Blue up-conversion emission from U4+-ion doped into Cs2ZrCl6 single crystal under green light (19436 cm−1) excitation Original Research Article

For the first time blue up-conversion emission from U4+ (5f2)-ion doped into a Cs2ZrCl6 single crystal under green light (19436 cm−1) excitation has been observed and characterized. Five, blue emission bands, centered at 19780, 20010, and 20280 cm−1 for the 1I6→3H4 U4+-transitions and at 20700 and 20970 cm−1 for the 3P2→3H4 U4+-transitions, have been observed. This up-conversion process involves a two-photon absorption. Fluorescence efficiencies of 8.78 × 10−4 and 4.20 × 10−5 have been estimated for the 1I6→3H4 (19780, 20010 and 20280 cm−1) and the 3P2→3H4 (20700 and 20970 cm−1) emissions in U4+-ion, respectively, at room temperature for the sample doped with 1 wt% UCl4. An up-conversion mechanism is proposed.