A multicolor emitting single phase phosphor Ba₃LaNa(PO₄)₃F

A series of Ba₃LaNa(PO₄)₃F (BLNPF): Eu²⁺, Pr³⁺ phosphors were synthesized by solid state reactions and their luminescent properties were investigated in detail. Under near-ultraviolet (n-UV) light excitation, the photoluminescence (PL) spectra of the BLNPF: Eu²⁺, Pr³⁺ phosphors consist of a broad blue emission band from Eu²⁺ and a group of red emission peaks as well as near infrared (NIR) emission peaks from Pr³⁺. These emissions not only coincide with the absorption spectra of chlorophyll and carotenoid of plants, but also overlap with the absorption of bacteriochlorophyll. Their intensities could be tuned by adjusting the energy transfer (ET) process from Eu²⁺ to Pr³⁺ to satisfy the absorption requirements for different plants and bacteria. The ET mechanism from Eu²⁺ to Pr³⁺ is demonstrated to be an exchange interaction, on the basis of the PL spectra and decay curves of the phosphors. The results suggest that BLNPF: Eu²⁺, Pr³⁺ with multicolor emission could perfectly act as phosphor candidates for application in plant growth n-UV LED.