Eu3+-activated NaBa4B3O9 phosphors toward multifunctional LED applications

Currently, most trivalent europium ion (Eu3+)-activated phosphors exhibit dominant red emissions at around 616 nm originating from 5D0 -+ 7F2 transition. However, recently, some works have indicated that Eu3+ ions could generate intense far -red emission (-706 nm), which is assigned to the transition 5D0 -+ 7F4. Thus, utilization of the far -red emission from the transition 5D0 -+ 7F4 could expand the application fields of Eu3+-activated phosphors. Herein, we prepare a series of NaBa4-xB3O9:xEu3+ (x = 0.01, 0.05, 0.1, 0.15, and 0.2 mol) phosphors via the conventional solid-state reaction method. These phosphors possess dual intense emission at around 617 nm (5D0 -+ 7F2) and 706 nm (5D0 -+ 7F4) owing to Eu3+ ions occupying the distorted [BaO8] sites with C2 symmetry. Furthermore, owing to the dual emission, the NaBa4B3O9:Eu3+ phosphors could be used in various applications such as plant growth lighting or phosphor -converted white light emitting diodes.