Tunable blue-green-emitting Ca3Si2O4N2:Ce3+, Eu2+ phosphor with energy transfer for light-emitting diodes

Abstract

A series of Ce³⁺, Eu²⁺ codoped Ca₃Si₂O₄N₂ phosphors have been synthesized by traditional solid state reactions, and the crystal structures and luminescence properties were investigated in detail. Rietveld structure refinement indicates that Ca₃Si₂O₄N₂ crystallizes in a cubic unit cell with space group Pa(205) and lattice constant a = 15.0712 Å. Tunable blue-green emitting Ca₃Si₂O₄N₂:Ce³⁺, Eu²⁺ phosphors have been obtained by codoping Ce³⁺ and Eu²⁺ into the host and varying their relative ratios. Compared with the Eu²⁺ ion singly doped phosphor, the codoped phosphors have wider absorption in the ultraviolet (UV) range and stronger emission of Eu²⁺, which are attributed to the effective energy transfer from Ce³⁺ to Eu²⁺. The energy transfer from Ce³⁺ to Eu²⁺ is demonstrated to be a dipole–dipole mechanism. The Ce³⁺, Eu²⁺ codoped phosphors might be candidates for blue-green components in UV white light-emitting diodes (WLEDs).