Cooperative processes in Cs2NaYbF6 elpasolite crystals

Stokes and anti‐Stokes luminescence from cubic elpasolite Cs2NaYF6 crystals doped with Er3+and Yb3+ ions

“…6 and it is clearly single-exponential. For a stoichiometric Cs 2 NaYbF 6 crystal, similar measurement yields τ¼5.7 ms, which is close to the previously reported value [6], τ¼5.63 ms. Thus, the anomalously weak concentration quenching is observed for Yb 3 þ :…”

“…Thus, it is difficult to distinguish these effects spectrally. In [6] it has been found that the decay time of blue emission from a Cs 2 NaYbF 6 crystal is 2.73 ms, which is almost exactly half of τ( Р е п о з и т о р и й Б Н Т У…”

“…The fluoride cubic elpasolite Cs 2 NaYF 6 is isostructural with the chloride elpasolite Cs 2 NaYCl 6 , that has been extensively studied as an low phonon energy host for optically active ions of 3d, 4f and 5f elements, for example Er 3 þ [14,15]. In particular, Cs 2 NaYCl 6 crystals doubly doped with Er 3 þ and Yb 3 þ have been studied as the near-IR-to-visible frequency converters [16,17] based on photon upconversion processes [18].…”

“…Accordingly, the MX 6 octahedra are perfectly cubic with O h site symmetry for trivalent metal ions, while the MX 6 octahedra do not share halide ions with each other, i.e. the elpasolite structure is characterized by the isolated MX 6 octahedra. In addition, as all the halide compounds, elpasolites are materials with low-phonon energy.…”

“…Near-IR ( $ 2.7 μm) emission of Er 3 þ ions in Cs 2 NaYF 6 has been also investigated and the lifetime of the 4 I 11/2 excited-state has been detected to be as long as $ 1 ms at room-temperature for highly-doped ( 410 at%) samples [5]. Absorption and emission as well as crystal field analysis for Yb 3 þ ions in Cs 2 NaYbF 6 has been reported [6][7][8]. In…”