Spectroscopic and fluorescence properties of Sm~(3+)-doped zincfluorophosphate glasses

Optical absorption and fluorescence spectra of Sm3＋-doped zincfluorophosphate glasses with molar composition of 44P2O5＋17K20＋9Al2O3＋（30-χ）ZnF2＋χSm2O3 （χ=0.01 mol.%, 0.05 mol.%, 0.1 mol.%, 0.5 mol.%, 1.0 mol.%, 2.0 and 3.0 mol.%） referred as PKAZFSm were prepared by melt quenching technique and were characterized through Raman, absorption, emission and decay curve analysis. From the absorption spectra, Judd-Ofelt intensity parameters were determined and were used to predict radiative properties such as transition probabilities （AR, radiative lifetimes （τR）, branching ratios （βR）, effective bandwidths （△λeff） and stimulated emission cross-section （σ（λp）） for the excited 4G5/2 luminescent level. The decay curve for the 4G5/2 level was single exponential for lower concentration and became non-exponential for higher concentrations. The non-exponential nature of the decay curves of the 4G5/2 level increased with increase in Sm3＋ ions concentration accompanied by decrease in lifetime due to energy transfer processes among the Sm3＋ ions. The non-exponential decay curves was well fitted to the generalized Inokuti-Hirayama model for S=6, indicating that the energy transfer among optically active ions was of dipole-dipole interaction. The cross-relaxation mechanism responsible for the quenching of lifetimes and the effect of variation of concentration on the spectroscopic properties were also discussed.     

Spectral properties and energy transfer of Tm~(3 )/Ho~(3 )-codoped Ga_2O_3-Bi_2O_3-GeO_2-PbO glasses

The 2.0 μm emission originating from Ho3 :5I7→5I8 transition in Ho3 /Tm3 -codoped gallate-bismuth-germanium-lead glasses were investigated upon excitation with 808 nm laser diode (LD). Energy transfer (ET) process between Tm3 : 3F4 level and Ho3 : 5I7 level was also discussed. It was noted that the measured peak wavelength and stimulated emission cross-section of Ho3 -doped bis-muth-germanium-lead glasses were ～2.02 μm and 5.1×10–21 cm2, respectively. Intense emission of Ho3 in Tm3 /Ho3 -codoped GBPG glass were observed, which resulted from the ET between Tm3 : 3F4 and Ho3 : 5I7 level upon excitation with 808 nm LD.     

Electrochemical response of Nd~(3+) ions containing lithium borate glasses

The present investigation was to understand the electrical properties of 27.5 Li_2O-(72.5–x) B_2O_(3-x)Nd_2O_3 with x=0.5, 1, 1.5 and 2 glasses. We analyzed the impedance data for a wide frequency range to get inside the conduction phenomenon. The conductivity of the glasses decreased due to the decrease in the mobility of mobile Li~+ ions. This decrease was due to polymerization of glass network caused by the Nd~(3+) ions. Modulus formalism confirmed that the Li~+ ions overcame the same barrier no matter whether it took part in the conduction process or relaxation process. Scaling of the electrochemical data showed that conduction process in the ion conducting glasses was composition dependent and not the temperature dependent.     

Optical properties of Eu2+-doped strontium borate glasses containing F- and Li+ ions

In this experiment, strontium borate glasses were prepared using the conventional quenching method in air atmosphere. Optical absorption, photoluminescence excitation and emission spectra, X-ray excited luminescence (XEL), and luminescence decay curve of the as-prepared glasses were investigated at room temperature. The as-prepared glasses had two kinds of Eu ions, i.e., Eu2 and Eu3 . Compared with the reported results of strontium borate glasses, Eu2 luminescence was enhanced in the studied strontium borate glasses coprepared with F- and Li ions. The coexisting of Li or F- in the borate glasses could create more negative defect VSr″ and stabilize Eu2 ions, which might act as donor of electrons;For the F- doping, the new center of B(O, F)4 (or BO3F) and BO2F2 units could be considered to be the distorted (BO4), which were needed as a rigid framework to stabilize the divalent rare earth ions.     

