Doped Borophosphate Research Articles

Gamma ray shielding ability of Y3+ doped borophosphate glasses

Abstract Four selected Y2O3 doped borophosphate glass samples are prepared using melt quench technique. The structural properties such as density and molar volume are measured. The density (ρ) increases from 3.1384 to 3.4613 g/cm3 whereas molar volume (Vm) decreases from 60.84 to 55.00 cm3 mol−1 with addition of Y2O3 cm3 mol−1 content. The lattice of the glasses has been tested via X-ray diffraction which is a good technique for confirming the structural properties of these glasses and FTIR spectra. In addition, radiation shielding parameters for glasses were performed theoretically utilizing XCOM program for various gamma ray energy and experimentally using NaI(Ti) scintillation detector, The glasses were irradiated using energies 0.664, 1.174 and 1.334 MeV emitted by Cs-137 and Co-60 radioactive point sources respectively. Shielding parameters as leaner (μ), mass attenuation coefficients (μ/ρ) and half value layer (HVL), tenth value layer (TVL) and mean free path (MFP). The concentration of Y2O3 increases the (μ/ρ) increases, the HVL, TVL, and MFP values have inverse way. Superior radiation shielding is confirmed by the glass sample containing (3%, mole) of yttrium oxide. The results show that the borophosphate glasses doped with Y2O3 can be used to shield gamma rays.

Novel Tb3+ doped borophosphate glass scintillator for X-ray imaging

In this study, we introduce an efficient green-emitting material made from Tb3+ doped borophosphate scintillating glass for X-ray imaging. An influence of Tb2O3 concentration on the physical, optical, luminescent, and scintillation properties of glasses were investigated. The glass density and refractive index increase, while the molar volume and Tb3+ inter-ionic distance decreases with Tb2O3 addition. These glasses absorb the photons in range of UV, Vis, and NIR. The excitations by UV and X-ray on glasses causes the strong green emission centered around 545 nm by the 5D4 → 7F5 transition of Tb3+. The energy transfer from Gd3+ to Tb3+ was occurred in this emission. The glass doped with 4 mol% of Tb2O3 demonstrates the highest emission intensity at 545 nm due to the concentration quenching. The decay time of glasses are in few milliseconds. The integral X-ray scintillation efficiency of 4 mol% doped glass is 52% compared to that of BGO crystal. Additionally, this glass was proceeded in the X-ray imaging and yielded the image with satisfied resolution, characteristics and MTF values, compared to that obtained from YAG:Ce crystal. The developed glass has a potential for X-ray imaging applications, especially in the medical imaging, flaw detection, and security inspection.

Up-conversion and downconversion studies of Nd3+ doped borophosphate glasses

Neodymium doped borophosphate glasses have been synthesizsed by melt quenching technique to investigate their luminescence properties. The increase in density and decrease in molar volume with increasing concentration of Nd2O3 (0.1 mol% to 0.5 mol%) established the participation of Nd3+ in the glass structure. Non-crystalline nature of prepared glasses is confirmed by the absence of sharp peaks in X-ray diffraction spectra. The various structural units due to B2O3, P2O5, and PbO were identified by Fourier transform infrared spectroscopy. Ultraviolet visible absorption spectroscopy showed various absorption peaks/bands at 742 nm (4F7/2+4S3/2), 684 nm (4F9/2), 626 nm (2H11/2), 581 nm (4G5/2+2G7/2), 523 nm (4G7/2+4G9/2+ 2K13/2), 431 nm (2D5/2+2P1/2), 358 nm (4D3/2+4D5/2), 338 nm (2I11/2), and 315 (4D7/2+2I13/2+2L15/2). The optical parameters, namely indirect band gap, molar refractivity, molar polarizability, electronic polarizability and dielectric constant showed linear trend with increasing concentration of Nd2O3. Judd-Ofelt parameters followed Ω6> Ω4> Ω2 trend. The experimental and calculated oscillator strength for 584 nm is highest among all transitions because it is hypersensitive in nature. Upon 806 nm excitation, four visible peaks at 489 nm, 540 nm, 605 nm and 671 nm were observed. Excited state absorption up-conversion and energy transfer up-conversion mechanisms were responsible for visible up-conversion. At 338 nm, ultraviolet energy is downconverted to 448 nm, 529 nm, 591 nm. Commission International de I'Eclairage (CIE) chromaticity coordinates were evaluated from the up-conversion emission spectra and the coordinates lie in green region.

