Study on the preparation and luminescence properties of SrGe4O9:Mn4+ red phosphors for plant illumination

In this study, SrGe₄O₉:Mn⁴⁺ red phosphors for plant illumination were prepared using a high-temperature solid-phase method. The samples were characterized and analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fluorescence spectroscopy, and other techniques. The phase structure, apparent morphology, and luminescence properties of the SrGe₄O₉:Mn⁴⁺ red phosphors were investigated. The results indicated that the dopant Mn⁴⁺ was incorporated into the matrix structure by substituting some Ge⁴⁺ ions without any changes in the crystal structure of the SrGe₄O₉ matrix. The samples comprised micron-scale particles and exhibited high purity and uniform distribution of elements. The SrGe₄O₉:Mn⁴⁺ phosphors exhibited relatively strong red light emission at 660 nm under the excitation of a 430-nm blue light, and the luminescence intensity was the highest when the Mn⁴⁺ doping amount was 1%. Proper doping of Ti⁴⁺ or Sn⁴⁺ could effectively improve the luminescence intensity of the SrGe₄O₉:Mn⁴⁺ phosphors. The light-emitting diode (LED) device packaging showed that the SrGe₄O₉:Mn⁴⁺ red phosphors could be used for plant growth illumination.