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Alkali oxides and combination of alkali oxide–modified borosilicate glasses doped with rare earth ions such as Er3 + and Nd3 + ions were prepared using the conventional melt quenching technique, with the chemical composition 74.5 B2O3 + 10SiO2 + 5 MgO + R + 0.5 (Er2O3/Nd2O3) [where R = 10 (Li2O/Na2O/K2O) for series-A and series-C and R = 5 (Li2O + Na2O/Li2O + K2O/K2O + Na2O) for series-B and series-D]. Analysis of the prepared glasses was carried out by FTIR, optical absorption analysis, and photoluminescence (PL) analysis. An emission at 1539 nm corresponding to the 4I132 → 4I15/2 transition was observed for 0.5 mol% of Er3 +-doped BSMN and BSMLN glass. The emission spectrum of the Nd3 + ion–doped BSMN and BSMKN glasses has shown strong emission at 1070 nm (4F3/2 → 4I11/2) with an excitation wavelength λexci = 514.5 nm. In addition to that, the change in the absorption intensity with the addition of an alkali oxide and combinations of these alkali oxides to borosilicate glasses doped with Er3 + and Nd3 + ions was studied to optimize the potential alkali oxide–modified borosilicate glass.

Rice crop in coastal areas is very often subjected to major abiotic stresses like submergence, lodging of the crop caused by heavy rains or cyclones and salinity. Identification of genotypes tolerance to multiple abiotic stresses is needed to sustain under climate changed conditions. NILs of Pushyami (MTU 2336-62-25-38-16, MTU 2336-70-46-25-44) with Sub1 locus expressed tolerance to flash floods and also stagnant flooding and lodging resistance. NILs of Amara (MTU 2244-119-59- 63-40, MTU 2244-119-83-65, MTU 2244-39-10-44-1) having sub1 expressed tolerance to stagnant flooding, lodging resistance and moderate tolerance to salinity along with targeted trait of flash flood tolerance. NILs of Swarna (MTU 2546A- 13-1-6-1, MTU 2546A-12-18-1, MTU 2546A-34-1-9-1) expressed moderate tolerance to anaerobic germination along with its targeted lodging related traits. NILs of Cottondora sannalu (DST 8-162-4, DST 9-157-7, DST 8-4-4) expressed lodging, flash flood, anaerobic germination along with targeted trait of seedling stage salinity tolerance. The results showed that NILs possessing multiple abiotic stress tolerance would sustain even under climate changed conditions.

Using the melt quenching technique, a new Dy3+-doped alkali and mixed alkali based borosilicate glasses were prepared and characterized for spectroscopic properties to be used to assess the potentiality for the laser gain media. The FTIR, absorption and fluorescence spectra were investigated. According to the Judd-Ofelt theory, from the absorption spectra, the oscillator strengths were computed for the observed bands of Dy3+-doped borosilicate glasses. The spectroscopic properties, J–O intensity parameters and luminescence intensity of Dy3+-ions are compared in alkali and mixed alkali based borosilicate glasses. By the comparison, low δrms (0.323), high Ω2 (11.98 × 10−20 cm2), high Ω4/Ω6 (1.164) and enhanced luminescence intensity indicates that Dy3+-ions doped mixed alkali borosilicate (especially MgNaKBSi) glasses are potentially useful candidates for laser gain media.

In this article we report on alkali oxide modified borophosphate glasses doped with Eu3+and Tb3+ ions, with the chemical composition of 69.5 B2O3+10P2O5 + 10CaF2 + 5 Li2O+ 5ZnO+ R+ 0.5 Eu2O3 [where R = 5 (LiO2/Na2O/K2O)] have been prepared by conventional melt quenching technique, and the spectroscopic properties of the prepared glasses have been studied by XRD, Optical absorption, excitation and emission spectral analysis. XRD spectrum of the glasses have shown the amorphous nature of the glasses. The red emission corresponding to 5D0 → 7F2 (613 nm) transition was observed under the excitation of 394 nm wavelength, corresponding to Eu3+ ions, for all the prepared glasses. For Eu3+ ion doped glasses, emission bands were observed, such as; 5D1→ 7F1 (538 nm), 5D0→ 7F0 (580 nm), 5D0→ 7F1 (592 nm), 5D0→ 7F2 (613 nm), 5D0→ 7F3 (613 nm) and 5D0→ 7F4 (702 nm) are identified. In the case of Tb3+ ion doped glasses, four emission lines were observed, such as 5D4→ (7F6, 7F5, 7F4), which are located at 489 nm, 545 nm and 585 nm, respectively, after the samples were excited with 376 nm ultraviolet source. The green emission corresponding to 5D4 → 7F5 (543 nm) transition was observed under excitation wavelength 376 nm of the Tb3+ ions for all the prepared glasses. For all these emission bands, the decay curves were recorded to evaluate the emission life times. The mechanism underlying the observed emission from the glasses was explained in terms of energy levels.

In this work, currently used non-biodegradable mineral oil as a cutting fluid during machining is replaced with vegetable oil. In this work, duplex stainless steel is machined (turned) with the vegetable oils like coconut oil and neem oil. As a first step, vegetable oil based oil-in-water nano-emulsions were formulated using non-ionic surfactant (Tween-80) by ultrasonic emulsification method. In the second step, spindle speed, feed rate, depth of cut and type of cutting fluid are varied at three levels and Taguchi L27 machining experiments were performed. Measurement of surface roughness, tool wear and tool temperature were done as an output performance measure. From the results, it is evident that the order of influence for the improvement of tool wear and surface roughness are cutting fluid, feed rate and depth of cut respectively.

