Luminescence properties of NaCaGaSi2O7:RE, Li+ (RE = Ce3+, Eu3+ or Tb3+) phosphors for UV excitable white light emitting diodes

• The new phosphor applied in UV-LEDs was successfully synthesized by solid-state reaction.
• Using Li2CO3 as charge compensation enhances the luminescence intensity.
• Their structure, thermal and luminescent properties are researched.
• The CIE coordinates presenting very well with doping Ce3+ (blue), Eu3+ (red) or Tb3+ (green).

Novel silicate-based phosphors—NaCaGaSi2O7:RE, Li+ (RE = Ce3+, Eu3+ or Tb3+) was synthesized by a solid state reaction. The crystal structure, luminescence properties, as well as concentration quenching, thermal stability and CIE chromaticity coordinates were investigated. By introducing Ce3+, Eu3+ and Tb3+ into NaCaGaSi2O7, an intense blue emission at 388 nm, red emission at 613 nm and green emission at 541 nm could be generated in optimal excitation wavelengths of 332 nm, 393 nm and 377 nm, respectively. The optimized doping concentration and critical energy transfer distance of Ce3+, Eu3+ and Tb3+ in NaCaGaSi2O7 were determined to be 1, 10, 25 mol% and 30.61, 10.47 and 14.21 Å, respectively. The CIE coordinates of NaCaGaSi2O7: 1% Ce3+, 1% Li+, NaCaGaSi2O7: 10% Eu3+, 10% Li+ and NaCaGaSi2O7: 25% Tb3+, 25% Li+ phosphors were (0.1602, 0.0192), (0.6470, 0.3493) and (0.3211, 0.4820), respectively. The results indicate that the as-synthesized NaCaGaSi2O7:RE, Li+ phosphors were potential candidates for UV-LEDs.

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