Effects of BaO and Bi2O3 on the optical and luminescence properties of Dy3+ doped borophosphate glasses

Barium borophosphate glass and bismuth borophosphate glass doped with 1 mol% dysprosium oxide were synthesized by melt-quenching technique at 1200 °C for 3 hrs. Both glasses were studied optical and luminescence properties to evaluate their potential for using as luminescence materials. The absorption spectra in the region of ultraviolet, visible and near-infrared from 300 to 2000 nm wavelength were investigated. The luminescence spectra showed the strong emission band at 573 nm (4F9/2 → 6H13/2) under 350 nm excitation wavelength, which the shapes of the emission bands are similar in both glasses. The optical absorption and luminescence intensity of barium borophosphate glass are higher than bismuth borophosphate glass. Also, it is observed that the direct and indirect bandgap values of barium borophosphate glass are found larger than bismuth borophosphate glass.

Structural and spectroscopic properties of Yb3+ doped borophosphate glasses for IR laser application

Ytterbium (Yb3+) doped borophosphate (BPYb) glasses have been prepared and studied by means of their physical, optical, structural and spectroscopic properties aiming laser performance parameters. The main structural groups, PO32−, P2O74− and BO4 of the borophosphates were analyzed through their FTIR-ATR and Raman spectra. A linear increment of the absorption coefficient and of the integrated emission intensity were observed with increase of Yb3+ ions. The absorption and emission cross-sections have been evaluated and reported. Decay lifetimes were found to decrease with the increase of Yb3+ ions. The evaluated laser performance parameters (Isat and Imin), figure of merit and cross-sections (absorption and emission) suggest that 0.5 mol% of Yb3+ doped borophosphate glass is the most appropriate candidate for solid state infrared (IR) laser applications.

Structural and luminescence studies on Dy3+ doped boro-phosphate glasses for white LED's and laser applications

The present work reports structural and luminescence studies on Dy3+ doped boro-phosphate glasses prepared with the chemical composition 51B2O3 + 10ZnO + 20Li2O + 9SrO + (10−x)P2O5 + xDy2O3 (where x = 0.1, 0.25, 0.5, 1 and 2 in wt%) by melt quenching technique. The presence of various stretching and bending vibrations of different borate and phosphate groups were identified from the FTIR spectral measurements. The Nephelauxetic ratios (β) and the bonding parameters (δ) calculated from the absorption spectra have been used to examine the bonding nature of the Dy–O bond in the prepared glasses. From the absorption spectra, optical band gap and Urbach's energy values were calculated to explore the electronic band structure. Judd-Ofelt (JO) theory have been employed to obtain the JO intensity parameters (Ω2, Ω4, Ω6) from the optical absorption spectra by using the experimental oscillator strength values. The luminescence spectra exhibit two intense emission bands at around 482 nm (blue) and 574 nm (yellow) corresponds to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions respectively. The radiative parameters were evaluated from the emission spectra using the JO intensity parameters and refractive index values. The emission spectra for different pumping wavelengths were characterized through Commission International d'Eclairage (CIE) 1931 chromaticity diagram to explore its suitability for WLED applications. The decay profile of the prepared glasses exhibit single exponential behavior for lower Dy3+ ion concentration and turn to exhibit non-exponential behavior for higher Dy3+ ion content due to the energy transfer process which takes place between the donor and acceptor ions. The energy transfer mechanism between the nearby Dy3+ ions has been analyzed by fitting the non-exponential decay curves into IH model and the results were discussed and compared with the reported literature.