Four series of borosilicate glasses modified by alkali oxides and doped with Tb3+ and Sm3+ ions were prepared using the conventional melt quenching technique, with the chemical composition 74.5B2 O3 + 10SiO2 + 5MgO + R + 0.5(Tb2 O3 /Sm2 O3 ) [where R = 10(Li2 O /Na2 O/K2 O) for series A and C, and R = 5(Li2 O + Na2 O/Li2 O + K2 O/K2 O + Na2 O) for series B and D]. The X-ray diffraction (XRD) patterns of all the prepared glasses indicate their amorphous nature. The spectroscopic properties of the prepared glasses were studied by optical absorption analysis, photoluminescence excitation (PLE) and photoluminescence (PL) analysis. A green emission corresponding to the 5 D4 → 7 F5 (543 nm) transition of the Tb3+ ions was registered under excitation at 379 nm for series A and B glasses. The emission spectra of the Sm3+ ions with the series C and D glasses showed strong reddish-orange emission at 600 nm (4 G5/2 →6 H7/2 ) with an excitation wavelength λexci = 404 nm (6 H5/2 →4 F7/2 ). Furthermore, the change in the luminescence intensity with the addition of an alkali oxide and combinations of these alkali oxides to borosilicate glasses doped with Tb3+ and Sm3+ ions was studied to optimize the potential alkali-oxide-modified borosilicate glass.

Alkali oxide modified borosilicate glasses, doped with Eu3+ ions with the chemical composition of 74.5 B2O3+10SiO2+5 MgO+R+0.5 Eu2O3 [where R=10 (LiO2/Na2O/K2O) for series A and R=5 (Li2O+Na2O/Li2O+K2O/K2O+Na2O) for series B] have been prepared using the conventional melt quenching technique. Moreover, the spectroscopic properties of the prepared glasses have been studied by Fourier transform infrared spectroscopy (FTIR), optical absorption analysis, photoluminescence excitation (PLE) and Photoluminescence (PL) analysis. The red emission corresponding to the 5D0 →7F2 (614 nm) transition is registered under the excitation of 396 nm of the Eu3+ ions for all the prepared glasses. Based on the PLE and PL measurements, several spectroscopic properties were calculated, such as the fluorescence intensity ratio (R), Judd-Ofelt (J-O) intensity parameter (Ω2), peak emission wavelength ( λ P ), effective line width ( ∆ λ P ), radiative transition probabilities ( A R ), stimulated emission cross-section ( σ e ), experimental branching ratios ( β m ) and gain bandwidth parameters ( σ e × ∆ λ P ). The high values of σ e , β m A R for the 5D0→7F2 transition for our structures indicate that it may be a potential candidate for the red color center in display devices as well as a red emission laser with a wavelength of 614 nm.

In the present article, polycrystalline low Z (Zeff = 8.19) LiAlO2:Dy/Eu phosphor prepared by simple wet chemical method. Thermoluminescence and some of the dosimetric characteristics of Dy/Eu acti...

This article reports on the luminescence properties of rare earth (Dy3+ and Tm3+ )ions doped SrGa2 Si2 O8 phosphor were studied. SrGa2 Si2 O8 phosphors weresynthesizedby employing solid state reaction method.From the measured X-ray diffraction (XRD) pattern of the samplemonoclinic phase structure has been observed. Thermoluminescenceand Mechanoluminescence properties of the γ-ray irradiated samples have been studied. Photoluminescence spectra of Dy3+ activated SrGa2 Si2 O8 phosphor has been measured with an excitation wavelength at 348 nm,and it shows two emission bands at 483 and 574 nm due to 4 F9/2 → 6 H15/2 and 4 F9/2 → 6 H13/2 transitions respectively. Whereas the photoluminescence spectra of Tm3+ activated SrGa2 Si2 O8 phosphor has been measured with an excitation wavelength at 359 nm and it exhibits two emission bands at 454 and 472 nm due to 1 D2 → 3 F4 and1 G4 → 3 H6 transitions respectively. In thermoluminescence study, γ-irradiatedthermoluminescence glow curve of SrGa2 Si2 O8 :Dy3+ phosphor shows two well defined peaks at 293 °C (peak1)and 170 °C (peak2) whereas thermoluminescence glow curve of SrGa2 Si2 O8 :Tm3+ phosphor shows peaks at 292 °C (peak1) and 184 °C (peak2) indicating that two sets of traps are being activated within the particular temperature range and the trapping parameters associated with the prominent glow peaks of SrGa2 Si2 O8 :Dy3+ and SrGa2 Si2 O8 :Tm3+ are calculated using Chen's peak shape and initial rise method.From the Mechanoluminescence study, only one glow peak has been observed. Copyright © 2016 John Wiley & Sons, Ltd.

This paper reports on the BaSi6N8O:Eu3+ phosphor were prepared via modified two steps solid state diffusion technique in open air atmosphere and material was quenched at 1200°C for four hours. Eu3+ activated BaSi6N8O phosphor was characterized by XRD, which confirms the formation of the sample. From the Scanning electron microscope (SEM) images, the surface morphology of the sample has been studied. The photoluminescence (PL) spectra of BaSi6N8O:Eu3+ phosphor exhibits two emission bands at 614 nm (5D0→7F2) and at 587 nm (5D0→7F1) with an excitation wavelength of 396 nm. From the FTIR spectrum, bonding of atoms to each other and vibrational motions of molecules has been studied. ML was studied by dropping a piston on irradiated sample. From the ML glow curves single peak has been observed. ML intensity increases with activator concentration. Optimum ML has been observed for the sample having 1mole % of Eu ions.

