Doped Borate Glasses Research Articles

Spectroscopic Studies of 50Bi<sub>2</sub>O<sub>3</sub>-(50 - x)B<sub>2</sub>O<sub>3</sub>-xSm<sub>2</sub>O<sub>3</sub> Glasses System

Sm3+ doped bismuth borate glasses of the composition (50 - x)B2O3:50Bi2O3:xSm2O3 (where x = 0.00, 0.50, 1.00, 1.50, 2.00 and 2.50 mol%) have been synthesized by conventional melt quenching technique. In order to understand the role of Sm2O3 inbismuth borate glasses, the density, the molar volume, the refractive index and the optical absorption were investigated. The results show that density, molar volume and refractive index of glasses increased with increasing Sm2O3 concentration. The increase of molar volume with Sm2O3 concentration is due to increase of non-bridging oxy- gen (NBOs) in the glass matrices. The optical absorption spectra were measured in the wavelength range 300 - 1100 nm and the optical band gaps were determined. It was found that the optical band gap decreased with the increase of Sm2O3 concentration. Moreover, the X-rays luminescence of Sm2O3 glasses samples were measured and shows emission band at 4G5/2→6H5/2 (569 nm),4G5/2→6H7/2 (598 nm),4G5/2→6H9/2 (641 nm) and4G5/2→6H11/2 (705 nm).

Dopant Concentration and Effective Atomic Number of Copper-Doped Potassium Borate Glasses

Copper-doped (0.5 mol%) and undoped potassium borate glasses have been prepared by the composition of (100-x)H3BO3+xK2CO3, where 10 ≤x≤ 30 mol % by the traditional melting quenching method. The structural pattern of glasses with different composition has been identified by X-ray diffraction (XRD). The glow curves were analysed to determine various characterizations of the TLDs. Identification of the compositions and concentrations and effective atomic number of undoped and doped potassium borate glass was carried out using scanning electron microscope analysis (SEM). The dopant concentrations are found to be 0.25 mol%, whileZeffare 11.42 and 10.48 for Cu-doped and undoped potassium borate glasses, respectively.

Local characterization of rare-earth-doped single microspheres by combined microtransmission and microphotoluminescence techniques

We present the optical characterization of single light emitting glass microspheres by means of an experimental setup that combines μ-transmission and μ-photoluminescence measurements without the need of optical fibers for excitation or detection purposes. We demonstrate that the results provided by both techniques are consistent among them and can provide complementary information regarding the active material properties (material losses and cross sections) and the passive resonator ones (radiative quality factors, group refractive indices, sphere radius, and pump power threshold for mode spectral shifting). This work addresses Nd3+ doped borate glass microspheres, but the reported studies could be realized in other rare-earth-doped glass microspheres as well.

Luminescence, structural and dielectric properties of Sm3+ impurities in strontium lithium bismuth borate glasses

In the present work, different concentrations of Sm3+doped strontium lithium bismuth borate glasses (SLBiB) have been prepared by melt quench technique and investigated their optical, structural and dielectric properties. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction and SEM analysis. The spectroscopic properties of these glasses were investigated by recording optical absorption, photoluminescence and decay curve analysis. Judd–Ofelt (J–O) theory has been applied for the f↔f transitions of Sm3+ ions to evaluate J–O intensity parameters, Ωλ (λ=2, 4 and 6). Using the J–O intensity parameters, radiative properties such as transition probabilities (AR), calculated branching ratios (β) and radiative lifetimes (τ) are estimated. From the emission spectra, effective bandwidths (Δλeff) and stimulated emission cross-sections (σp) have been obtained for observed emission levels. From the emission spectra, a strong reddish-orange emission corresponding to the transition, 4G5/2→6H7/2 was observed. The nature of decay curves of 4G5/2 level for different Sm3+concentrations in SLBiB glass has been analyzed. FTIR spectra were recorded to analyze the functional groups present in the glass matrix. From the dielectric properties, variation of dielectric constant, dielectric loss and ac conductivity of Sm3+ doped different glass samples with the variation of frequency was studied.

