Bi3+/Mn4+ co-doped dual-emission phosphors for potential plant lighting

Developing environment-friendly dual-emission phosphors of both blue–cyan and deep-red lights is desirable for the utilized indoor plant lighting research. Notably, the naked 6s and 6p Bi 3+ ions are sensitive to the lattice sites, which emit from Ultraviolet (UV) to red lights in various crystal compounds. Meanwhile, the 2 E → 4 A 2g transition of Mn 4+ ions promises its deep-red light emissions, which satisfies the demand for specific wavelength lights for plants growth. Hence, a Bi 3+ /Mn 4+ co-doped Sr 2 LaGaO 5 : Bi 3+ , Mn 4+ (SLGO:Bi 3+ :Mn 4+ ) phosphor was finally synthesized. The phase, micromorphology and luminescent properties were systematically evaluated. Upon excitation at 350 nm light, dual emissions of both blue–cyan (470 nm) and deep-red (718 nm) lights were observed. Besides, due to the pronounced photoluminescence (PL) spectral overlap between Bi 3+ and Mn 4+ ions, a potential energy transfer process from Bi 3+ to Mn 4+ ions was confirmed. The relative PL intensities between Bi 3+ and Mn 4+ ions can be tuned just by adjusting the Mn 4+ ion concentration. Besides, Li + co-doping has been evidenced to improve the deep-red emissions (718 nm) of SLGO:0.005Mn 4+ due to charge compensation and rationally designed lattice distortion, together with the improved thermal stability. Finally, the emissions of SLGO:Bi 3+ , Mn 4+ , Li + phosphor suit properly with the absorption of the four fundamental pigments for plant growth, indicating that the prepared phosphorescent materials may have a prospect in plant light-emitting diodes lighting.