Wickleder, Claudia
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Publication Access status: Metadata only , Glowing selenates: novel alkaline earth nanopArticles(2023); Alkaline earth selenate nanopArticles like SrSeO 4 and SrSeO 4 :Eu 3+ could be synthesized for the first time using a micro emulsion method combined with an in situ -sintering step.Source Type:Article - Some of the metrics are blocked by yourconsent settings
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 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Synthesis and Characterization of Iron-Doped TiO2 Nanotubes (Fe/TiNTs) with Photocatalytic ActivityOne of the most significant global challenges for humans is environmental pollution. The technology to control this problem is the utilization of semiconductors as photocatalysts. In the current study, iron-doped titania nanotubes (Fe/TiNTs) with increased photocatalytic effect were synthesized via a modified hydrothermal method. The products were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy (TEM), gas adsorption, electron spin resonance (ESR) and UV–Vis diffuse reflectance spectroscopy (DRS). TEM results indicated that Fe/TiNTs have a tubular and uniform structure with an average outer diameter of 23–48 nm and length of 10–15 µm. ESR and DRS revealed that Fe3+ ions were successfully introduced into the TiNT structure by replacing Ti4+ ions. An enhanced light absorption in the range of 400–600 nm additionally indicated successful doping. The band gap was narrowed as iron wt% was increased. The photocatalytic activity was evaluated by the degradation of methyl orange (MO) in the presence of Fe/TiNTs and TiTNs by monitoring the degradation of MO under UV light irradiation. An acceleration on the hydration of Portland cement was observed in the presence of 2.0 wt% Fe/TiNTs. Fe/TiNTs can be used as a nanomaterial in cement-based building materials to provide self-cleaning properties to the surface of concrete even in indoor environments.Source Type:Article7
