zn2SiO4 phosphor and then decreases beyond this concentration. The CIE chromaticity coordinates recorded for the optimized phosphor appear in green region of the CIE diagram. The electron paramagnetic resonance spectra recorded for phosphor show sextet hyperfine structure around g approximate to 2.0. Mn2+ ions are tetrahedrally coordinated in the structure. The PL results indicated that the prepared phosphor could be a suitable candidate as a green light emitting phosphor for display devices.

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