Preparation and luminescence properties of broadband red-emitting Sr₃LiSbO₆: Mn⁴⁺, Sm³⁺ phosphor

A series of Sr₃LiSbO₆: Mn⁴⁺ and Sr₃LiSbO₆: Mn⁴⁺, Sm³⁺ red phosphors were synthesized using the high-temperature solid-state method. The phase, luminescence properties, and thermal stability of these phosphors were thoroughly investigated. The Sr₃LiSbO₆: Mn⁴⁺ phosphors exhibited a strong far-red emission band ranging from 650 to 750 nm centered at 693 nm, which is attributed to the ⁴E_2g → ⁴A_2g transition of Mn⁴⁺. To further broaden the emission spectra of the Sr₃LiSbO₆: Mn⁴⁺ phosphors, doping with Sm³⁺ ions as a co-activator was performed. The Sr₃LiSbO₆: Mn⁴⁺, Sm³⁺ phosphors exhibited two emission bands located at 601 nm and 693 nm (red and far red), which are well-matched with the absorption bands of phytochromes Red (P_R) and phytochromes Far-Red (P_FR). Additionally, the emission intensity and thermal stability of the phosphors were improved. Sr₃LiSbO₆: Mn⁴⁺ emits far-red light in the range of 650 nm-750 nm, while Sr₃LiSbO₆: Mn⁴⁺, Sm³⁺ emits red light in the range of 500 nm-750 nm. In the context of Sr₃LiSbO₆: Mn⁴⁺, Sm³⁺, we designed a LED lamp for plant growth and carried out experiments on plant seed germination. The findings from these experiments demonstrate the positive impact of red LEDs on plant growth and development. Additionally, our results suggest the potential application of red phosphors with Sr₃LiSbO₆: Mn⁴⁺, Sm³⁺ in plant growth.