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.

No abstract

While the influence of silicate oxide glass composition on its chemical durability is increasingly known, the contribution of structure only is less well understood, yet is crucial for an accurate description of aqueous alteration mechanisms. The effect of structural disorder can be investigated by varying the thermal history of the glass. Furthermore, the structural changes generated by selfirradiation in nuclear glasses can be compared with those induced by fast quenching. In the context of deep geological disposal of vitreous matrices, it is then challenging to address the structural impact on glass durability. Here, a borosilicate glass, the International Simple Glass, was fiberized to obtain a rapidly quenched sample. The quenching rate and fictive temperature were evaluated from in situ Raman and Brillouin spectroscopies. Multinuclear nuclear magnetic resonance was used to obtain insight into the effect of quenching on the pristine and altered glass structure. Higher bond angle distribution and lower mixing of alkalis were observed in the fast quenched glass. Some of AlO 4 groups are then Ca-compensated, while a part of BO 4 is transformed into BO 3 units. The structural modifications increase the hydrolysis of the silicate network occurring in the forward rate regime at 90°C by a factor of 1.4-1.8 depending on the pH value. Residual rate regime is similarly affected, more significantly at the beginning of the experiments conducted in silica saturated solutions. These findings prove that the reactivity of glass remains controlled by its structure under the various alteration regimes.

No abstract

aThe bismuth doped aluminosilicate phases leucite (KAlSi 2 O 6 ), gallium leucite (KGaSi 2 O 6 ) and pollucite (CsAlSi 2 O 6 ) display broadband NIR photoluminescence. The active center, responsible for this luminescence, is the Bi + monocation, which substitutes for the large alkali metal cations. The Al,Si-disorder in the aluminosilicate framework of studied crystal phases results in the heterogeneity of Bi + luminescent center population, which manifests itself in the characteristic dependency of the luminescence spectrum shape on the excitation wavelength. The relation of NIR emission in Bi + -doped leucite and pollucite phases to the luminescent properties of bismuth-doped glasses is also discussed.

No abstract

No abstract

We observed an intensive near-infrared luminescence in Bi-doped KAlCl4 polycrystalline material. Luminescence dependence on the excitation wavelength and temperature of the sample was studied. Our experimental results allow asserting that the luminescence peaked near 1 um belongs solely to Bi+ ion which isomorphically substitutes potassium in the crystal. It was also demonstrated that Bi+ luminescence features strongly depend on the local ion surroundings