This article reports on the optical characterization of Pr(3) (+) -, Er(3) (+) - and Nd(3) (+) -doped cadmium lead boro tellurite (CLBT) glasses prepared using the melt quenching method. The visible-near infrared (Vis-NIR) absorption spectra of these glasses were analyzed systematically. On measuring the NIR emission spectra of Er(3) (+) :CLBT glasses, a broad emission band centered at 1536 nm ((4) I13 /2 → (4) I15 /2 ) was observed, as were three NIR emission bands at 900 nm ((4) F3 /2 → (4) I9 /2 ), 1069 nm ((4) F3 /2 → (4) I11 /2 ) and 1338 nm ((4) F3 /2 → (4) I13 /2 ) from Nd(3) (+) :CLBT glasses and an NIR emission band at 1334 nm ((1) G4 → (3) H5 ) from Pr(3) (+) :CLBT glasses at an excitation wavelength (λex ) of 514.5 nm (Ar(+) laser). Copyright © 2016 John Wiley & Sons, Ltd.

The optical properties of borotellurite glasses doped with Nd3+ ions or codoped with Er3+–Yb3+ ions are investigated, in order to evaluate the potential application of these types of glass in laser systems and amplifier materials. The Judd–Ofelt (JO) model is used to determine the absorption intensities of both types of glass so as to establish the J–O intensity parameters ( Ω λ ). The J–O intensity parameters are then used to determine the various radiative parameters viz., the radiative transition probabilities ( A R ), branching ratios ( β R ), stimulated emission cross-sections ( σ e ), full width half maxima ( Δ λ p ) and radiative lifetimes ( τ R ) of both types of glass, which are also compared to the equivalent parameters for other host glasses. It has been shown that Yb3+ acts as an Er3+ sensitizer and contributes largely to the improvement of the spectroscopic properties of the glasses that is codoped with Er3+–Yb3+. The obtained values of A R , β R , τ R , σ e and Δ λ p for the Nd3+- and Er3+-doped glass show that both the 4F3/2 → 4I11/2 transition at 1.06 μm in the Nd3+ case and the 4I13/2 → 4I15/2 transition at 1.56 μm for the Er3+ case exhibit better NIR luminescence at a level suitable for photonic device applications. The potential of the glasses examined in this study, due to their promising gain media, is also discussed in terms of the development of solid state NIR lasers and optical amplification for telecommunication applications.

A series of Eu 3+ , Sm 3+ , and Dy 3+ ion doped magnesium yttrium silicate [MgY 4 Si 3 O 13 ] phosphors was synthesized using the solid-state reaction method with a grain size of approximately 500 nm in hexagonal symmetry. The photoluminescence (PL) spectra of the Eu 3+ , Sm 3+ , and Dy 3+ :MgY 4 Si 3 O 13 phosphors exhibit bright red, orange-red and yellow emissions at 615 nm ( 5 D 0 → 7 F 2 ), 603 nm ( 4 G 52 → 6 H 7/2 ), and 574 nm ( 4 F 9/2 → 6 H 13/2 ), respectively. The thermoluminescence (TL) of the phosphors displays the maximum intensity consistently at 10 mol% of the ion concentrations, with a single glow peak around 165 °C (Eu 3+ -activated phosphor), 230 °C (Sm 3+ -activated phosphor), and 230 °C (Dy 3+ -activated phosphor), respectively. The trap parameters such as the order of kinetics ( b ), activation energy ( E ), frequency factor ( S ), and Balarin parameter ( γ ) associated with the most intensive glow peak of these phosphors were finally determined by analyzing their line-shapes on the basis of Chen's method.

Praseodymium (Pr3+) ions doped Barium Gadolinium Titanate (BaGd2Ti4O12) powder ceramics were prepared through high temperature traditional solid state reaction method. The structural, elemental analysis, Photoluminescence and Thermoluminescence properties were studied systematically. From the X- ray diffraction profile, it has been observed that the crystallized powder ceramics is in the form of orthorhombic structure. The average grain size of the prepared powder ceramics were observed in the range of ∼200-300 nm from the SEM images. PL Spectra of Pr3+: BaGd2Ti4O12 ceramics have shown strong red emission at 680 nm with the excitation wave length 450 nm. TL peaks at 351K has been observed in the TL spectrum.

Rare-earth (Tb3+) ions doped zinc lithium bismuth borate (ZLiBiB) glasses have been prepared by melt quenching method. From the FTIR spectrum, the functional groups have been identified. From the measurements of X-ray diffraction (XRD), differential scanning calorimeter (DSC) profiles of these glasses have been carried out. In case of Tb3+:ZLiBiB glasses emission transitions such as 5D4→ 7F6 (489 nm), 5D4→ 7F5 (545 nm), 5D4→ 7F4 (584 nm) and 5D4→ 7F3 (622 nm) have been identified. Among these, the transition at 542 nm has shown a bright green emission. The emission mechanism of Tb3+ doped ZLiBiB glasses has been explained in terms of energy level diagram.

This article reports on the synthesis, photoluminescence and thermoluminescence properties of samarium and dysprosium ions doped barium gadolinium titanate powder ceramics. The prepared samples were characterized by X- ray diffraction spectrum and it is observed that Sm3+ and Dy3+ ions doped barium gadolinium titanate powder ceramics are orthorhombic structure. From the SEM images of Sm3+ and Dy3+: BaGd2Ti4O12 ceramics, it is observed that the average grain size in the range ∼200-300 nm. The elements present in the composition are confirmed by the EDAX profiles and functional groups have been identified by using Fourier Transform Infrared spectroscopy. Photoluminescence spectra of Sm3+: BaGd2Ti4O12 ceramics have shown strong reddish- orange emission at 598 nm (4G5/2→6H7/2) with an excitation wavelength λexci = 408 nm (6H5/2→4F7/2) and Dy3+: BaGd2Ti4O12 ceramics have shown yellow emission at 587 nm (4F9/2→ 6H13/2) with an excitation wavelength λexci = 427 nm (6H15/2 → 4G11/2). Thermoluminescence (TL) natur...

