Wickleder, Claudia
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Publication Access status: Metadata only , Luminescence Properties of M(AlCl4)2:Yb2+ (M = Ca, Sr, Ba): Ideal Materials for the Investigation of Structure–Luminescence RelationshipsIn this work, the chloride system M(AlCl4)2 (M = Ca, Sr, Ba) doped with Yb2+ is investigated in greater detail. The influence of the [AlCl4]− ion on the position of the emission band of Yb2+ is investigated and the emission spectra are recorded. The emission spectra of the Yb2+-doped materials are characterized by broad 4f135d1 (HS) ↔ 4f14 transitions with maxima in the range between 416 nm (Ca) and 421 nm (Ba) (24,061–23,738 cm−1), whereas the Ba compound features an additional 4f135d1 (LS) ↔ 4f14 emission band at 397 nm (25,203 cm−1) at lower temperatures. The unusual reverse order of the positions of the emission maxima (Ba < Sr < Ca) most probably indicates an influence of the local symmetry on the location of the emission bands. Temperature-dependent emission and decay time measurements reveal strong thermal quenching processes, which gives additional insight into the mechanistic properties of the luminescence. An investigation of the decay times for all transitions reveals generally shorter values compared to values found in the literature, which was likely caused by the strong thermal quenching.Source Type:Article4 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Luminescence Properties of Y3F[Si3O10]:Ln3+ (Ln = Eu, Tb, Er) with Thalenite-Type Host Lattice and Crystal Structure of Tm3F[Si3O10]With Tm3F[Si3O10], a new representative of the Ln3F[Si3O10] series could be synthesized by the reaction of Tm2O3, TmF3 and SiO2 (molar ratio: 1:1:3), applying an excess of CsBr as a fluxing agent in gas-tightly sealed platinum crucibles for eight days at 750 °C, and designed to yield Tm3F3[Si3O9] or Cs2TmF[Si4O10]. Single crystals of Tm3F[Si3O10] (monoclinic, P21/n; a = 725.04(6), b = 1102.43(9), c = 1032.57(8) pm, β = 97.185(7)°; Z = 4) appear as pale celadon, transparent, air- and water-resistant rhombic plates. According to its thalenite-type structure, Tm3F[Si3O10] contains catena-trisilicate anions [Si3O10]8− and triangular [FTm3]8+ cations. The three crystallographically different Tm3+ cations are coordinated by seven plus one (Tm1) or only seven anions (Tm2 and Tm3) exhibiting a single F− anion for each polyhedron, additional to the majority of O2− anions. Furthermore, the luminescence properties of the isotypic colorless compound Y3F[Si3O10] doped with Eu3+ (red emission), Tb3+ (green emission) and Er3+ (yellow and infrared emission), respectively, are reported in presenting their different excitation and emission spectra.Source Type:Article1
