Synthesis, adjustable-color emission and energy transfer of Ba2MgSi2O7:Sm3+, Bi3+ phosphors

Ba2MgSi2O7:M (M = Bi 3+ , Sm 3+ , Sm 3+ /Bi 3+ ) phosphors are synthesized in air by the high-temperature solid-state reaction method. All samples are confirmed to be a pure phase. With a 316 nm excitation wavelength, Ba 2 MgSi 2 O 7 :Bi 3+ shows blue-white emission including a broad emission band in the range of 340 - 750 nm, and Ba 2 MgSi 2 O 7 :Sm 3+ , Bi 3+ emits a adjustable-color light with the change of the ratio of Sm 3+ to Bi 3+ ions. Under excited at 402 nm, Ba 2 MgSi 2 O 7 :Sm 3+ and Ba 2 MgSi 2 O 7 :Sm 3+ , Bi 3+ emit orange-red light with emission spectrum region from 545 nm to 750 nm, which contain four emission bands peaking at ∼560, 598, 646 and 704 nm due to the 4 G 5/2  →  6 H 5/2 , 6 H 7/2 , 6 H 9/2 , and 6 H 11/2 transitions of Sm 3+ ion, respectively. Ba 2 MgSi 2 O 7 :Sm 3+ , Bi 3+ under excitation at 316 nm can show a white-color emission by changing the ratio between Sm 3+ and Bi 3+ ions. Lifetimes of samples decrease with increasing doped ion (Sm 3+ or Bi 3+ ) concentration. We explain the luminous mechanism of samples by the schematic energy level diagrams of Bi 3+ and Sm 3+ ions in Ba 2 MgSi 2 O 7 :Sm 3+ , Bi 3+ .