Luminescence and Energy Levels of Mn²⁺ in LnMB₅O₁₀ (Ln=La, Gd and Y; M=Mg, Zn and Cd)

Abstract

Luminescence of Bi 3+ or/and Mn 2+ in LnMB 5 O 10 system of phosphor has been studied. Bi 3+ in LnMB 5 O 10 leads to two types of emissions, viz. emission due to (i) Bi 3+ isolated centres and (ii) Bi 3+ clusters. In LaMB 5 O 10 , Bi 3+ emission can cover longer distances (25 Å) for resonant transfer. In LaMgB 5 O 10 , replacement of Mg by Cd or Zn leads to considerable enhancement in Mn 2+ emission intensity. In the case of GdMB 5 O 10 system, this substitution leads to significant increase in the Gd 3+ →Mn 2+ energy transfer rate. Energy levels of Mn 2+ in LaMB 5 O 10 and crystal field parameters (for the case of cubic field) have been calculated and the results based on these are discussed.