Spectral properties and energy transfer of Tm^3＋/Ho^3＋-codoped Ga2O3-Bi2O3-GeO2-PbO glasses

The 2.0 μm emission originating from Ho^3＋：^5I7→^5I8 were investigated upon excitation with 808 nm laser diode （LD） transition in Ho^3＋/Tm^3＋-codoped gallate-bismuth-germanium-lead glasses Energy transfer （ET） process between Tm^3＋： ^3F4 level and Ho^3＋： ^5I7 level was also discussed. It was noted that the measured peak wavelength and stimulated emission cross-section of Ho^3＋-doped bismuth-germanium-lead glasses were -2.02 μm and 5.1×10^-21 cm^2, respectively. Intense emission of Ho^3＋ in Tm^3＋/Ho^3＋-codoped GBPG glass were observed, which resulted from the ET between Tm^3＋： ^3F4 and Ho^3＋： ^5I7 level upon excitation with 808 nm LD.     

Electrical and optical properties of lithium borate glasses doped with Nd2O3

Glass series with general formula 25Li2O-(75-x)B2O3-xNd2O3 was prepared by conventional melt quench technique. Electrical and optical characterizations of these glasses were carried out. It was observed that conductivity of glasses decreased and activation energy increased with the addition of Nd2O3. The density and refractive index of the glasses increased while optical band gap and radiation length decreased due to structural changes.     

Spectroscopic Properties of Nd^3＋-Doped Tellurite Glasses

Spectroscopic Properties of Nd~(3 )-Doped Tellurite Glasses     

Spectral properties and energy transfer of Tm3+/Ho3+-codoped Ca2O3-Bi2O3-GeO2-PbO glasse

The 2.0 μm emission originating from Ho3+:5I7→5I8 transition in Ho3+/Tm3+-codoped gallate-bismuth-germanium-lead glasses →5I8 transition in Ho3+/Tm3+-codoped gallate-bismuth-germanium-lead glasses were investigated upon excitation with 808 nm laser diode (LD). Energy transfer (ET) process between Tm3+: 3I4 level and Ho3+: 5I7 level nergy transfer (ET) process between Tm3+: 3I4 level and Ho3+: 5I7 level was also discussed. It was noted that the measured peak wavelength and stimulated emission cross-section of Ho3+-doped bis-It was noted that the measured peak wavelength and stimulated emission cross-section of Ho3+-doped bis-muth-germanium-lead glasses were ～2.02 μm and 5.1×10-21 cm2, respectively. Intense emission of Ho3+ in Tm3+/Ho3+-codoped GBPG glass ×10-21 cm2, respectively. Intense emission of Ho3+ in Tm3+/Ho3+-codoped GBPG glass were observed, which resulted from the ET between Tm3+: 3I4 and Ho3+: 5I7 level upon excitation with 808 nm LD. the ET between Tm3+: 3I4 and Ho3+: 5I7 level upon excitation with 808 nm LD.     

Luminescence properties of Tm^3＋/Yb^3＋, Er^3＋/Yb^3＋ and Ho^3＋/Yb^3＋ activated calcium tungstate

CaWO4 phosphor activated by the Tm3+/Yb3+,Er3+/Yb3+ and Ho3+/Yb3+ ions were synthesized by a traditional high-temperature solid-state method.The crystal structures and morphologies of the products were characterized by X-ray powders diffraction method(XRD) ,infrared spectra(FT-IR) and scanning electron microscopy(SEM) .The samples were found to show up-conversion luminescence properties.CaWO4 doped with Tm3+/Yb3+ showed blue luminescence characteristic of Tm(III) ion in the range of 460-485 nm,corresponding to the 1G4→3H6 electronic transition.CaWO4 doped with Er3+/Yb3+ showed strong green luminescence at 510-565 nm(2H11/2,4S3/2→4I15/2) and weak red luminescence at 640-685 nm(4F9/2→4I15/2) of Er(III) ion.CaWO4 doped with Ho3+/Yb3+ phosphor emitted green luminescence at 525-560 nm(5S2,5F4→5I8) and red luminescence at 630-670 nm(5F5→5I8) and at 730-770 nm(5S2,5F4→5I7) ,which is the characteristic of Ho(III) ion.     

