The chemical deposition method was used to synthesize light-accumulating HfO2–ZrO2 oxide systems with afterglow duration up to 10 min and their spectral-luminescent properties were studied. The HfO2:ZrO2 ratio was found to have a significant effect on the intensity and decay kinetics of the visible luminescence of such systems as well as on the weighting coefficients and positions of individual components of the luminescence and luminescence excitation spectra. The results were explained by the contribution of complex titanium impurity optical centers in ZrO2 to the intracenter luminescence of oxygen vacancies in HfO2 and the competitive quenching of the luminescence by nonradiative recombination sites;

A series of (Gd, Y, Yb, Tb, Ce)3Al2Ga3O12 compositionally disordered compounds with a garnet structure were prepared in the form of ceramics by sintering in oxygen at 1650 °C for 2 h and studied for the luminescent properties and interaction of ions entering the matrix host. The luminescence features of Ce3+ ions were found to be strongly dependent on the Yb concentration. Photoluminescence and scintillation kinetics are characterized by subnanosecond kinetics when the Yb index in the compound exceeds X = 0.3. It opens an opportunity to create an extremely fast and dense scintillation material emitting in a visible range. A further decrease in the Yb index in the compound leads to an increase in the intensity of Yb3+ infrared (IR) emission, whereas Ce3+ and Tb3+ ions contribute to the luminosity of the material by overlapping intra- and intereconfiguration luminescence bands in the spectral range of 300–700 nm. This finding opens an opportunity to create converter materials tolerant to the corpuscular radiation of isotope sources, providing a high efficiency of electric current production when coupled with a silicon photovoltaic element. The compounds were engineered at the nanoscale level, providing control over electronic excitation transfer between luminescent ions.

The luminescence of Er3+ ions in silica glasses synthesized by the direct sol–gel–glass transition method and by melting of activated gel grit using various precursors of optical centers was studied. The formation of complex centers including erbium, aluminum, and alkali metal ions was found to be one way of essentially increasing the half-width of the 4I13/2 → 4I15/2 luminescence band of these ions.

Fused yttrium-alumoborate glasses doped with ytterbium, silicon, chromium, and sodium were synthesized. The influence of the matrix on the “spectroscopic behavior” of chromium ions and the efficiency of their sensitization of Yb 3+ luminescence was established by spectral-luminescence and EPR studies. It was found that (1) chromium in alkali-free glasses is mainly in the oxidation degree Cr(III) with an appreciable admixture of Cr(IV) and Cr(V), (2) the partial replacement of Al 2 O 3 or B 2 O 3 by SiO 2 and Y 2 O 3 by Yb 2 O 3 affects to a different extent the relative concentration of optical centers of chromium ions, (3) the addition of alkali results in the formation of Cr(VI) centers as a result of oxidation of less charged chromium ions and predominantly tetracoordinated Cr 4+ and Cr 5+ , (4) Cr 3+ ions make the main contribution to the luminescence sensitization of Yb 3+ ions, while Cr 4+ ions and to a lesser extent Cr 5+ play the role of luminescence quencher and internal filter. Sensitization of Yb 3+ luminescence through the charge transfer band in Cr(VI) was found. An alkaline glass doped with Cr and Yb upon excitation through the sensitizer produced a luminescence quantum yield of 32% and the conditions for its enhancement were considered. It is shown that the temperature quenching of luminescence of Cr–Yb-containing glasses is significantly lower than that of Cr-containing glasses.

Two series of (Gd, Y, Yb)3Al2Ga3O12 quintuple compounds with a garnet structure and solely doped with Ce and Tb were prepared in the form of ceramics by sintering in oxygen at 1600 °C for two hours and studied for the interaction of activator ions with ytterbium ions entering the matrix. It was shown that the photoluminescence and scintillation of Ce3+ ions are completely suppressed, predominantly by tunneling ionization through the charge transfer state (CTS) of the Ce4+-Yb2+ ions. The photoluminescence of Tb3+ ions is quenched in the presence of ytterbium, but not completely due to the poor resonance conditions of Tb3+ intraconfiguration transitions and the CTS of the single Yb3+ and the CTS of Ce4+-Yb2+ ions. The scintillation in the visible range of both Ce3+- and Tb3+-doped samples is intensely quenched as well, which indicates strong competition from Yb3+ ions to activators in interaction with the Gd substrate.