This article deals with the spectral analysis of Er3+ and Nd3+ ions doped zinc lithium bismuth borate (ZLiBiB) glasses prepared by melt quenching method. The Vis-NIR absorption spectra of these glasses have been analyzed systematically. Judd-Ofelt intensity parameters Ωλ (λ = 2, 4, 6) have been evaluated and used to compute the radiative properties of emission transitions of Er3+ and Nd3+: ZLiBiB glasses. The NIR emission spectra of Er3+ and Nd3+: ZLiBiB glasses were measured with an Ar+ laser (514.5 nm) as the excitation source. From the NIR emission spectrum of Er3+: ZLiBiB glass a broad emission band centered at 1,538 nm (4I13/2 → 4I15/2) is observed and from Nd3+: ZLiBiB glass, three NIR emission bands at 898, 1,070 and 1,338 nm are observed which are assigned to the transitions (4F3/2 → 4I9/2), (4F3/2 → 4I11/2) and (4F3/2 → 4I13/2) respectively.

Barium-gadolinium-titanate (BaGd2 Ti4 O12) powder ceramics doped with rare-earth ions (Eu(3+) and Tb(3+)) were synthesized by a solid-state reaction method. From the X-ray diffraction spectrum, it was observed that Eu(3+) and Tb(3+):BaGd2 Ti4 O12 powder ceramics are crystallized in the form of an orthorhombic structure. Scanning electron microscopy image shows that the particles are agglomerated and the particle size is about 200 nm. Eu(3+) - and Tb(3+) -doped BaGd2 Ti4 O12 powder ceramics were examined by energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, photoluminescence and thermoluminescence (TL) spectra. Emission spectra of Eu(3+)-doped BaGd2 Ti4 O12 powder ceramics showed bright red emission at 613 nm ((5)D0 →(7)F2) with an excitation wavelength λ(exci) = 408 nm ((7)F0 → (5)D3) and Tb(3+):BaGd2 Ti4 O12 ceramic powder has shown green emission at 534 nm ((5)D4 → (7)F5) with an excitation wavelength λ(exci) = 331 nm (((7)F6 → (5)D1). TL spectra show that Eu(3+) and Tb(3+) ions affect TL sensitivity.

Niobium containing tellurium calcium zinc borate (TCZNB) glasses doped with different concentrations of Dy 3+ ions were prepared by the melt quenching method and their optical properties have been studied. The Judd–Ofelt (J–O) intensity parameters Ω t ( t =2, 4 and 6) were calculated using the least square fit method. Based on the magnitude of Ω 2 parameter the hypersensitivity of 6 H 15/2 → 6 F 11/2 has also been discussed. From the evaluated J–O intensity parameters as well as from the emission and lifetime measurements, radiative transition properties such as radiative transition probability rates and branching ratios were calculated for 4 F 9/2 excited level. It is found that for Dy 3+ ion, the transition 4 F 9/2 → 6 H 13/2 shows highest emission cross-section at 1.0 mol% TCZNB glass matrix. From the visible luminescence spectra, yellow to blue ( Y / B ) intensity ratios and chromaticity color coordinates were also estimated. The TCZNB glasses exhibit good luminescence properties and are suitable for generation of white light.

MVO 4 : Al 3+ , Eu 3+ @ SiO 2 powder phosphors have been synthesized by a modified colloidal precipitation technique followed by calcination. Luminescence optimization was fine tuned mainly in three stages, by investigating the effects of: (i) host composition (Gd, Y and Gd/Y), (ii) co-dopant Al 3+ as a sensitizer and finally (iii) with SiO 2 coating as a surface protecting layer. XRD data revealed that the produced phosphors were well crystalline and possess body centered tetragonal phase. SEM micrographs illustrate that the synthesized phosphor particles are loosely bound with tetragonal like morphology and consists 1–5 μm dia grain size. Silica coating on phosphor particles were characterized by SEM/EDAX, TEM, FT-IR and PL measurements. An intense charge transfer excitation band owing to VO 4 3− has dominated the f–f transitions of Eu 3+ ions. The emission intensities of the hypersensitive 5 D 0 → 7 F 2 transitions are stronger than the magnetic dipole 5 D 0 → 7 F 1 , indicates lowering of inversion symmetry in the vicinity of Eu 3+ , ions. Red color richness owing to the efficient energy transfer from Al 3+ to Eu 3+ with Y 0.94 VO 4 : Al 3+ 0.01 , Eu 3+ 0.05 phosphor were enhanced significantly by 3 times stronger than the phosphor Y 0.95 VO 4 : Eu 3+ 0.05 , which was further increased 1.2 times with SiO 2 protecting layer.

