Broadened near-ultraviolet absorption and enhanced luminescence intensities of Ca6La2−xEuxNa2(PO4)6F2 by co-doping Sm3+ for light emitting diodes

Eu3+ and Sm3+ activated fluoro-apatite Ca6La2Na2(PO4)6F2 with chemical formulas Ca6La2−xLnxNa2(PO4)6F2 (Ln = Eu3+, Sm3+) were prepared by a solid state reaction technique at high temperature. The photoluminescence results show that Ca6La2−xEuxNa2(PO4)6F2 and Ca6La2−xSmxNa2(PO4)6F2 can be excited by near-ultraviolet light efficiently, then exhibit dominative emissions at ∼617 and 593 nm, respectively. To broaden the absorption at near-ultraviolet wavelength range and enhance Eu3+ emission intensity under 400 nm excitation, Sm3+ ions are induced in the system, and the photoluminescence properties of Eu3+/Sm3+ co-doped samples Ca6La1.50−xSmxEu0.50Na2(PO4)6F2 are investigated.

► CLPF:xEu3+ and CLPF:xSm3+ were prepared by using a solid-state reaction technique.
► CLPF:xEu3+ and CLPF:xSm3+ exhibit intense absorption in n-UV region around 400 nm.
► The introduction of Sm3+ ions can broaden the absorption bands in 395–405 nm.