Ca2+ enhanced far-red emission performance and efficiency of SrGd2Al2O7:Mn4+ phosphor for the potential application in plant growth lighting.

Mn-based phosphors with the wavelength of 700–750 nm are an important category of far-red phosphors that have promising potential in the application of plant lighting, and the higher ability of the far-red light emitting of the phosphors is beneficial to plant growth. Herein, a series of Mn⁴⁺- and Mn⁴⁺/Ca²⁺-doped double perovskite SrGd₂Al₂O₇ red-emitting phosphors with wavelengths centered at about 709 nm were successfully synthesized by means of a traditional high-temperature solid-state method. First-principles calculations were conducted to explore the intrinsic electronic structure of SrGd₂Al₂O₇ for a better understanding of the luminescence behavior in this material. Extensive analysis demonstrates that the introduction of Ca²⁺ ions into the SrGd₂Al₂O₇:Mn⁴⁺ phosphor has significantly boosted the emission intensity, internal quantum efficiency, and thermal stability by 170%, 173.4%, and 113.7%, respectively, which are superior to those of most other Mn⁴⁺-based far-red phosphors. The mechanism of the concentration quench effect and the positive effect of co-doping Ca²⁺ ions in the phosphor were extensively explored. All studies suggest that the SrGd₂Al₂O₇:0.1%Mn⁴⁺, 11%Ca²⁺ phosphor is a novel phosphor that can be used to effectively promote the growth of plants and regulate the flowering cycle. Therefore, promising applications can be anticipated from this new phosphor. [ABSTRACT FROM AUTHOR]