Improvement of light emission of Mn-doped Zn(2) SiO(4) phosphors with sodium

Mn‐doped willemite (Zn₂SiO₄:Mn) green phosphor were synthesized by sol–gel technology. The effect of the addition of sodium, as in the composition Zn_{(1.92 – X)} Na_XMn_0.08SiO₄, on the emission behavior was studied. FT–IR and EPR results revealed that sodium ion is incorporated into the lattice and results in the formation of isolated Mn²⁺ and Mn–Mn pairs. The maximum emission intensity of the sample under ultraviolet (UV) excitation occurred at the sodium concentration of x = ~0.03. The green emission at about 525 nm is assigned to Mn²⁺–Mn²⁺ pair centres on nearest neighbour Zn sites. The highest intensity of the green emission for x = ~0.03 is well close to the highest concentration of the Mn²⁺–Mn²⁺ pair. Copyright © 2012 John Wiley & Sons, Ltd.