Photoluminescent properties of NaCl:Ce3+ phosphor synthesized using antisolvent crystallization

A Ce3+-doped NaCl phosphor was synthesized using the antisolvent crystallization with ethanol as the antisolvent. The structural and optical properties of the synthesized NaCl:Ce3+ phosphor were investigated by X-ray diffraction (XRD) analysis, photoluminescence (PL) analysis, PL excitation spectroscopy, and luminescence decay time measurement. The XRD data indicated that the NaCl host lattice can be expanded when Ce atoms are incorporated. The emission and excitation energies of the Ce3+ 4f↔5d transitions in the NaCl:Ce3+ host were strongly influenced by the Ce doping concentration. The Ce3+-related 5d→4f (2F5/2, 2F7/2) blue emissions showed red-shift with increasing doped Ce concentration. While the high-energy excitation peak [4f→5d (2T2)] at ~4.6 eV (~270 nm) did not show any spectral shift, the low-energy excitation peak [4f→5d (2E)] showed clear blue-shift with increasing doped Ce concentration (~3.9–4.1 eV). Energy level scheme for the Ce3+ ion in the NaCl host was proposed with the aid of the configurational-coordinate model. The luminescence decay time was also found to show the emitted light wavelength dependence given by τeff=0.25λ−77.3 ns with λ=320–440 nm.