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Copper‐doped corundum (α‐Al2O3) possesses an intense broadband photoluminescence in the near infrared. This photoluminescence is originated from Cu2+ ions, which substitute for Al3+ ions in corundum lattice. Co‐doping with Ge is necessary to obtain the luminescent material. It seems, that simultaneous introduction of Ge is needed to provide the charge compensation for heterovalent Cu2+ → Al3+ substitution, in such a way that the whole process (Cu2+, Ge4+) → 2Al3+ is charge‐balanced. The broad photoluminescence spectrum matches well with transparency window of silica optical fibers and the quantum yield seems to be satisfactory, so copper‐doped corundum can become demanded as a new active media for solid state lasers and amplifiers. This is the first example of photoluminescence from octahedrally coordinated Cu2+ ion in oxide materials. [ABSTRACT FROM AUTHOR]

Single crystal of TlCl was doped with NIR photoluminescent univalent bismuth cations by prolonged immersion in liquid bismuth metal. The ion exchange Tl+ + Bi0 ↔ Tl0 + Bi+ at the crystal surface with subsequent Bi+ migration to the bulk are expected to drive the doping process. Contrary with Bi‐doped TlCl crystals, grown by Bridgman method, the ion exchange does not produce the additional nonluminescent bismuth‐containing centers. The investigation of photoluminescence emission and excitation spectra lead to the conclusion, that Bi+ is the main NIR emissive center in Bi‐doped TlCl. Near‐IR photoluminescent univalent bismuth cations can be introduced into TlCl crystal by ion exchange route. [ABSTRACT FROM AUTHOR]

VO x/SiO2-Al2O3 catalysts were prepared by grafting vanadyl acetylacetonate onto the supports with a SiO2 content between 0 and 100 wt. %. The degree of polymerization of VO x species and acidity both of pristine supports and the catalysts were evaluated. To determine their on-stream stability and carbon deposition activity in nonoxidative propane dehydrogenation, continuous-flow tests and in situ thermogravimetric measurements were performed. The rate constants of catalyst deactivation and carbon deposition were derived from kinetic evaluation of these experiments. Gathered experimental evidence pointed out that VO x species were significantly more active for coke formation than acid sites of the supports. The rate constant of carbon formation was found to increase with the degree of polymerization of VO x species, whereas no correlation between catalyst acidity and the rate constants of coking or deactivation could be drawn. [ABSTRACT FROM AUTHOR]

Copper‐doped corundum (α‐Al2O3) possesses an intense broadband photoluminescence in the near infrared. This photoluminescence is originated from Cu2+ ions, which substitute for Al3+ ions in corundum lattice. Co‐doping with Ge is necessary to obtain the luminescent material. It seems, that simultaneous introduction of Ge is needed to provide the charge compensation for heterovalent Cu2+ → Al3+ substitution, in such a way that the whole process (Cu2+, Ge4+) → 2Al3+ is charge‐balanced. The broad photoluminescence spectrum matches well with transparency window of silica optical fibers and the quantum yield seems to be satisfactory, so copper‐doped corundum can become demanded as a new active media for solid state lasers and amplifiers. This is the first example of photoluminescence from octahedrally coordinated Cu2+ ion in oxide materials. [ABSTRACT FROM AUTHOR]

Abstract: Bi+-doped single crystals of triple chloride CsCdCl3 were prepared by the Bridgman method. Bismuth monocation is responsible for characteristic two-peaked absorption feature in visible and long lived NIR luminescence in this crystal. The splitting of the Bi+ lowest electronic states by crystal field is considered. The absorption spectrum is assigned to optical transitions of A→E type in two nonequivalent Bi+ positions of D3h and C3v symmetry. The possibility of Jahn–Teller effect in Bi+ excited states of E type is discussed in relation with absorption and luminescence excitation spectra properties. [Copyright &y& Elsevier]

Abstract: Monocation Bi+ isomorphically substitutes potassium in KAlCl4 and KMgCl3 chlorides. Having the unique 6p2 open-shell electronic configuration, Bi+ possesses a number of low-lying excited states, and displays broadband long-lived NIR photoluminescence in ternary chloride crystals. [Copyright &y& Elsevier]

Abstract: Creation of bismuth-containing near-infrared (NIR) luminescent centers by synproportionation reaction of Bi3+ and Bi0 was demonstrated in borate and phosphate glasses. This finding is discussed in the light of low-valence nature of bismuth NIR-luminescent centers. The experimental data is consistent with the hypothesis of univalent Bi+ (and, possible, subvalent cluster Bi ions) as a source of NIR luminescence. The dependence of Bi luminescent centers stability on oxoacidity of glass melts was discussed. [ABSTRACT FROM AUTHOR]

Broadband NIR photoluminescence (from 1000 to 2500 nm) was observed from partially reduced AlCl₃/ZnCl₂/BiCl₃ glass, containing subvalent bismuth species. The luminescence consists of three bands, assigned to Bi⁺ , Bi₂⁴⁺, and Bi₅³⁺ ions. The physical and optical characteristics of these centers and possible contribution to NIR luminescence from bismuth-doped oxide glasses are discussed.