Multi-color emission from lanthanide ions doped into niobium oxide

Nanostructure and Luminescent Properties of Bimetallic Lanthanide Eu/Gd, Tb/Gd and Eu/Tb Coordination Polymers

“…Furthermore, as the band corresponding to the hypersensitive transition 5 D 0 → 7 F 2 is more intense than the band due to the magnetic dipole transition 5 D 0 → 7 F 1 , the Eu 3+ occupies a site without an inversion center [44,46]. For the EuTb-6 and TbGd-5 samples, bands related to the Tb 3+ ion were observed at 492, 543, 585, 620 and 656 nm, and they were ascribed to the 5 D 4 → 7 F J (J = 6, 5, 4, 3 and 2) transitions, respectively [25,40]. Figure 8a presents the emission spectra of the Eu 3+ and Tb 3+ ions of the mixed LnMOF samples.…”

“…When monitored at 543 nm (Figure 7a), the EuTb-6 and TbGd-5 MOF samples presented terbium transitions from the 7 F6 ground to the 5 D1 (325 nm); 5 L7,8, 5 G3 (340 nm); 5 L9, 5 D2, 5 G5 (351 nm); 5 L10 (368 nm); and 5 G6, 5 D3 (376 nm) and 5 D4 (487 nm) [25,40], whereas when monitoring at 617nm (Figure 7b), EuTb-6 and EuGd-4 presented bands attributed to europium transitions from the 7 F1 state to the 5 D1 excited state at 535 nm, and from the 7 F0 ground state to the 5 D1 (524 nm); 5 D2 (464 nm); 5 D3 (417 nm); 5 L6 (392 nm); 5 G2 (383 nm); 5 D4 (361 nm) and 5 H6 (317 nm) [41][42][43][44]. However, for the EuTb-6 MOF sample, even monitoring the Eu3+ ion at 617 nm, Tb 3+ transitions were found from the 7 F6 ground to the 5 D1 (325 nm); 5 L7,8, 5 G3 (340 nm); 5 L9, 5 D2, 5 G5 (351 nm); 5 L10 (368 nm); 5 G6, 5 D3 (376 nm) and 5 D4 (487 nm), consequent from the energy between the Tb 3+ and Eu 3+ ions [25,38].…”