Spectroscopic investigations on Pr3+ and Nd3+ doped strontium–lithium–bismuth borate glasses

Spectroscopic investigations on different concentrations (0.1, 0.5, 1.0, 1.5 and 2.0mol%) of Pr3+ and Nd3+ doped strontium lithium bismuth borate glasses have been done. X-ray diffraction, SEM with EDS, absorption and luminescence spectra were recorded for all the glass matrices and analyzed. X-ray diffraction profiles and SEM images conformed amorphous nature of investigated glass samples. EDS spectra of host glass and Pr3+doped glass matrices gave information about the chemical composition of glass samples. From the absorption spectra of Pr3+ and Nd3+ ions, Judd–Ofelt (J–O) intensity parameters (Ωλ,λ=2, 4 and 6) have been calculated and compared with other glass matrices. The emission characteristics such as radiative lifetimes (τR), measured and calculated branching ratios (β) and stimulated emission cross-sections (σP) have been obtained for the observed emission transitions of Pr3+ and Nd3+ ions in the above glass matrix for all the concentrations. From the emission spectra of Pr3+ and Nd3+ doped glass matrices, the effect of concentration on the quenching of intensity of 1D2→3H4 transition of Pr3+ ion and 4F3/2→4I9/2, 4I11/2 and 4I13/2 transitions of Nd3+ have been studied and discussed.

Spectroscopic properties of Nd3+ doped borate glasses

Different glass matrices doped with Nd2O3 have been prepared by conventional melt quenching method with the molar compositions of (90-x) B2O3+(x-2) PbO+5 Bi2O3+5 Al2O3+2 Nd2O3, where x=10, 15, 20, 25 and 30. Optical absorption and emission spectra were recorded. Racah (E1, E2, E3), spin–orbit (ξ4f) and configuration interaction (α,β,γ) parameters have been evaluated from the spectral data. The bonding parameter (δ) obtained indicates that the bonds are covalent in nature. By applying least-square fitting, Judd–Ofelt parameters were evaluated from the intensities of the absorption spectra. Radiative transition probabilities (A), the total radiative transition probabilities (AT), radiative life-times (τR), branching ratios (βR) and absorption cross-sections (σa) have been computed for certain lasing levels. The stimulated emission cross-sections (σe) for the potential lasing transitions 4F3/2→4IJ (J=9/2, 11/2, 13/2) for all the glasses under study are reported.

Correlation between the dimensionality and the constants of elasticity of rare-earth doped borate glasses

This work was devoted to explore the correlation between the dimensionality and the computed theoretically constants of elasticity of borate based glasses doped with rareearth oxides. The dimensionality of the glassy network has been calculated in terms of the d ratio which is equal to 4 C 44 /K e and discussed in terms of the crosslink density and number of network bonds per unit volume of these glasses. Constants of elasticity were calculated in terms of the bond compression model and the Makishima-Mackenzie model. The average crosslink density, the number of networ k bonds per unit volume, the average stretchingforce constant, and the ratio of the estimated bulk modulus (Kbc) to the experimentally determined (Ke) have been calculated and discussed in terms of the bondcompre ssion model. Young's modulus, the packing density, and the dissociation energy have been calculated and analyzed in terms of the Makishima-Mackenzie model. The results showed that the computed elastic moduli and the dimensionality of the borate glasses containing La2O3 or Gd2O3 are strongly dependent on the concentration of the structural units of the constituent oxides and types of bonds between these units.

A new study on bismuth doped oxide glasses

Spectroscopic properties of bismuth doped borate, silicate and phosphate glasses have been reinvestigated in this work. It shows the typical decay time of Bi(3+) is around 500ns rather than 2.7-to-3.9 μs reported by Parke and Webb at room temperature. Introduction of higher content either alkali or alkali earth into borate glasses favors the Bi(3+) emission. As the contents increase excitation peak shifts regularly red while emission peak shows reverse trend. This, as revealed by Huang-Rhys factor, is due to the weakening of coupling between bismuth and glass host, and it can be interpreted within the frame of configurational coordinate diagrams. Differently, as bismuth concentration increases, both the excitation and emission shift red. The unknown origin of red emission from bismuth doped calcium or magnesium phosphate glass has been identified as Bi(2+) species on the basis of excitation spectrum and emission lifetime particularly after comparing with Bi(2+) doped materials. No near infrared (NIR) emission can be detected in these glasses within instrument limit.

