“…It consists of lines in the orange and red spectral region exhibiting the characteristic f-f transitions of Eu 3+ . They are 5 D 1 → 7 F 1 (541 nm), 5 D 1 → 7 F 2 (557 nm), 5 D 0 → 7 F 0 (582 nm), 5 D 0 → 7 F 1 (590 and 598 nm), 5 D 0 → 7 F 2 (615 and 627 nm) and 5 D 0 → 7 F 3 (654 nm) respectively [22][23][24]. It can be seen from this figure that the spectra is dominated by the prominent band at 627 nm due to the 5 D 0 → 7 F 2 transition.…”