Emission enhancement of LiLaMo2O8:Eu3+ phosphor by co-doping with Bi3+ and Sm3+ ions

A series of LiLaMo 2 O 8 :Eu 3+ , R (R = Bi 3+ and Sm 3+ ) phosphors are synthesized by a high temperature solid-state reaction method in air. The crystal structures, fluorescence lifetimes , and luminescence properties are investigated in detail. LiLaMo 2 O 8 :Eu 3+ phosphor with excitation 395 nm shows red light in the range of 525–725 nm and it photoluminescence intensity may be enhanced ∼2.35 times due to energy transfer (ET) from a sensitizing species (Bi 3+ or Sm 3+ ) to Eu 3+ ion after Bi 3+ or Sm 3+ ion is co-doped. The optimal Eu 3+ , Bi 3+ , and Sm 3+ ion concentrations are 4%. Luminous mechanism of LiLaMo 2 O 8 :Eu 3+ , R (R = Bi 3+ and Sm 3+ ) phosphors and ET processes between Eu 3+ and Bi 3+ /Sm 3+ ions are analyzed and explained by their excitation and emission spectra and energy level diagrams of Eu 3+ , Bi 3+ , and Sm 3+ ions. The experimental results indicate that LiLaMo 2 O 8 :Eu 3+ , R (R = Bi 3+ and Sm 3+ ) phosphors may be used as potenial red emitting materials for white light emitting diodes (LEDs) based on either a near ultraviolet (∼395 nm) or blue (∼465 nm) chip.