Enhanced deep-red luminescence in Ba2-Sr GdSbO6: Mn4+ phosphors via cation substitution for plant-growth LEDs

• By employing a Sr 2+ cation substitution strategy, the luminescence intensity of Ba 2 GdSbO 6 : Mn 4+ phosphor was enhanced by nearly 12-fold. • LED devices based on optimal sample preparation exhibit electroluminescence spectra that closely match plant pigment absorption bands, making them highly targeted for specific applications. • This provides a practical cation substitution strategy for the design and development of novel Mn 4+ -doped double perovskite phosphors. Mn 4+ -doped oxide phosphors with deep-red emission show significant application potential in plant-growth LEDs. In this study, double perovskite Ba 2- x Sr x GdSbO 6 : Mn 4+ deep-red phosphors were developed via a cation substitution strategy. The crystal structure, optical properties, and thermal stability of the phosphors were investigated in detail. The as-prepared phosphors showed an intense deep-red emission band around 625–750nm. Cationic substitution with Sr 2+ significantly improved the luminescence performance of the Ba 2 GdSbO 6 : Mn 4+ phosphors, and the optimized sample BaSrGdSbO 6 : Mn 4+ was obtained, achieving a nearly 12-fold enhancement in emission intensity. Furthermore, the electroluminescence (EL) spectrum of the prototype LED device fabricated based on the BaSrGdSbO 6 : Mn 4+ phosphor is matched well with the absorption band of plant pigments. These findings demonstrate that the BaSrGdSbO 6 : Mn 4+ phosphors have potential applications in plant-growth LEDs, and also provide some guiding inspirations in the exploration of novel Mn 4+ -doped double perovskite phosphors.