A broadband-excited and narrow-line GdBO3: Ce3+, Tb3+, Eu3+ red phosphor with efficient Ce3+ → (Tb3+)n → Eu3+ energy transfer for NUV LEDs

• GdBO3: Ce3+, Tb3+, Eu3+ phosphors show blue–green–red emission under NUV excitation.
• Energy transfer take place through Ce3+ → (Tb3+)n → Eu3+ scheme.
• They can be used in applications for near-UV light-emitting-diodes.

A broadband-excited and narrow-line red phosphor, GdBO3: Ce3+, Tb3+, Eu3+, was synthesized by solid state method. The photoluminescence excitation and emission spectra, concentration effect and decay curves are investigated. The emission color of the phosphors can be tuned from blue (0.168, 0.018) to green (0.291, 0.590) and eventually to red (0.612, 0.372) through efficient Ce3+ → (Tb3+)n → Eu3+ energy transfer. The optimal-composition phosphor, GdBO3: 0.01Ce3+, 0.50Tb3+, 0.01Eu3+, gives an intense Eu3+ red 4f–4f sharp emission with a strong 4f–5d absorption band of Ce3+ at 356 nm, which perfectly matches with the dominant emission band of NUV LEDs, and makes it as a potential red phosphor for NUV LEDs.