Spectroscopic studies of tantalum doped borate glasses

Abstract Glasses with formula 30Li2O 60B2O3 xTa2O5 (10−x) Bi2O3 for x=0, 2, 4, 6 and 8 were prepared via normal melt quenching technique and characterized by refractive index and MDSC. Refractive index (μ) and glass transition temperature (Tg) are found to increase with increase in dopant concentration. Impedance spectra of the samples were recorded in the frequency range 100 Hz–5 MHz in the temperature range 175–275 °C. The plots are typical of those recorded for disordered systems. Conductivities and relaxation times are found to follow Arrhenius type of relation and activation energies are calculated. Optical absorption spectra were recorded in the wavelength range 200–900 nm range from which cutoff wavelength (λc) and optical band gap energy (Eg) are evaluated. λc is found to decrease while Eg to increase with increase in composition. FTIR spectra of the samples were recorded in the frequency range 400–1500 cm−1 which exhibit characteristic bands corresponding to BO3, BO4 stretching vibrations and BO bending vibration. Tightening of the structure is indicated by increase in the vibration of BO3 at the cost of BO4 for 8 mol% of Ta2O5. This is in support of the highest value of Tg for this sample among the series. Raman spectra of the samples were recorded in the frequency range 200–1200 cm−1. With successive addition of Ta2O5, increase in the vibration of Ta–O groups TaO6 groups to be responsible for observed increase in μ and Tg. An attempt is made to prepare tantalum doped borate glasses and study them by spectroscopic techniques.

The influence of cation additives on the NIR luminescence intensity of Er3+-doped borate glasses

Er3+-doped 25BaO-(25-x)SiO2-xAl2O3-25B2O3 transparent glasses are prepared with x = 0, 12.5 and 25 by a solid-state reaction. The Er-related NIR luminescence intensity, which corresponds to the transition of 4I15/2-4I13/2, is obviously altered with different silicon/aluminum ratios. The Judd-Ofelt parameters of the Er3+ ions are adopted to explain the intensity change in the NIR fluorescence, and the Raman scattering intensity versus the amount of Al and/or Si components are discussed. The spectra of the three samples are quite similar in the peak positions, but different in intensity. The maximal phonon density of state for the samples is calculated from the Raman spectra and is correlated to the NIR luminescence efficiency.

Spectroscopic and structural investigations of Er3+ doped zinc bismuth borate glasses

Erbium doped glasses having composition 20ZnO·xBi2O3·(79.5−x)B2O3 (15≤x≤35, x in mol%) were prepared by melt-quench technique. The spectroscopic properties were investigated using optical absorption and fluorescence spectra. The Judd–Ofelt intensity parameters, Ωλ (λ=2, 4, 6) were determined from the spectral intensities of absorption bands in order to calculate the radiative transition probability (AR), radiative life time (τR), branching ratio (βR) for various excited luminescent states. Using the emission spectra, full width at half maximum (FWHM), stimulated emission cross-section (σe) and figure of merit (FOM) were evaluated. The high values of Judd–Ofelt parameters indicate a substantial mixing of other electronic configuration into the 4fN configuration by the random crystal field in the glasses. All the intensity parameters (Ωλ) decrease with increase in Bi2O3 content and the effect is found to be most pronounced for Ω2 values. The structural investigations of the glasses were carried out by recording the IR transmission spectra. A correlation between the network forming units with the multi-phonon relaxation rate and hence with the possibility of radiative quantum efficiency has been made. In addition, various physical and optical parameters have been determined from the measured density and refractive index values.

Luminescence Property of Rare-Earth Doped Bismuth-Borate Glasses

We fabricated rare-earth doped bismuth borate glasses by using melt-quench technique. Two different types glass samples of xBi2O3: (100-x)B2O3 (x=30 and 50) were made to compare the luminescence properties. We measured x-ray luminescence of Bi-glass by using a x-ray tube. Several dopants were doped into the Bi-glass to measure the x-ray luminescence such as CeO2, Nd2O3, Er2O3, Dy2O3, Pr2O3, Sm2O3, Ho2O3, Gd2O3 and CeF3. Among them, Dy2O3, Nd2O3 and Sm2O3 doped Bi-glass emitted luminescence. We measured emission spectrum of each samples. Dy2O3 doped bi-glass has emission band at 482nm, 575nm, 662nm and 765nm. Nd2O3 doped bi-glass have emission band at 895nm and Sm2O3 doped Bi-glass has emission band at 569nm, 598nm, 641nm and 705nm. Moreover, Bi-glass scintillators with high light yield with good radiation hardness and low cost can be applied in high energy and nuclear physics, medical imaging, homeland security and radiation detection.

