A novel Sm³⁺-activated Li₃BaSrLn₃(MO₄)₈ [Ln = La, Gd, and Y; M = Mo and W] deep red-emitting phosphors for plant cultivation and white LEDs

Figures & data

Figure 1. Powder XRD patterns of the Li₃BaSrLn_3−x(MoO₄)₈:_xSm³⁺ [Ln = (a) La, (b) Gd, and (c) Y] phosphor.

Figure 2. Powder XRD patterns of the Li₃BaSrLn_3−x(WO₄)₈:_xSm³⁺ [Ln = (a) La, (b) Gd, and (c) Y] phosphor.

Figure 3. (a and b) Crystal structure of the Li₃BaSrY₃(MoO₄)₈ phosphor, and (c) coordination of Ba, Y/Li(1), and Li(2) with oxygen.

Figure 4. SEM image of the Sm³⁺-activated Li₃BaSrLn₃(MoO₄)₈ [Ln = (a and b) La, (c and d) Gd, and (e and f) Y] phosphor.

Figure 5. SEM image of the Sm³⁺-activated Li₃BaSrLn₃(WO₄)₈ [Ln = (a and b) La, (c and d) Gd, and (e and f) Y] phosphor.

Figure 6. (a) FT-IR spectrum of the Li₃BaSrLn₃(MoO₄)₈ (Ln = La, Gd, and Y) and (b) Li₃BaSrLn₃(WO₄)₈ (Ln = La, Gd, and Y) phosphors.

Figure 7. PLE (LHS) and PL (RHS) spectra of the Li₃BaSrLn₃(MoO₄)₈:Sm³⁺ [Ln = (a and b) La, (c and d) Gd, and (e and f) Y] phosphor.

Figure 8. PLE (LHS) and PL (RHS) spectra of the Li₃BaSrLn₃(WO₄)₈:Sm³⁺ [Ln = (a and b) La, (c and d) Gd, and (e and f) Y] phosphor.

Figure 9. PL emission intensity of the ⁴G_5/2→⁶H_9/2 transition of the Li₃BaSrLn₃(MoO₄)₈:Sm³⁺ [Ln = (a) La, (b) Gd, and (c) Y] phosphor; and (d) overall emission intensity of the Sm³⁺-doped Li₃BaSrLn₃(MoO₄)₈ (Ln = La, Gd, and Y) phosphor.

Figure 10. PL emission intensity of the ⁴G_5/2→⁶H_9/2 transition of the Li₃BaSrLn₃(WO₄)₈:Sm³⁺ [Ln = (a) La, (b) Gd, and (c) Y] phosphor; and (d) overall emission intensity of the Sm³⁺-doped Li₃BaSrLn₃(WO₄)₈ (Ln = La, Gd, and Y) phosphor.

Figure 11. Relationship between log C and log (I/C) for the Li₃BaSrLn₃(MO₄)₈:Sm³⁺ [Ln = La, Gd, and Y; M = Mo (LHS) and W (RHS)] phosphors.

Figure 12. (a) Energy level diagram, and (b) cross-relaxation mechanism of the Sm³⁺ ion in the Li₃BaSrLn₃(MO₄)₈ lattice.

Figure 13. Schematic diagram of the energy transfer from MoO₄^2– to the Sm³⁺ ion.

Figure 14. Decay curve of the Sm³⁺-activated Li₃BaSrLn₃(MoO₄)₈ [Ln = (a) La, (c) Gd, and (e) Y] phosphor; and (b, d, and f) lifetime values of all the phosphors.

Figure 15. Decay curve of the Sm³⁺-activated Li₃BaSrLn₃(WO₄)₈ [Ln = (a) La, (c) Gd, and (e) Y] phosphor; and (b, d, and f) lifetime values of all the phosphors.

Figure 16. Temperature-dependent PLs of the Sm³⁺-activated Li₃BaSrLn₃(MoO₄)₈ phosphors [Ln = (a) La, (c) Gd, and (e) Y] and Arrhenius plot of the Li₃BaSrLn₃(MoO₄)₈ phosphors [Ln = (b) La, (d) Gd, and (f) Y].

Figure 17. Temperature-dependent PLs of the Sm³⁺-activated Li₃BaSrLn₃(WO₄)₈ phosphors [Ln = (a) La, (c) Gd, and (e) Y]; and Arrhenius plot of the Li₃BaSrLn₃(WO₄)₈ phosphors [Ln = (b) La, (d) Gd, and (f) Y].

Figure 18. Normalized intensity variations of the Li₃BaSrLn₃(MO₄)₈ [Ln = La, Gd, and Y; M = (a) Mo and (b) W] phosphors at different temperatures.

Figure 19. CIE images of the Sm³⁺-activated Li₃BaSrLn₃(MoO₄)₈:Sm³⁺ (Ln =  La, Gd, and Y) red-orange phosphors.

Figure 20. CIE images of the Sm³⁺-activated Li₃BaSrLn₃(WO₄)₈:Sm³⁺ (Ln =  La, Gd, and Y) red-orange phosphors.

Figure 21. IQE measurement for the optimized composition of the Sm³⁺-activated Li₃BaSrLn₃(MO₄)₈ (Ln = La, Gd, and Y; M = Mo and W) phosphors.

Figure 22. LED emission spectrum of the fabricated red-orange-emitting LED device from the combination of InGaN LED with the (a) Li₃BaSrLn₃(MoO₄)₈:Sm³⁺ (Ln = La, Gd, and Y) and (b) Li₃BaSrLn₃(WO₄)₈:Sm³⁺ (Ln = La, Gd, and Y) phosphors.

Figure 23. LED emission spectrum of the fabricated LED (Li₃BaSrY₃(WO₄)₈:Sm³⁺) and absorption of phytochrome Pr.