“…[10][11][12] Moreover, the excitation bands of Cr 3+ ions are usually located at the blue and red spectral regions, and match well with the emissions of low-cost commercial diode chips. Hence, numerous studies on Cr 3+ -activated phosphors have been reported for NIR pc-LED applications, such as Cr 3+ -doped garnets (X 3 M 2 A 3 O 12 , X = La, Lu, Y, Gd; M = Zr, Hf, Ga; A = Al, Si, Ge), [13][14][15] gallogermanates (La 3 Ga 5 GeO 14 , LaMgGa 11 O 19 ), 16,17 borates [ScBO 3 , GdAl 3 (BO 3 ) 4 ], 18,19 fluorides (Na 3 ScF 6 , Na 3 Al 2 Li 3 F 12 ), [20][21][22] etc. However, NIR phosphors that fulfil all commercial standards, including strong absorption of excitation light, high emission efficiency, and excellent chemical and PL thermal stability, are still very limited.…”