The primary goal of this review is to present a clear chemical perspective of borates in order to stimulate and facilitate the discovery of new borate-based optical materials. These materials, whic...

Borates: A Rich Source for Optical Materials.

Thermoluminescence properties of rare earth doped lithium magnesium borate phosphors

Gold nanoparticles (NPs) embedded in sodium antimony borate glass system were fabricated and their optical, physical, structural, ultrafast nonlinear optical properties were studied and analyzed. Metallic gold NPs were synthesized using thermal reducing agent Sb2O3 and demonstrated the reduction mechanism of Au3 +/Au+ → Au0 by using reduction potentials of corresponding redox system. UV–Visible spectroscopy measurements have revealed the characteristic surface plasmon resonance (SPR) of Au NPs at ~ 565 nm, attributed due to interband transition. The micrographs of High-Resolution Transmission Electron Microscopy (HR-TEM) confirmed the existence of uniformly distributed spherical shaped Au NPs with particle sizes in the 8–45 nm range with an average particle size of 25 nm. The ultrafast nonlinear optical properties of gold doped glasses were investigated using the Z-scan technique at a non-resonant wavelength (λ = 800 nm, 80 MHz repetition rate) with femtosecond (fs) Ti:sapphire laser pulses. Z-scan measurements of undoped glass depicted are verse saturable absorption (RSA) type of nonlinearity whereas the gold-doped glass demonstrated saturable absorption (SA) kind of nonlinearity due to intraband (sp → sp) transitions. The Z-scan data demonstrated that the investigated glasses are potential materials for the applications in nonlinear optics devices, particularly in optical switching devices.

Linear and nonlinear optical properties of gold nanoparticles doped borate glasses

Luminescence properties of the Sm-doped borate glasses

Introduction of XAFS

Synthesis, EPR and optical spectroscopy of the Cr-doped tetraborate glasses

Lithium and potassium–lithium tetraborate glasses doped with Cu (Li2B4O7:Cu and KLiB4O7:Cu) of high optical quality were obtained from polycrystalline compounds by fast cooling of the corresponding melt. Cu impurity was added to the Li2B4O7 and KLiB4O7 compounds in the form of a CuO oxide in the amounts of 0.4 and 1.6 mol.%. On the basis of EPR and optical spectroscopy (absorption, emission and luminescence excitation and kinetics) data analysis it was shown that the Cu impurity was incorporated into the tetraborate glass network as Cu2+ (3d9) and Cu+ (3d10) ions. The EPR spectra of Cu2+ centers were almost identical in glasses with the Li2B4O7:Cu and KLiB4O7:Cu compositions and were characteristic for glassy compounds. The Cu2+ EPR spectra parameters (g-values, hyperfine constants and peak-to-peak linewidths) in the Li2B4O7:Cu and KLiB4O7:Cu glasses were obtained at T = 300 K. The characteristic broad absorption band peaked near 750 nm was assigned to the 2B1g → 2B2g transition of the Cu2+ centers. An intense absorption in the UV region (λ

Synthesis and spectroscopy of tetraborate glasses doped with copper

A series of undoped borate glasses: Li2B4O7, LiKB4O7, LiB3O5, SrB4O7, and LiCaBO3 of high optical quality and chemical purity were obtained from the corresponding polycrystalline compounds using standard glass synthesis under technological conditions developed by the authors. The glasses were obtained by rapid cooling of molten crystalline material, which was heated to 100 K above the melting point to prevent crystallization and to exceed the glass transition point. The X-ray diffraction intensity profiles of the investigated glasses were typical of glassy compounds. The most typical intensity profile, consisting of almost symmetrical peaks, was observed in the case of Li2B4O7 and LiB3O5. Substitution and partial substitution of Li atoms by Sr and Ca atoms was accompanied by significant changes in the intensity profiles of the investigated glasses. Pair correlation functions and structural parameters (average interatomic distances and coordination number to oxygen) of the investigated glasses were evaluated and analyzed. Structural peculiarities of the investigated borate glasses are discussed in comparison with structural data available for their crystalline analogs.

/pdf/synthesis-and-x-ray-structural-investigation-of-undoped-g5pe50ct46.pdf

Synthesis and X-ray structural investigation of undoped borate glasses

Optical absorption of isotopically enriched Li2B4O7 single crystals irradiated by thermal neutrons

The electron paramagnetic resonance spectra of the glasses with Li2B4O7 and KLiB4O7 compositions doped with Mn and Cu were investigated. On the basis of obtained EPR spectra analysis it was shown that the Mn and Cu impurities are incorporated into the glass network as Mn (S5/2, 3d) and Cu (D5/2, 3d) ions. The Mn EPR spectra in the glasses with Li2B4O7 and KLiB4O7 compositions are characterised by the following parameters, measured at T = 300 K: isotropic g-factor (giso = 2.00± 0.05), isotropic hyperfine constant (Aiso = (8.65 ± 0.05) mT) and peak-to-peak linewidth of hyperfine components ∆Bpp = (3.50 ± 0.05) mT. The Cu EPR spectra in the glasses with Li2B4O7 and KLiB4O7 compositions, registered at T = 300 K are characterised by the same g-values (g‖ = 2.34 ± 0.05, g⊥ = 2.06 ± 0.05) and peak-to-peak line width of hyperfine components (∆B‖ pp = (5.11 ± 0.05) mT, ∆B⊥ pp = (1.80 ± 0.05) mT), whereas anisotropic hyperfine constants show some differences (A‖ = (14.28 ± 0.05) mT, A⊥ = (2.34 ± 0.05) mT for glass with Li2B4O7 composition and A‖ = (14.21±0.05) mT, A⊥ = (2.55±0.05) mT for glass with KLiB4O7 composition). The possible local structure of the Mn and Cu centres in the lithium and potassium–lithium tetraborate glass network has been considered.

/pdf/epr-spectroscopy-of-the-mn2-and-cu2-centres-in-lithium-and-2snqggrzgc.pdf

I.M. Teslyuk

Papers

Synthesis, EPR and optical spectroscopy of the Cr-doped tetraborate glasses

Synthesis and spectroscopy of tetraborate glasses doped with copper

Synthesis and X-ray structural investigation of undoped borate glasses

Optical absorption of isotopically enriched Li2B4O7 single crystals irradiated by thermal neutrons

EPR Spectroscopy of the Mn2+and Cu2+Centres in Lithium and Potassium-Lithium Tetraborate Glasses