Fused yttrium-alumoborate glasses doped with ytterbium, silicon, chromium, and sodium were synthesized. The influence of the matrix on the “spectroscopic behavior” of chromium ions and the efficiency of their sensitization of Yb3+ luminescence was established by spectral-luminescence and EPR studies. It was found that (1) chromium in alkali-free glasses is mainly in the oxidation degree Cr(III) with an appreciable admixture of Cr(IV) and Cr(V), (2) the partial replacement of Al2O3 or B2O3 by SiO2 and Y2O3 by Yb2O3 affects to a different extent the relative concentration of optical centers of chromium ions, (3) the addition of alkali results in the formation of Cr(VI) centers as a result of oxidation of less charged chromium ions and predominantly tetracoordinated Cr4+ and Cr5+, (4) Cr3+ ions make the main contribution to the luminescence sensitization of Yb3+ ions, while Cr4+ ions and to a lesser extent Cr5+ play the role of luminescence quencher and internal filter. Sensitization of Yb3+ luminescence through the charge transfer band in Cr(VI) was found. An alkaline glass doped with Cr and Yb upon excitation through the sensitizer produced a luminescence quantum yield of 32

Fused yttrium-alumoborate glasses doped with ytterbium, silicon, chromium, and sodium were synthesized. The influence of the matrix on the "spectroscopic behavior" of chromium ions and the efficiency of their sensitization of Yb3+ luminescence was established by spectral-luminescence and EPR-studies. It was found that (1) chromium in alkali-free glasses is mainly in the oxidation degree Cr(III) with an appreciable admixture of Cr(IV) and Cr(V), (2) the partial replacement of Al2O3 or B2O3 by SiO2 and Y2O3 by Yb2O3 affects to a different extent the relative concentration of optical centers of chromium ions, (3) the addition of alkali results in the formation of Cr(VI) centers as a result of oxidation of less charged chromium ions and predominantly tetracoordinated Cr4+ and Cr5+, (4) Cr3+ ions make the main contribution to the luminescence sensitization of Yb3+ ions, while Cr4+ ions and to a lesser extent Cr5+ play the role of luminescence quencher and internal filter. Sensitization of Yb3+ luminescence through the charge transfer band in Cr(VI) was found. An alkaline glass doped with Cr and Yb upon excitation through the sensitizer produced a luminescence quantum yield of 32% and the conditions for its enhancement were considered. It is shown that the temperature quenching of luminescence of CrYb-containing glasses is significantly lower than that of Cr-containing glasses.

Fused yttrium-alumoborate glasses doped with ytterbium, silicon, chromium, and sodium were synthesized. The influence of the matrix on the "spectroscopic behavior" of chromium ions and the efficiency of their sensitization of Yb3+ luminescence was established by spectral-luminescence and EPR-studies. It was found that (1) chromium in alkali-free glasses is mainly in the oxidation degree Cr(III) with an appreciable admixture of Cr(IV) and Cr(V), (2) the partial replacement of Al2O3 or B2O3 by SiO2 and Y2O3 by Yb2O3 affects to a different extent the relative concentration of optical centers of chromium ions, (3) the addition of alkali results in the formation of Cr(VI) centers as a result of oxidation of less charged chromium ions and predominantly tetracoordinated Cr4+ and Cr5+, (4) Cr3+ ions make the main contribution to the luminescence sensitization of Yb3+ ions, while Cr4+ ions and to a lesser extent Cr5+ play the role of luminescence quencher and internal filter. Sensitization of Yb3+ luminescence through the charge transfer band in Cr(VI) was found. An alkaline glass doped with Cr and Yb upon excitation through the sensitizer produced a luminescence quantum yield of 32% and the conditions for its enhancement were considered. It is shown that the temperature quenching of luminescence of CrYb-containing glasses is significantly lower than that of Cr-containing glasses.

The glass‐ceramics (GC) of gadolinium aluminum gallium garnets with the expected composition of Gd 3 Al 3 Ga 2 O 12 :Ce and Gd 3 Al 3 Ga 2 O 12 :Ce,Be (GAGG:Ce and GAGG:Ce,Be, respectively) are fabricated by crystallization from the Gd 2 O 3 –Al 2 O 3 –Ga 2 O 3 –CeO 2 –SiO 2 –BeO (Gd:Ga:Al ratio is close to 3:2:3) glasses. The influence of Be 2+ co‐doping (including doping level) on the luminescent properties of the GAGG is demonstrated. In particular, Be co‐doping results in the suppression of the Ce 3+ ‐related radioluminescence (RL) and as a consequence, the light yield is lowered as well. The conclusion is made that Be 2+ creates effective electron or hole trapping centers.

Transparent germanosilicate glass-ceramics embedding γ-Ga2O3:Ni2+ nanocrystals have been fabricated. Optical amplification in the glass-ceramics was observed at ∼1.32μm under 0.96μm diode laser pumping in the 3A2g (3F) ↔ 3T2g (3F) resonance band of Ni2+ ions. The magnitude of the gain was estimated to be ∼13%.

Measurements of the relative fluorescence intensity and the lifetime of the excited states of the Ce 3+ ions in an aqueous solution of cerium nitrate at various graphene oxide concentrations have shown that under the optical excitation of Ce 3+ static quenching of fluorescence by graphene oxide takes place. The Stern-Volmer association constant of aquacomplex cerium with graphene oxide is measured to be 24.7 L/g. This value is much lower than the constants for cationic dyes of rhodamines and metal cations and is explained by the presence of negative charges on the interacting particles.

