Luminescence of emission-tunable Na15.6Ca3.84Si12O36:Ce3+,Tb3+,Na+ phosphors for near-ultraviolet light-emitting diodes

A series of Na15.6Ca3.84Si12O36:Ce3+,Tb3+,Na+ (NCS:Ce3+,Tb3+,Na+) phosphors were prepared by conventional solid-state reaction method, and their photoluminescence properties under near-ultraviolet (NUV) excitation were studied. The excitation spectrum of Ce3+-single-doped NCS showed a broad excitation band from 250 to 400 nm, which could well match with the emission wavelength of the NUV LED chip. Upon 365 nm excitation, the NCS:Ce3+,Na+ phosphor demonstrated a blue emission in the range of 400–600 nm with the predominated peak at 443 nm. By co-doping Tb3+ into NCS:0.04Ce3+,0.04Na+, tunable-emission was realized due to the energy transfer from Ce3+ to Tb3+, and nearly white light was also obtained. The investigation also revealed that warm white light could be further generated by combining the NCS:0.04Ce3+,yTb3+,(0.04+y)Na+ with other red-emitting phosphors. Thus, the NCS:Ce3+,Tb3+,Na+ phosphors could be promising candidate for white LEDs.

CIE chromaticity diagram for NCS:0.04Ce3+,yTb3+, (0.04+ y)Na+ (Points 1–5 are for y=0, 0.015, 0.03, 0.045, 0.06, and 0.075, respectively) (Insets (a, b) show the digital photographs of the typical NCS:0.04Ce3+,0.04Na+ and NCS:0.04Ce3+,yTb3+,(0.04+y)Na+ under 365 nm ultraviolet lamp irradiation)Figure optionsDownload as PowerPoint slide