High energy transfer efficient and thermally stable red emission via Sm3+-sensitized Eu3+ energy transfer in BaLaInO4 layered perovskite phosphors

Developing chemically stable red-emitting phosphors with strong near-ultraviolet (NUV) absorption is crucial for high-quality phosphor-converted lighting. Herein, a series of Sm3+- and Sm3+/Eu3+-activated BaLaInO4 (BLIO) layered perovskite phosphors were synthesized via a conventional solid-state route. Sm3+-doped BLIO exhibits intense orange-red emission under 409 nm excitation, originating from the 4G5/2 → 6HJ transitions. Upon Eu3+ co-doping, the emission color is continuously tuned from orange to red, accompanied by a pronounced enhancement of the Eu3+ 5D0 → 7F2 transition. Concentration-dependent luminescence analysis and Dexter-Reisfeld fitting reveal that Sm3+ → Eu3+ energy transfer is dominated by a dipole-dipole interaction, enabled by the small energy gap (0.0597 eV) between Sm3+ 4G5/2 and Eu3+ 5D0 levels, yielding a high transfer efficiency of 71.75 %. Temperature-dependent measurements demonstrate superior thermal stability under Sm3+-sensitized excitation. And, the BLIO:Sm3+,Eu3+ phosphor was utilized in warm w-LED applications, indicating a low correlated color temperature and high color rendering index. These results highlight BLIO:Sm3+,Eu3+ as promising red-emitting phosphors for NUV-excited solid-state lighting applications.