Red luminescence with controlled rise time in La2MgTiO6: Eu3+

La2MgTiO6 (LMT) doped with Eu3+ ions has been prepared for the first time by the co-precipitation method. All samples crystallize in the same orthorhombic crystal structure and the unit cell volume decreases with increasing dopant concentration. The Eu3+ luminescence can be excited either into O2- -> Eu3+ Charge Transfer State (CTS) with a maximum at 320 nm or into 4f levels and exhibits the emission spectrum characteristic for Eu3+ ions at the low symmetry site. TiO6 groups are also optically active with absorption at 305 nm and a weak broadband emission at 478 nm. The configurational coordinate diagram was constructed based on the absorption, emission and thermal quenching energy values. The relative thermal sensitivity of the intensity ratio between luminescence excited at 532 nm and 266 nm is above 1% for temperatures below 230 K and 3% for 77 K. The rise time of the D-5(0) luminescence after the pulse excitation of the D-5(1), resulting from both the multiphonon relaxation and the cross-relaxation, strongly depends on the Eu3+ concentration and goes from 94.1 mu s for 0.1% Eu3+ down to 39.6 mu s for 7% Eu3+. It is only observed when the sample is excited at 532 nm (into the D-5(1) level). When the sample is excited into the CTS, the rise time is not observed. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

La2MgTiO6 (LMT) doped with Eu3+ ions was successfully prepared for the first time using the co-precipitation method. The luminescence of Eu3+ is sensitive to excitation modes and temperatures, showing strong thermal sensitivity. The TiO6 groups also contribute to the optical activity of the material, playing an important role in its luminescent properties.