Enhanced red luminescence in LnVO 4 : Bi 3+ , Eu 3+ @ SiO 2 phosphors has been improved mainly in three stages by investigating the effects of: (i) host composition (Gd, Y and Gd/Y), (ii) co-doping Bi 3+ as a sensitizer and finally (iii) SiO 2 shell coating. XRD data revealed that the produced phosphors possess crystalline, pure phase with tetragonal structure. Silica coating on phosphor particles have been characterized by SEM/EDAX, TEM, PL and with the presence Si–O–Si, Si–O vibrational modes from the FT-IR spectra. Absorption band edges due to VO 4 3− , shifted to higher wavelength with Bi-concentration, owing to the presence of Bi–O bond in addition to V–O. The emission intensities of 5 D 0 → 7 F 2 transition are stronger than 5 D 0 → 7 F 1 ; indicating the lower inversion symmetry near Eu 3+ , ions. Red emission intensity due to the efficient energy transfer from VO 4 3− to Eu 3+ via Bi 3+ ions in Y 0.949 VO 4 : Bi 3+ 0.001 , Eu 3+ 0.05 phosphor was improved significantly, i.e. 1.6 times compared to Y 0.95 VO 4 : Eu 3+ 0.05 . This was further enhanced 2.25 times by SiO 2 shell coating. Thus, Y 0.949 VO 4 : Bi 3+ 0.001 , Eu 3+ 0.05 @ SiO 2 are suggested to be a promising red phosphor for application in display devices or lighting.

This article reports on the optical properties of cadmium bismuth borate (CdBiB) glasses doped with various concentrations of Sm 3+ ions. FT-IR spectra of Sm 3+ :CdBiB glasses have been used to identify the functional groups present in the composition of the glasses. The emission spectra of Sm 3+ :CdBiB glasses have shown an intense reddish-orange emission at 600 nm ( 4 G 5/2 → 6 H 7/2 ). From the absorption spectrum, the experimental oscillator strengths were determined and have been used to calculate the Judd–Ofelt (J–O) intensity parameters. By using the J–O intensity parameters, various radiative properties have been studied and computed for the various transitions of Sm 3+ :CdBiB glasses. Based on the values of stimulated emission cross section, radiative transition rate and the branching ratio of the emission transition 4 G 5/2 → 6 H 7/2 , it is suggested that 1.0 mol% of Sm 3+ :CdBiB glass is the promising luminescent material towards lasing applications. The nature of luminescence decay curves of 4 G 5/2 level with different concentrations of Sm 3+ :CdBiB glasses are also reported.

A series of Sm 3+ and Dy 3+ ions activated Ba 3 Y 2 WO 9 (BaYW) ceramics were synthesized by using a conventional solid state reaction method. Photoluminescence spectra of Sm 3+ and Dy 3+ : BaYW ceramics have shown strong reddish-orange (596 nm) and blue (494 nm) emission. The tetragonal phase structure has been assigned to the prepared ceramics by the measurement of X-ray diffraction (XRD) profiles. Agglomeration and the nanometer particle size (130 nm to 220 nm) were observed from the SEM images of the ceramics. The functional groups like OH, CO 3 , WO bonds, YO bonds and the elements such as Ba, Y, W, O, Sm and Dy present in the prepared ceramics were identified by measuring the FTIR and EDAX spectra. In this contribution, we have reported the emission properties of Sm 3+ and Dy 3+ : BaYW ceramics to explore them as novel optical materials and also reported the effect of Sm 3+ and Dy 3+ concentration on the luminescence behavior. Decay kinetics of the prominent emission transitions of Sm 3+ and Dy 3+ : BaYW ceramics are also discussed.

Rare earth (Er 3+ and Nd 3+ ) ions doped cadmium lithium boro tellurite (CLiBT) glasses were prepared by melt quenching method. The vis–NIR absorption spectra of these glasses have been analyzed systematically. Judd–Ofelt intensity parameters Ω λ ( λ = 2, 4, 6) have been evaluated and used to compute the radiative properties of emission transitions of Er 3+ and Nd 3+ : CLiBT glasses. From the NIR emission spectra of Er 3+ : CLiBT glasses a broad emission band centered at 1538 nm ( 4 I 13/2 → 4 I 15/2 ) is observed and from Nd 3+ : CLiBT glasses, three NIR emission bands at 898 nm ( 4 F 3/2 → 4 I 9/2 ), 1070 nm ( 4 F 3/2 → 4 I 11/2 ) and 1338 nm ( 4 F 3/2 → 4 I 13/2 ) are observed with an excitation wavelength λ exci = 514.5 nm (Ar + Laser). The FWHM and stimulated emission cross-section values are calculated for Er 3+ and Nd 3+ : CLiBT glasses. FWHM × σ e P values are also calculated for Er 3+ : CLiBT glasses.

This article reports on the optical absorption and photoluminescence analysis of different concentrations of Dy3+ ions doped cadmium bismuth borate (CdBiB) glasses prepared by melt quenching method. The emission spectra of Dy3+: CdBiB glasses have shown a yellow emission at 574 nm (4F9/2 → 6H13/2). The emission intensity was maximum for 1.0 mol% of Dy3+: CdBiB glass and after this optimum concentration, the phenomenon of concentration quenching was observed. From the absorption spectrum, by applying the J-O theory, the experimental oscillator strengths were determined and have been used to calculate the J–O intensity parameters. By using the J–O intensity parameters various radiative properties such as branching ratios (βR), measured branching ratios (βm), spontaneous emission transition probability (A), radiative transition rate (AT), radiative life time (τR), measured life time (τm), effective band-width (Δλp) and stimulated emission cross sections have been calculated for the various transitions of Dy3...

