An efficient orange–red‐emitting LiNa 3 P 2 O 7 :Sm 3 + pyrophosphate: Structural and optical analysis for solid‐state lighting

A trivalent rare‐earth ion (Sm 3 + )‐doped LiNa 3 P 2 O 7 (LNPO) phosphor was synthesized using a conventional high‐temperature solid‐state reaction route. A predominant orthorhombic phase of LNPO was observed in all X‐ray diffraction patterns. The surface states of the LNPO:Sm phosphor were confirmed by X‐ray photoelectron spectroscopy. Under 401 nm excitation, the Sm‐doped LNPO phosphors showed sharp emission peaks at 563, 600 and 647 nm that are related to the f–f transition of Sm 3 + ions. The optimum concentration of Sm 3 + (9 mol%) produced Commission Internationale de l'Eclairage chromaticity coordinates, color rendering index and correlated color temperature of (0.564, 0.434), 42 and 1843 K, respectively.