Luminescence and energy transfer in Ca ₃Sc ₂Si ₃O ₁₂:Ce ³⁺,Mn ²⁺ white LED phosphors

Expanded emission spectra ranging from green to red are reported in Ca ₃Sc ₂Si ₃O ₁₂ (CSS):Ce ³⁺,Mn ²⁺ silicate garnets. Mn ²⁺ may occupy Ca ² site (Mn ²⁺(I)) to generate a yellow emission band at 574 nm or Sc ³ site (Mn ²⁺(II)) with red emission band at 680 nm. Efficient energy transfers from the green emitting Ce ³⁺ to both Mn ²⁺(I) and Mn ²⁺(II) occur upon blue excitation into Ce ³⁺. Concentration dependence of Mn ²⁺ emission is analyzed based on Ce ³⁺-Mn ²⁺ energy transfer, steady state rate equations, and fluorescence lifetimes. Energy transfer efficiency (η _T) and rate (W) are calculated with values as high as 45% and 14.01×10 ⁶ s ^-1, respectively.