This article reports on the luminescence properties of rare earth (Dy

This study reports on the concentration dependent fluorescence properties of Tb3+-doped lead containing calcium zinc sodium fluoroborate (LCZSFB) glasses and are analyzed by DSC, FT-IR, FT-Raman, optical absorption, emission and decay curve spectra. Co-existence of trigonal BO3 and tetrahedral BO4 units was evidenced by FT-IR and Raman spectroscopy. Judd–Ofelt theory was applied to the experimental oscillator strengths to evaluate the J–O intensity parameters. The fluorescence spectra of Tb3+-doped glasses have revealed prominent blue and green emissions originating from 5D3 and 5D4 excited levels to 7FJ ground state multiplet, respectively. The luminescent intensity of the transitions originating from 5D4 state increases with increase of Tb3+ concentration and no quenching effect is noticed up to 2 mol% of Tb3+ ions. Chromaticity color coordinates have been calculated and the dominant emission in the green region is discussed. The nature of decay curves of 5D4 level for different Tb3+ ion concentration in all LCZSFB glasses has been analyzed. Using the J–O intensity parameters as well as from the emission and decay curve measurements, various radiative and fluorescence properties have been calculated for the 5D4 fluorescent level. Based on these results, the utility of Tb3+ ions doped LCZSFB glasses as laser active materials for high intensity emissions in the green region is discussed.

This article reports on the optical properties of 0.5% mol of Sm3+, Dy3+ ion-doped B2O3-TeO2-Li2O-AlF3 (LiAlFBT) glasses. The glass samples were characterized by optical absorption and emission spectra. Judd-Ofelt theory was applied to analyze the optical absorption spectra and calculate the intensity parameters and radiative properties of the emission transitions. The emission spectra of Sm3+ and Dy3+:LiAlFBT glasses showed a bright reddish-orange emission at 598 nm (4G5/2 6H7/2) and an intense yellow emission at 574 nm (4F9/2 6H13/2), respectively. Full width at half maximum (FWHM), stimulated emission cross section, gain bandwidth and optical gain values were also calculated to extend the applications of the Sm3+ and Dy3+:LiAlFBT glasses. Copyright © 2012 John Wiley & Sons, Ltd.

This paper reports on the preparation and spectral properties of europium (Eu3+) and terbium (Tb3+) ions doped cadmium lead boro tellurite (CLBT) glasses. For reference glasses, physical properties have been evaluated. From the [measurements of X-ray diffraction (XRD), glass amorphous nature of these [glasses has been studied. From the emission spectra of Eu3+: CLBT glasses, five [transitions (5D0 → 7F0, 7F1, 7F2, 7F3 and 7F4) at 579, 591, 613, 652 and 701 nm are observed with λexci = 392 nm (7F0 → 5L6) and in the case of Tb3+: CLBT glasses, four emission transitions 5D4 → (7F6, 7F5, 7F4 and 7F3) are observed at 489, 543, 584 and 621nm respectively monitered with λexci = 376 nm (7F6 → 5G6).

5 mol% of Pr3+ and Tm3+ ions activated calcium gadolinium tungstate (Ca2Gd2W3O14) phosphors were synthesized by traditional solid state reaction method. Crystalline phase structure was identified from the X-ray diffraction (XRD) profiles. From the scanning electron microscopy (SEM) images, we have observed the agglomeration of the particles, and average grain size is around 40–300 nm. Using the energy dispersive X-ray analysis (EDAX) and Fourier transform infrared (FTIR) spectra, identified the elements and functional groups present in the prepared phosphors. The emission spectrum of Pr3+: Ca2Gd2W3O14 powder phosphors have shown an intense red emission at 615 nm with the excitation wavelength λexci=450 nm and thus these red color emitting powder phosphors are used as one of the components in the preparation of WLEDs. The excitation spectrum of Tm3+: Ca2Gd2W3O14 powder phosphor has shown a ligand to metal charge transfer (W–O) band (LMCT) within the WO42− group. Emission spectrum of Tm3+: Ca2Gd2W3O14 phosphors have shown blue emissions at 453 nm (1D2→3F4).

Structural, morphological and optical properties of rare earth ions (RE 3+ =Sm 3+ or Dy 3+ ) activated Ca 3 Ga 2 Si 3 O 12 (CaGaSi) phosphors synthesized by the sol–gel method are reported. XRD results confirmed the cubic phase structure of RE 3+ :CaGaSi phosphors. From the SEM images of RE 3+ :CaGaSi phosphors, it is observed that the particles are agglomerated. Photoluminescence spectra of Sm 3+ :CaGaSi phosphors have shown bright orange red emission at 598 nm ( 4 G 5/2 → 6 H 7/2 ) with an excitation wavelength of λ exci =401 nm. In the case of Dy 3+ :CaGaSi phosphors bright yellow emission has been observed at 574 nm ( 4 F 9/2 → 6 H 13/2 ) with λ exci =451 nm. From the PL spectral results, the rare earth ion concentration of CaGaSi phosphors is optimized.

A new series of Eu3+ ions-activated calcium gadolinium tungstate [Ca2Gd2W3O14] phosphors were synthesized by conventional solid-state reaction method. The X-ray diffraction patterns of the powder samples indicate that the Eu3+: Ca2Gd2W3O14 phosphors are of tetragonal structure. The prepared phosphors were well characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL), and mechanoluminescence (ML) spectra. PL spectra of Eu3+: Ca2Gd2W3O14 powder phosphors have shown strong red emission at 615 nm (5D0 → 7F2) with an excitation wavelength λexci = 392 nm (7F0 → 5L6). The energy transfer from tungstate groups to europium ions has also reported. Mechanoluminescence studies of Eu3+: Ca2Gd2W3O14 phosphors have also been explained systematically.

Novel green nanophosphors Ca2Gd2W3O14: Tb3+ were synthesized by solid state reaction method. From the X-ray diffraction profiles it is observed that Tb3+: Ca2Gd2W3O14 phosphors were crystallized in the form of tetragonal structure. The scanning electron microscopy (SEM) image shows that the particle size is at around 300 nm. In addition to these the prepared powder phosphors were also examined by the energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and mechanoluminescence (ML) spectra. Emission spectra of Tb3+: Ca2Gd2W3O14 nanophosphors have shown bright green emission at 545 nm (5D4 → 7F5) with an excitation wavelength λexci = 374 nm (7F6 → 5G6). ML spectra shows the radiation effect on the Ca2Gd2W3O14: Tb3+ nanophosphors and from that it was observed that these phosphors are very less sensitive for lower exposure.