Spectroscopic investigations and physical properties of Mn 2+ doped mixed alkali zinc borate glasses

Spectroscopic investigations on Mn 2+ doped 20ZnO + xLi 2O + (30− x)Na 2O + 50B 2O 3 (5 ≤ x ≤ 25) (ZLNB) glasses reveal the non-linear behavior in their physical and structural properties. FT-IR spectra of ZLNB glasses reveal diborate units in the borate network. EPR spectra exhibit characteristic resonance signals of Mn 2+ ions. A well resolved six line hyperfine structure around g = 2.02 corresponds to the sites of Type II, and a weak broad shoulder around g = 2.7 followed by an unresolved intense signal at g = 4.25 corresponding to sites of Type I are observed for their respective transitions. A large value of zero-field splitting parameter ( D) is observed and it behaves non-linearly, reaches a maximum at x = 15 mol% with increase in Li 2O content. Δ g values reveal the ionic nature of glass systems. Optical absorption spectra suggest the distorted octahedral site symmetry of Mn 2+ ions in the host. Mixed alkali effect is evident in bandgap and Urbach energies.

Correlation between physical and structural properties of Co2+ doped mixed alkali zinc borate glasses

The physical and structural properties of Co2+ doped 20ZnO+xLi2O+(30−x)Na2O+50B2O3 (5≤×≤25) (ZLNB) glasses have been studied and correlated. The physical and structural parameters of all the glasses are evaluated and a non-linear behavior is observed. No sharp peaks are observed in XRD patterns of the glass samples which confirm the amorphous nature. FT-IR spectra of ZLNB glasses reveal diborate units in borate network. The optical absorption spectra suggest the site symmetry of Co2+ in the glasses is near octahedral. Crystal field and inter-electronic repulsion parameters are also evaluated. The optical band gap and Urbach energies exhibit the mixed alkali effect. All the samples are found to be strong and stable in structure with low values of Urbach energy which lie between 0.027eV and 0.039eV. The correlation between densities and Urbach energies of Co2+ doped ZLNB glasses with respect to Li2O content suggest a changeover conduction mechanism from electronic to ionic, with a diffusivity crossover point at x=15mol%.

Electrical properties and scaling behaviour of Sm3 + doped CaF2-bismuth borate glasses

The electrical properties for 20Bi2O3–60B2O3 (20−x)–CaF2–xSm2O3 glasses (0 ≤ x ≤ 2) were measured in the temperature range 297 K up to 629 K and in the frequency range 0·1–100 kHz. The d.c. and a.c. conductivity values and the dielectric loss (tan δ) values were found to increase with increasing Sm2O3 content, whereas the activation energy of conductivities and the dielectric constant decreased. These results were attributed to the introduction of the rare earth ions; promote the formation of a high number of non-bridging oxygen atoms, which facilitate the mobility of charge carriers. The frequency dependence of the a.c. conductivity follows the power law σ ac(ω) = Aω s. The frequency exponent (s) values (0·64 < s < 0·8) decrease with increasing temperature. This suggested that the a.c. conduction mechanism follows the correlated barrier hopping model (CBH). The dielectric constant (ε ′) and dielectric loss (tan δ values) were found to increase with increasing temperature and increasing Sm2O3 concentration in the glass. The a.c. conductivities as a function of frequency at different temperatures of a given glass superimposed onto a master curve (Roling scaling model). Furthermore, we have performed to scale the data as a function of composition. Two master curves were obtained, which suggested that there are differences in dominant charge carriers between glasses having Sm2O3 concentration ≥1 and glass of Sm2O3 concentration <1.

