The sensitized luminescence and tunable color of single-component Sr2MgSi2O7:Bi3+/Sm3+/Tb3+ phosphor via energy transfer for white-light emitting diodes

Abstract A series of single-phase blue-to-red tunable-color emitting and excellent green-emission Sr 2 MgSi 2 O 7 :Bi 3+ , Sm 3+ /Tb 3+ phosphors have been synthesized by high temperature solid state reaction. The crystal structure of Sr 2 MgSi 2 O 7 and the crystallographic sites of Bi 3+ , Sm 3+ and Tb 3+ ions in the host have been identified through the crystallographic data from Rietveld refinements. The luminescent properties of Sr 2 MgSi 2 O 7 :Bi 3+ /Sm 3+ /Tb 3+ phosphors were investigated and the Bi 3+ , Sm 3+ or Tb 3+ single doped samples exhibit blue, orange-red and green emissions, originating from the 3 P 1 → 1 S 0 transition of Bi 3+ , the 4 G 5/2 to 6 H J (J = 5/2, 7/2, 9/2) transitions of Sm 3+ and the 5 D 4 → 7 F J (J = 6, 5, 4, 3) multiplet transitions of Tb 3+ , respectively. Meanwhile, the energy migration from Bi 3+ to Sm 3+ and Tb 3+ in co-doping samples was confirmed by emission/excitation spectra and luminescent decay behaviors. The mechanism of energy transfer from Bi 3+ to Sm 3+ has been demonstrated to be the resonant type via a dipole–dipole interaction and the critical distances between Bi 3+ and Sm 3+ were calculated to be 22.28 A. Additionally, the temperature-dependent photoluminescence for as-prepared phosphors have been investigated in detail. The luminescence intensity of Sm 3+ and Tb 3+ ions can be sensitized to enhance by Bi 3+ ion. The blue and orange-red colors can be tuned by adjusting the concentration ratio of Bi 3+ /Sm 3+ base on the energy transfer from Bi 3+ to Sm 3+ ions, and the phosphors Sr 2 MgSi 2 O 7 :Bi 3+ , Tb 3+ develop excellent green-emission properties, which indicate that the Sr 2 MgSi 2 O 7 :Bi 3+ , Sm 3+ /Tb 3+ phosphors with tunable multicolor and green emissions may be of potential application in pc-white LEDs.