Concentration dependent spectroscopic properties of Sm3+ doped borophosphate glasses

A new series of Sm3+ doped borophosphate glasses 50B2O3+20Li2CO3+10ZnO+9SrCO3+(11−x)P2O5+xSm2O3 (x=0.1, 0.25, 0.5, 1 and 2 in wt%) have been prepared by following melt quenching technique. The structural and optical properties of the prepared glasses were characterized through XRD, FTIR, absorption, luminescence and decay spectral measurements. The XRD spectrum exhibit broad diffusion at lower angles which reveal the amorphous nature and the presence of various functional groups such as POP bonds, BO vibrations in BO3 units and POH and BOH bonds in the title glasses were confirmed through the FTIR spectra. The nature of the metal–ligand bonding and the electronic band structure has been investigated using the absorption spectra. The Judd–Ofelt (JO) intensity parameters (Ω2, Ω4 and Ω6) were evaluated from the JO theory using the refractive index and the experimental oscillator strength values. The emission spectra exhibit four emission bands in the visible region corresponding to the 4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2 and 4G5/2→6H11/2 transitions by monitoring an excitation wavelength at 403nm. The emission spectra have been characterized through Commission International de I’Eclairage (CIE) 1931 chromaticity diagram to explore the dominant emission from the studied glasses. The radiative parameters such as transition probability (AR), branching ratios (βR) and stimulated emission cross-section (σPE) were obtained for the emission transitions using JO parameters and the results were discussed and compared with the reported literature.

Structural and luminescence studies of europium ions in lithium aluminium borophosphate glasses

Eu3+ doped borophosphate glasses with the chemical composition 20Li2O-30Al2O3-10B2O3-40P2O5-xEu2O3 (where x=0.05 mol.%, 0.1 mol.%, 1.0 mol.%, 1.5 mol.% and 2.0 mol.%) were prepared by conventional melt quenching technique. The structural and luminescence properties of the prepared Eu3+ doped borophosphate glasses were studied and compared with reported results. The XRD pattern showed the amorphous nature of the prepared glasses. Whereas, the FTIR spectra revealed the vibrational modes in the prepared glasses. The bonding parameters ( β¯ and δ) were calculated through the excitation spectra. Judd–Ofelt (J–O) intensity parameters were calculated from the emission spectra and were used to determine transition probability (A), stimulated emission cross-section (σEP), radiative lifetime (τR) and branching ratios (βexp) for the transition 5D0→7Fj (j=1, 2, 3 and 4) of Eu3+ ions. Furthermore, the luminescence intensity ratio (R) of 5D0→7F2 to 5D0→7F1 transition was also calculated. Transition 5D0→7F2 had the highest value of stimulated emission cross-section and branching ratios and the results were comparable with the reported values. This indicated that the present glass is promising host material for Eu3+ doped fiber amplifiers.

Composition-induced valence variation of europium and the photoluminescence properties for Eu2+ doped borophosphate luminous glass in air

A simultaneous blue-light and red-light emitting glass of SrO-B2O3-P2O5 doped with Eu2O3 is prepared in air, and then heat-treated without any reductive reagent. A transition combination is found to consist of a band emission peaked around 430 nm and a series of line emission from 593 nm to 611 nm, corresponding to the typical 4f6→5d 4f7 transition of Eu2+ and 5D0→7FJ (J = 0, 1, 2, 3, 4) transitions of Eu3+, respectively. Some unidentified crystals such as Sr (PO3)2 and SrB2O4 as hosts for Eu2+ with more stronger crystal field lead to this enhancement of photoluminescence (PL) intensity superior to the asprepared parent glass.

Spatial control of second-order optical susceptibility induced in thermally poled glasses

Second-order susceptibility thermally induced in poled glass samples was erased in doped borophosphate, lead silica, and fused silica glasses using an optical method. A simple law describes the temporal evolution and the spatial profile of the erased nonlinear region versus the intensity and profile of the erasure laser beam. A comparison is made between one and two photon absorption induced spatial profiles.

Spectroscopic Properties and Laser Performance Assessment of Yb3+ in Borophosphate Glasses

Absorption and emission properties of Yb3+ in borophosphate glasses of the (55‐x)P2O5·xB2O3·10ZnO·10BaO·20SrO·5Nb2O5·1Yb2O3 series (x= 0, 11, 22, 33, 44, and 55) have been investigated. To avoid the problem arising from the radiation trapping effect, the reciprocity method is employed to calculate the emission cross section. It is found that the spectroscopic properties of Yb3+ in our borophosphate glasses are sensitive to the Yb3+ site environments. In addition, the laser performance of the Yb3+‐doped borophosphate glasses has been assessed. And the borophosphate glasses with values of x= 33 and 55 appear to be superior to the phosphate glasses as Yb‐grain media.