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 Mn 4+ - and Mn 4+ /Ca 2+ -doped double perovskite SrGd 2 Al 2 O 7 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 SrGd 2 Al 2 O 7 for a better understanding of the luminescence behavior in this material. Extensive analysis demonstrates that the introduction of Ca 2+ ions into the SrGd 2 Al 2 O 7 :Mn 4+ 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 Mn 4+ -based far-red phosphors. The mechanism of the concentration quench effect and the positive effect of co-doping Ca 2+ ions in the phosphor were extensively explored. All studies suggest that the SrGd 2 Al 2 O 7 :0.1%Mn 4+ , 11%Ca 2+ 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.