This article reports on the optical properties of Er3+ ions doped CdO–Bi2O3–B2O3 (CdBiB) glasses. The materials were characterized by optical absorption and emission spectra. By using Judd–Ofelt theory, the intensity parameters Ωλ (λ = 2, 4, 6) and also oscillatory strengths were calculated from the absorption spectra. The results were used to compute the radiative properties of Er3+:CdBiB glasses. The concentration quenching and energy transfer from Yb3+–Er3+ were explained. The stimulated emission cross-section, full width at half maximum (FWHM) and FWHM × values are also calculated for all the Er3+:CdBiB glasses. Copyright © 2011 John Wiley & Sons, Ltd.

Rare earth ions (Sm 3+ and Dy 3+ ) activated calcium gadolinium tungstate [Ca 2 Gd 2 W 3 O 14 ] powder phosphors were synthesized by solid state reaction method at 1000 °C. The obtained phosphors were characterized by XRD, SEM, EDAX, FTIR and PL spectroscopy. The results of XRD patterns indicate the tetragonal phase structure of Sm 3+ and Dy 3+ : Ca 2 Gd 2 W 3 O 14 phosphors. From the SEM images of Sm 3+ and Dy 3+ : Ca 2 Gd 2 W 3 O 14 phosphors, it is observed that the average grain size is in the range 100–250 nm. The functional groups are identified by using the FTIR spectra and the elements present in the composition are confirmed by the EDAX profiles. Emission spectra of Sm 3+ : Ca 2 Gd 2 W 3 O 14 powder phosphors have shown strong red emission at 646 nm ( 4 G 5/2 → 6 H 9/2 ) with an excitation wavelength λ exci = 402 nm ( 6 H 5/2 → 4 F 7/2 ) and Dy 3+ : Ca 2 Gd 2 W 3 O 14 phosphors have shown yellow emission at 574 nm ( 4 F 9/2 → 6 H 13/2 ) with an excitation wavelength λ exci = 385 nm ( 6 H 15/2 → 4 I 13/2 ).

This article reports on the optical absorption and NIR emission properties of Nd3+ ions doped CdO–Bi2O3–B2O3 (CdBiB) glasses. Judd–Ofelt theory has been applied to calculate the oscillatory strengths of the transitions in the absorption spectra and also the intensity parameters Ωλ (λ = 2, 4, and 6). These results were then used to compute the radiative properties of emission transitions of Nd3+:CdBiB glasses. From the NIR emission spectra of Nd3+:CdBiB glasses, three NIR emission bands are observed at 900, 1069, and 1338 nm and assigned to the transitions (4F3/2 → 4I9/2), (4F3/2 → 4I11/2), and (4F3/2 → 4I13/2), respectively. The concentration quenching phenomenon has also been explained. The stimulated emission cross-section and FWHM values were calculated for all the Nd3+:CdBiB glasses.

Rare-earth ions (Eu3+, Tb3+) activated magnesium calcium bismuth titanate [(MgCa)2Bi4Ti5O20] ceramics were prepared by conventional solid state reaction method for their structural and luminescence properties. By using XRD patterns, the structural properties of ceramic powders have been analyzed. Emission spectrum of Eu3+:(MgCa)2Bi4Ti5O20 ceramic powder has shown strong red emission at 615 nm (5D0 → 7F2) with an excitation wavelength λexci = 393 nm and Tb3+:(MgCa)2Bi4Ti5O20 ceramic powder has shown green emission at 542 nm (5D4 → 7F5) with an excitation wavelength λexci = 376 nm. In addition, from the measurements of scanning electron microscopy (SEM), Fourier transform-infrared (FTIR) and energy dispersive X-ray analysis (EDAX) results the morphology, structure and elemental analysis of these powder ceramics have been studied.

Eu 3+ ions activated Ba 3 Y 2 WO 9 ceramics were synthesized using a solid state reaction method and the luminescent characteristics were investigated. Photoluminescence spectra of Eu 3+ : Ba 3 Y 2 WO 9 ceramics have shown strong red emission at 615 nm ( 5 D 0 → 7 F 2 ) with an excitation wavelength λ exci =392 nm ( 7 F 0 → 5 L 6 ). These powder ceramics have been characterized for their structures and morphology from the measurements of X-ray diffraction (XRD) and scanning electron microscope (SEM) results. Functional groups are identified using Fourier transform infrared (FTIR) measurements and elemental analysis has been carried out from the measurements of energy dispersive X-ray analysis (EDAX).

Pr3+ and Tm3+ (0.2 mol %) ions doped magnesium calcium bismuth titanate [(MgCa)2 Bi4Ti5O20] ceramics were synthesized by conventional solid state reaction method. The structural and morphological properties of prepared ceramic powders were studied by using XRD and SEM profiles. The elemental analysis and FTIR spectra of the prepared ceramics have been analyzed. Emission spectrum of Pr3+: (MgCa)2Bi4Ti5O20 ceramic powder has shown strong red emission at 614 nm (3P0 → 3H6) with an excitation wavelength λexci = 452 nm (3H4 → 3P2) and Tm3+: (MgCa)2Bi4Ti5O20 ceramic powder has shown blue emission at 477 nm (1G4 → 3H6) with an excitation wavelength λexci = 367 nm (3H6 → 1D2).

