“…Although numerous LLP materials have been previously reported, it was only in 1996 that this field of research began to attract much wider interest due to the discovery of the highly bright LLP of SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphor by Matsuzawa et al 9 Currently, LLP materials are extensively applied in emergency lighting, safety signage, 10 optical storage media, 11,12 in vivo imaging, 1,13 drug carriers, 14 solar energy, 15 and even photocatalysis. 16,17 At present, the best performances of LLP materials are still exhibited by Eu 2+ -doped alkali-earth aluminate phosphors such as SrAl 2 O 4 :Eu 2+ ,Dy 3+ (green, >30 h) 9 and CaAl 2 O 4 :Eu 2+ ,Nd 3+ (blue, >10 h). 18 During the past decades, a large number of new LLP phosphors have been developed.…”