Tsiala Saraidarov

Efficiency and photostability of dye-doped solid-state lasers in different hosts

Abstract We survey the preparation procedures of pyrromethene (PM) and rhodamine dyes in silica, silica–zirconia, organically modified silicate (ormosil) and organic polymer matrices. Absorption and luminescence spectra, as well as decay time fluorescence of pyrromethene dyes are given. The solid-state laser samples were tested and their efficiencies and photostabilities at transversal pumping configuration, are given. Pyrromethene 597 had the best laser dye performance with slope efficiency of 43.3% when doped in ormosil glass and high photostability when doped in poly(methyl methacrylate) (PMMA) . Analysis and explanations for the results are given.

Optical and Conductivity Properties of PbS Nanocrystals in Amorphous Zirconia Sol-Gel Films

Lead sulfide (PbS) nanocrystals (NCs), embedded in amorphous zirconia sol-gel film with different PbS mole concentration (5–30%), were grown at temperature, ranging from 200°C to 350°C. The size of PbS NCs was determined by TEM and by blue shift of the absorption edge. The size increased with an increase of the synthesis temperature and PbS mole concentration. The optical and electrical properties of various sizes of PbS NCs in zirconia film are investigated utilizing absorption, photoluminescence (PL) and current-voltage measurement. The PL spectra were Stokes shifted from the corresponding absorption edge by about 0.5 eV. The latter can be associated with recombination process from surface state. The electrical properties were investigated by the deposition of the PbS NCs-zirconia films on ITO/glass substrate, followed by their coverage with gold contact. The current-voltage characteristics depend on the PbS NCs size and exhibits nonlinear nearly symmetric curve, associated with the space-charge limited current or the tunneling of carriers through the nanocrystalline film.

Luminescence intensification of lanthanide complexes by silver nanoparticles incorporated in sol-gel matrix

Abstract We present how the luminescence of europium RR-2-P-oxides complexes can be increased by interaction of electronic levels of the complex with the radiation field of silver nanoparticles (NPs). The procedure by which silver NPs are formed in a sol-gel polyurethane matrix precursor was elaborated. The formed Ag NPs were combined with Eu complex incorporated in ormocer matrix. The emission spectra of the complexes without silver NPs were compared with spectra of the same complexes with addition of silver NPs. As the result of the interaction of the electronic levels of lanthanide ligands with silver plasmons, dramatic increase of luminescence was observed.

Luminescent properties of silica and zirconia xerogels doped with europium(III) salts and europium(III) cryptate incorporating 3,3′-biisoquinoline-2,2′-dioxide

Eu+3 cryptate with 3,3′-biisoquinoline-2,2′-dioxide unit was incorporated into glass films consisting of zirconia dioxide and into hybrid ormosil films. The absorption and the emission intensities of the europium complex were compared to the intensity of the non-complexed europium ion in the films. The transition probabilities of the complex are increased as a result of the mixing of the europium orbitals with the ligand orbitals. The emission is additionally increased as the non-radiative relaxation is diminished by the cage effect.

The luminescence of Bi, Ag and Cu in natural and synthetic barite BaSO4

The time-resolved laser-induced luminescence of natural barite BaSO 4 is compared with synthetically prepared BaSO 4 -Bi, BaSO 4 -Ag and BaSO 4 -Cu. It is deduced that in natural barite the narrow orange band with λ max = 625 nm. A = 40 nm and τ = 5 μs is connected with Bi 2+ center. The narrow violet band with λ max = 625 nm, Δ = 35 nm and τ = 1.7 ms is connected with Bi 3+ center. The broad red band with λ max = 635 nm, Δ = 140 nm and τ = 270 μs is connected with Ag + center. The broad red band with λ max = 750 nm, Δ = 110 nm and τ = 350 μs is connected with Cu + center. Such luminescence centers are firstly considered in minerals.

Rare earth ions, their spectroscopy of cryptates and related complexes in sol-gel glasses

The paper is devoted to the memory of my teacher and friend Christian K. Jorgensen who has written the pioneering works on complexes of Rare Earths (RE).

Luminescence of europium(III) compounds in zirconia xerogels

Abstract Incorporation of europium(III) compounds: the oxide and dibenzoylmethane chelate (Eu(DBM) 3 ) into zirconia xerogel glasses resulted in luminescent materials in which the DBM chelate was the most efficient in luminescence intensity. The luminescence intensity was even stronger in hybrid xerogels prepared from zirconium tetrapropoxide and 3-glycidoxypropyl-trimethoxysilan.

Synthesis and Characterization of Lead Sulfide Nanoparticles in Zirconia-Silica-Urethane Thin Films Prepared by the Sol-Gel Process

PbS nanocrystals (NCs) ranging between 4–8 nm were incorporated into Zirconium-Silica-Urethane (ZSUR) matrix obtained by the sol-gel method. The sizes of the particles were controlled by temperature treatment and by concentration of PbS in ZSUR matrix. The sizes of PbS NCs were determined by TEM measurements. The quantum size effect could also be extracted from optical absorption and photoluminescence spectra. The new matrix allows incorporation of up to 40% PbS forming a characteristic structure of dendrite by reacting lead acetate with ammonium thiocyanate in sol-gel matrix. The sol precursors of the matrix for Zirconium-Silica-Urethane contained zirconium oxide (ZrO2) matrix solution, tetramethoxysilane (TMOS), 3-glycid oxypropyl trimethoxysilane (GLYMO) and polyethylene urethane silane (PEUS) synthesized separately. The ZrO2 matrix solution was obtained from zirconium n-tetrapropoxide in propanol and acetic acid was used as a chelating agent to stabilize the zirconium oxide precursor.

Intensification of rare earths luminescence in glasses

Abstract Steady state and dynamic luminescence of Eu3+ cryptates, sulfides and oxides and of Tb3+ oxide and sulfide incorporated in a variety of glass films prepared by the sol–gel method allows to interpret the increase of luminescence in the complex ions compared to the simple oxides. The lifetimes of the emitting 5D0 state of europium and 5D4 state of terbium increases in the complexes. We discuss the mechanism of the excitation and nonradiative relaxation of the ions.

Confocal microscopy for characterization of porous sol-gel glasses incorporating luminescent dyes

Abstract Porous glasses were prepared using the sol–gel method. The mix of catalysts used during preparation was changed in order to produce two glasses with two different densities. Fluorescent dyes were incorporated into these glasses by diffusion into the glass. The resulting fluorescent glasses were characterized using confocal microscopy, which allows thin optical sections to be imaged at up to 200 μm below the sample surface. In addition, fluorescence recovery after photobleaching (FRAP) was used to demonstrate diffusion of the dye within wet samples. The results demonstrate the potential for non-invasive optical characterization of fluorescent sol–gel glasses, and in particular local measurement of diffusion coefficients within the glass matrix.