Lead containing calcium zinc sodium fluoroborate glasses (LCZSFB) with molar composition of 20PbO+5CaO+5ZnO+10NaF+(60−x) B2O3+x Sm2O3, (x=0.1, 0.25, 0.5, 1.0 and 2.0 mol%) were prepared and investigated by the XRD, FTIR, optical absorption, photoluminescence and decay curve analysis. Judd–Ofelt theory was applied to the experimental oscillator strengths to evaluate the phenomenological J–O intensity parameters Ωλ (λ=2, 4 and 6). Using the J–O intensity parameters as well as from the emission and decay measurements, various radiative parameters such as transition probabilities (AR), radiative lifetimes (τR), measured lifetimes (τm), calculated branching ratios (βR), measured branching ratios (βm), effective bandwidth (Δλeff) and stimulated emission cross sections σ(λp) have been calculated for the excited 4G5/2 luminescent level. The nature of decay curves of 4G5/2 level for different Sm3+ ion concentrations in all LCZSFB glasses has been analyzed and the lifetimes are noticed to decrease with increase of concentration. The concentration quenching has been attributed to the energy transfer through the cross-relaxation between Sm3+ ions. Based on these results, the utility of Sm3+ ions doped lead containing fluoroborate glasses as laser active materials in the visible region is discussed.

Rare earth ions (Eu(3+) or Tb(3+) )-activated Ca(3) Ga(2) Si(3) O(12) (CaGaSi) phosphors were synthesized by using a sol-gel method. Photoluminescence spectra of Eu(3+):CaGaSi phosphors exhibited five emission bands at 578, 592, 612, 652 and 701 nm, which were assigned to the transitions ((5)D(0) → (7)F(0), (7)F(1,)(7)F(2), (7)F(3) and (7)F(4)), respectively, with an excitation wavelength of λ(exci) = 392 nm. Among these, the transition (5) D(0) → (7) F(2) (612 nm) displayed bright red emission. In the case of Tb(3+):CaGaSi phosphors, four emission bands were observed at 488 ((5)D(4) → (7)F(6)), 543 ((5)D(4) → (7)F(5)), 584 ((5)D(4) → (7)F(4)) and 614 nm ((5)D(4) → (7) F(3) ) from the measurement of PL spectra with λ(exci) = 376 nm. Among these, the transition (5)D(4) → (7) F(5) at 543 nm displayed bright green emission. The structure and morphology of the phosphors were studied from the measurements of X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX) results.

This paper reports on the spectral results of Sm3+ or Dy3+ ion-doped optical glasses in the following composition: Their X-ray diffraction profiles confirm the amorphous nature of these rare-earth ion-doped glasses. These glasses have shown strong absorption bands in the near-infrared region. The emission spectrum of Sm3+-doped glasses exhibit four emission transitions at 562 nm (4G 5/2→6H 5/2), 598 nm (4G 5/2→6H 7/2), 645 nm (4G 5/2→6H 9/2) and 705 nm (4G 5/2→6H 11/2) with 471 nm (4G 5/2→6I 11/2) as the excitation. Among these, the transition (4G 5/2→6H 7/2) at 598 nm has shown a strong emission. The emission spectrum of Dy3+-doped glass has shown three emission transitions at 482 nm (4F 5/2→6H 15/2), 574 nm (4F 9/2→6H 13/2) and 664 nm (4F 9/2→6H 13/2) with an excitation at 451 nm (6H 15/2→6I 15/2). Upon exposure to UV radiation, Sm3+ and Dy3+ glasses have shown bright reddish-orange and bright yellow colors, respectively, from their surfaces. The emission mechanisms that arise in these glasses have been...

0.25, 0.5, 1.0 and 2.0 mol% of rare earth ions (Eu3+, Tb3+, Sm3+and Dy3+) doped lithium lead boro tellurite glasses have been prepared. From the measured absorption and emission spectra, optical properties have been studied. The absorption spectrum of Eu3+: glass has shown three absorption bands at 394 nm, 465 nm and 533 nm, Tb3+: glass has shown a weak absorption band at 484 nm, Sm3+: glass has shown nine absorption bands at 477 nm, 563 nm, 946 nm, 1081 nm, 1231 nm, 1378 nm, 1482 nm,1525 nm and 1589 nm, Dy3+: glass has shown six absorption bands at 751 nm, 797 nm,900 nm, 1091 nm, 1274 nm and 1680 nm. From Eu3+: glasses, a red emission at 612 nm (5D0 → 7F2) with λexci = 392 nm, Tb3+: glasses, a green emission at 543 nm (5D4 → 7F5) with λexci = 376 nm, Sm3+: glasses, an orange-red emission at 598 nm (4G5/2 → 6H7/2) with λexci = 401 nm and also from Dy3+: glasses, a yellow emission at 574 nm (4F9/2 → 6H13/2) with λexci = 451 nm have been observed. For all these emission bands decay curves have been plotted ...

This article reports on the preparation and optical properties of Sm3+ ions doped B2O3-Bi2O3-ZnO-Li2O (ZLiBiB) glasses. The optical absorption spectra, luminescence spectra and decay curves were measured. On the basis of Judd-Ofelt theory, the intensity parameters Ωλ (λ = 2, 4, 6) and also oscillatory strengths are obtained from the absorption spectra and these results were used to compute the radiative properties of Sm3+: ZLiBiB glasses. Especially the luminescence concentration quenching and the related mechanism were analysed systematically.

An expedient procedure for the acylation of alcohols, phenols, and thiophenols using catalytic amount of Zn(OTf)2 is described. This procedure is highly suitable for industrial application due to use of less toxic metal as a part of catalyst, short reaction time at ambient temperature, without any racemization of chiral alcohols.