Enhanced luminescence of Sr<inf>2</inf>SiO<inf>4</inf>:Dy³⁺ by sensitization (Ce³⁺/Eu²⁺) and fabrication of white light-emitting-diodes

The role of sensitization by co-doping Ce3+/Eu2+ in the Sr2SiO4:Dy3+ phosphor system is studied with a view of improving the emission properties and chromaticity coordinates. The concentration dependence of the emission intensity of Dy3+ in Sr2-2xDyxLixSiO4: (x=0.01-0.05 in steps of 0.01) is studied, and the critical concentration is found to be 3 mol% Dy3+ per formula unit. Partial energy transfer from Ce3+ to Dy3+ is observed, and the luminescence intensity of Dy 3+ is enhanced. It is also found that Eu2+, Ce 3+ containing compositions show better white emission than the corresponding Sr2SiO4:Dy3+. LEDs fabricated by coating the ultraviolet (UV) emitting chips with the synthesized phosphor compositions show bright white emission with reasonable chromaticity coordinates. © 2013 Elsevier B.V.