Realization of highly efficient Ba2SrWO6:Mn4+ phosphor via La addition strategy and application for plant cultivation LED

Herein, a novel Ba2SrWO6:Mn4+, La3+ (BSW:Mn4+, La3+) far-red phosphor was obtained by an addition strategy of La ion to negligible-luminescence BSW:Mn. Deep-red emission peaks at ∼ 664, 679 and 690 nm were observed for BSW:Mn4+, La3+ with the excitation band in the 250 ∼ 600 nm spectral range, which are well matched to the absorption of chlorophyll and phytochromes. An impressive nanorod surface micro-morphology was observed in BSW samples and the size of the surface-grown nanorods can be changed by the addition of La ions. It was speculated that the generation of oxygen vacancies in BSW:Mn probably causes the self-reduction process of Mn4+ → Mn2+, and a charge replenishment mechanism was proposed to explain the abnormal luminescence of Mn4+ ions. The BSW:0.5%Mn, 5%La phosphor showed a CIE chromaticity coordinate of (0.724, 0.276) with a high color purity of 100%. In addition, the internal and external quantum efficiency of BSW:0.5%Mn, 5%La phosphor reach as high as 51.9% and 39.5%, respectively. Finally, LED devices were fabricated by using the as-prepared BSW:0.5%Mn, 5%La phosphor and applied in the illumination on tomato seeds. It shows that the LED devices can promote the seeding of tomatoes effectively, indicating a potential application value in the plant cultivation field.