Optical and Physical Properties of Bismuth Borate Glasses Doped With Dy&lt;sup&gt;3+&lt;/sup&gt;

This study reports on physical and optical properties of Dy3+ doped bismuth borate glass. The glasses containing Dy3+ in (70-x)B2O3:30Bi2O3:xDy2O3 (where x = 0.0-2.5 mol%) have been prepared by melt-quenching method. In order to understand the role of Dy2O3 in these glasses, the density, molar volume and optical spectra were investigated. The results show that molar volume of the glasses increase with the increasing of Dy2O3 concentration and consequently generating more non-bridging oxygen (NBOs) into glass matrix. The absorption spectra of Dy3+ doped in bismuth borate glass correspond with several bands, which are assigned from the ground state, 6H15/2 to 6F3/2(761 nm), 6F5/2(806 nm), 6F7/2(907 nm), (6H7/2, 6F9/2)(1099 nm), (6F11/2, 6H9/2) (1283 nm) and 6H11/2(1695 nm). Moreover, the optical basicities were also theoretically determined.

Temperature dependence of the thermophysical properties of Neodymium doped borate glasses

We have experimentally measured the temperature dependence of the thermophysical properties of Nd 2O 3 doped borate glasses using a combination of the time resolved thermal lens technique with optical interferometry, thermal relaxation calorimetry and photoluminescence methods. Thermal diffusivity, thermal conductivity, fluorescence quantum efficiency, linear thermal expansion coefficient and thermal coefficient of the electronic polarizability were determined. The results showed the ability of these techniques to perform measurements very close to the glass transition region providing the absolute values of the measured physical quantities and the glass transition temperatures. In conclusion, it was observed that thermal lens and optical interferometry are advantageous methods for measurements as a function of temperature especially when low temperature scanning rate is required.

Thermo-optical characteristics and concentration quenching effects in Nd3+doped yttrium calcium borate glasses

In this work we present a comprehensive study of the spectroscopic and thermo-optical properties of a set of samples with composition xNd(2)O(3)-(5-x)Y(2)O(3-)40CaO-55B(2)O(3) (0 ≤ x ≤ 1.0 mol%). Their fluorescence quantum efficiency (η) values were determined using the thermal lens technique and the dependence on the ionic concentration was analyzed in terms of energy transfer processes, based on the Förster-Dexter model of multipolar ion-ion interactions. A maximum η = 0.54 was found to be substantially higher than for yttrium aluminoborate crystals and glasses with comparable Nd(3+) content. As for the thermo-optical properties of yttrium calcium borate, they are comparable to other well-known laser glasses. The obtained energy transfer microparameters and the weak dependence of η on the Nd(3+) concentration with a high optimum Nd(3+) concentration put this system as a strong candidate for photonics applications.

Optical and Structural Investigation of Bismuth Borate Glasses Doped With Dy3+

This paper reports on physical and optical properties of Dy3+ doped bismuth borate glasses. The glasses containing Dy3+ in (70-x)B2O3:30Bi2O3:xDy2O3 (where x = 0.0-2.5 mol%) have been prepared by melt-quenching method. In order to understand the role of Dy2O3 in these glasses, the density, molar volume, and optical spectra were investigated. The results show that molar volume of the glasses increase with the increasing of Dy2O3 concentration and consequently generating more non-bridging oxygen (NBOs) into glass matrix. The absorption spectra of Dy3+ doped in soda-lime silicate glass correspond with several bands, which are assigned from the ground state, 6H15/2 to 6F3/2(762nm), 6F5/2(805nm), 6F7/2(905nm), (6H7/2, 6F9/2) (1100nm), (6F11/2, 6H9/2)(1280nm), and 6H11/2(1695nm)

Optical and photophysical investigation of Meso, Proto and Hematoporphyrin(IX)dimethylester doped hybrid borate glasses

Hybrid borate glasses containing different concentrations (0.5–2.0 mg in 12 g of boric acid) of Mesoporphyrin(IX)dimethylester, Protoporphyrin(IX)dimethylester and Hematoporphyrin(IX)dimethylester were prepared by rapid melt quench technique at 230 °C. The hybrid glass samples were characterized by X-ray diffraction, optical absorption, steady state and time-resolved fluorescence emission. The optical absorption spectrum shows red-shift in Soret band along with change in Q-band pattern. The intensity of Q-band was found to increase with increase in the concentration of porphyrin in the glass. Steady state emission spectrum shows strong S 2→S 0 emission in the range 462–495 nm and blue shift in S 1→S 0 emission. Time-resolved fluorescence emission and fluorescence excitation spectra showed that different structures of porphyrins were exist in the glass samples. The variation in the spectral behaviour in the glass was correlated with those in solution medium and possible structures of porphyrin in borate glass were explored.