We study the silica gel-glasses obtained by vitrification in air or in a gas mixture of H 2 :Ar xerogels doped with Sm, Al, and Ba. It is found that during their synthesis it is possible to form impurity hexagonal and tetragonal crystallites of SiO 2 and tetragonal crystallites of SmSi 2 . When the reducing synthesis conditions are applied, the incorporation of samarium in glass simultaneously in two oxidation states (3+ and 2+) takes place. Meanwhile, Sm-Al-containing glasses provide a sufficiently effective sensitization of the luminescence of Sm 2+ ions by Sm 3+ ions, while in Sm-Al-Ва-containing glasses this effect is absent because Sm 2+ ions are localized mainly in the glass sublattice formed with the participation of Ba 2+ ions. Based on the spectra obtained, the positions of the energy states of the Sm 2+ and Sm 3+ ions in such glasses are calculated.

The fifth author's name should read K. N. Nishchev. Figure 3 on page 587 is incorrect.

Static fluorescence quenching by graphene oxide at various concentrations was observed by measuring the relative fluorescence intensity and excited-state lifetime of optically excited Ce 3+ ions in aqueous cerium nitrate solutions. The measured Stern–Volmer association constant of Ce aqua complexes with graphene oxide was 24.7 L/g, which was significantly less than the constants for cationic rhodamine dyes and metal cations and was explained by the negative charges on the interacting species.

Glasses of the TeO2-WO3-Yb2O3 system are synthesized for wide range of Yb3+ concentrations of up to 6.0 × 1021 ions/cm3. The spectral-luminescent properties of lightly doped samples are investigated at room temperature and at the boiling point of liquid nitrogen. The energies of the Stark levels of the ground and excited states of Yb3+ ions incorporated into tungsten–tellurite glass are determined by analyzing the low-temperature spectra. The absorption, emission, and gain cross section spectra are obtained. The excess of the measured fluorescence decay time over the radiative lifetime ∼0.3 ms derived from the absorption spectra is attributed to the reabsorption effect in bulk samples. Measurements of lightly doped glass powder in the immersion liquid are made to reduce the effect of reabsorption. The fluorescence decay time of the powder is very close to the calculated radiative lifetime. Compared with phosphate, silicate, and other Yb3+-doped glasses, the tungsten–tellurite glass has a promising potential as a gain medium for lasers and amplifiers.

Crystalline phosphors made of yttrium aluminum borates YAl3(BO3)4 doped with cerium have been synthesized by colloidal chemical approach involving co-precipitation of precursors from aqueous solutions of the corresponding salts in the presence of boric acid that is followed by heat treatment. Structural phase transitions occurring during the synthesis of YAl3(BO3)4:Ce3+ were studied using thermal analysis methods (TG, DTA, and DSC). The crystalline structure and luminescent properties of the synthesized compounds were investigated by the means of X-ray powder diffraction and optical spectroscopy. The decrease in the luminescence intensity and increased splitting of the main term of Ce3+ ions of YAl3(BO3)4:Ce3+ were observed at a higher concentration of the ion-activator of 10 % wt. This observation was attributed to the alteration of the structure of optical centers due to the partial oxidation of Ce3+ ions into the Ce4+ state.

Peculiarities in the crystal structure and spectral-luminescent properties of compound oxide systems Y3Al5O12:Ce3+/Lu2O3 and Lu3Al5O12:Ce3+/Lu2O3 are studied using the neutron diffraction and optical spectroscopy methods. The influence of the introduced oxide on the structural and luminescent properties of those systems is shown to have a complicated character depending not only on the formation of a stable defect garnet structure and the diffusion of Ce3+ ions from the matrix into the oxide, but also on the interaction between the oxide and the matrix, which gives rise to the formation of new phases.

Yttrium-alumina-borate glasses activated by the Yb3+ ions with compositions close to the huntite-like (Y1−xLnx)Al3(BO3)4 crystals have been synthesized by conventional melt-quenching technique in a platinum crucible, and their spectral-luminescent and laser properties have been investigated. It is established that this activator forms in the given glass one type of optical centers having the radiation decay time of 870 ± 40 μs. The limiting quantum yield of its luminescence in the case of complete dehydration of the glass will amount to ≈94%. The main laser parameters have been calculated and the nonlinearity of the refractive index and the threshold of laser-induced destruction of the glass surface have been determined. The lasing has been obtained on the glass plate of 2.1 mm thickness with a threshold of ≈60 W/mm2 estimated by specific absorbed power.

It is shown that gold nanoclusters and nanoparticles, possessing luminescence and plasmon properties depending on size, can form in potassium-aluminum-phosphate glass as a result of heat-treatment at temperatures below T (g) .