Structural regulation and properties of Ca8.96LixNa1-xAl0.667(PO4)7:0.04Eu2+full spectrum phosphor

A series of Ca 8.96 Li x Na 1- x Al 0.667 (PO 4 ) 7 : 0.04Eu2+ white-light phosphors with full spectral emission properties were prepared using Site occupation engineering and solid-phase reaction. The crystal structure and photoluminescence properties were analyzed comprehensively. Ca 8.96 Li x Na 1- x Al 0.667 (PO 4 ) 7 : 0.04Eu2+ phosphors exhibit broad, highly intense absorption bands in the scope of 300-440 nm, demonstrating that commercial UV LED chips could efficiently excite them. Excited at 365 nm, Ca8.96NaAl0.667(PO4)7: 0.04Eu2+ undoped with Li+ ions showed a broad and powerful cool white light-emitting band. As the doping of Li+, on one hand, Eu2+ optionally occupies Ca1, Ca2/Ca3 and Na sites, and influenced by centroid shift and crystal field effect, the fitting emission peaks corresponding to each site show different degrees of red shift or blue shift. The fitted emission peaks for each site exhibit varying degrees of red shift or blue shift. In contrast, the variations in the intensities of the three sets of Gaussian peaks generated from the fit confirm the movement of Eu2+ ions from the Ca1 site to the Na/Li site. Finally, Ca 8.96 Li 0.2 Na 0.8 Al 0.667 (PO 4 ) 7 : 0.04Eu2+ phosphor was chosen for coating on a 365 nm LED chip, yielding a high-quality WLED device with CCT and Ra of 6202 K and 89.6, respectively. A higher color rendering index indicates that Ca 8.96 Li x Na 1- x Al 0.667 (PO 4 ) 7 : 0.04Eu2+ phosphors could be used in solid-state lighting with a full visible spectrum.