Effective red compensation of Sr 2SiO 4: Dy 3+ Phosphor by Codoping Mn 2+ ions and its energy transfer

Abstract

Mn 2+ ions codoped Sr 2SiO 4: Dy 3+ phosphors were prepared by the solid-state reaction method using NH 4Cl as the flux. Their phase compositions, photoluminescence properties, and the energy transfer process were systematically investigated. All Mn/Dy codoped powders were α ′-Sr 2SiO 4. The codoping concentration range of Mn 2+ was ≤ 4.0 mol to keep the structure undamaged. The broad red emission of Mn 2+ centered at 647 nm in Sr 2SiO 4: Mn, Dy powders, which effectively compensated the red emission of Sr 2SiO 4: Dy 3+ phosphor. The CIE chromaticity coordinates dramatically changed from (0.310, 0.340) to (0.332, 0.326) due to the red enhancement via the energy transfer from Dy 3+ to Mn 2+. This energy transfer is realized by the exchange interaction. But the luminescence quenching of Sr 2SiO 4: Dy, Mn phosphor was mainly caused by the electric multipoles interaction. The concentration optimized (Sr 0.96, Mn 0.02, Dy 0.02) 2SiO 4 phosphor with high and almost pure white emission has great potential to act as a single-matrix white phosphor for white LEDs. © 2012 Le Zhang et al.