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 ?) 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(σE P), 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.     

Dependence of the emission electric dipole line strength of Eu~(3+) on the composition of lead borate glasses

Lead borate glasses xB2O3+(99-x)PbO+0.5Eu2O3(x=70,60,...,10) were prepared by melt-quenching method.The luminescent properties were characterized with excitation and emission spectra.The emission intensities for 5D0-7FJ(J=0-4) were analyzed to give variation of the relative electric dipole line strengths with the composition of glasses so as to examine the crucial implicit assumption of independent electric dipole line strength on the composition of glass in the Phys.Rev.Lett.2003,91,203903 paper studying l...     

Up-conversion luminescence from Nd~(3+) ions doped in NaBi(WO_4)_2 single crystal

The luminescence of Nd3+-doped in NaBi(WO4)2 single crystal was investigated from 10 K to room temperature.The excitation source was a pulsed dye laser in resonance into the(4G5/2+2G(1)7/2) levels of Nd3+ ions.Several blue emission bands in the up-conversion luminescence spectra corresponded to transitions from 2P1/2 to 4I9/2.Some violet bands corresponding to transitions of 4D3/2→(4I9/2,4I11/2,4I13/2) were also observed.For comparison,the luminescence spectra and decay curves excited by the pulsed 355 nm l...     

Investigation on Upconversion Luminescence of Tm^3＋/Yb^3＋-Codoped Oxychloride Tellurite Glasses

Investigation on Upconversion Luminescence of Tm~(3 )/Yb~(3 )-Codoped Oxychloride Tellurite Glasses     

Investigation on 1.07 μm laser emission in Nd~（3＋）-doped sodium fluoroborate glasses

Spectroscopic and fluorescence properties of Nd 3+ ions in sodium fluoroborate(SFB) glasses were prepared and characterized through optical absorption,emission and decay measurements.The energy level analysis was carried out using free-ion Hamiltonian model.Experimental oscillator strengths were determined by measuring the area encompassed by the absorption peaks recorded for 1.0 mol.% Nd 3+-doped glasses.The Judd-Ofelt parameters(2,4,6) were used to evaluate the laser characteristic parameters such as radiative transition probability(A R),radiative decay time(τ R),fluorescence branching ratio(β R) and stimulated emission cross-section(σ e) for the 4 F 3/2 metastable state.The fluorescence spectra for different concentrations of Nd 3+ ions were recorded by exciting the samples at 514.5 nm Ar + ion laser.     

Influence of CeO2 on scintillating properties of Tb3+-doped silicate glasses

A series of Tb3+-,Ce3+-doped,and Tb3+/Ce3+-codoped silicate glasses were synthesized by melt-quenching technique.Some properties of the investigated glasses were characterized by X-ray photoelectron spectroscopy(XPS),photoluminescence(PL),X-ray excited luminescence(XEL) and thermoluminescence(TL) spectra.The result of XPS revealed that both Ce3+ and Ce4+ ions coexisted in these silicate glasses,and energy transfer from Ce3+ to Tb3+ ions was observed under UV excitation.However,under X-ray excitation the XEL...     

Spectroscopic Properties and Effect of Radiation Trapping of a New Er^3＋/Yb^3＋ Co-Doped Tellurite-Silicate Glasses

A new serials of Er^3＋/Yb^3＋ co-doped tellurite-silicate glasses were prepared by the technique of high-temperature mehing. The thermal stability, absorption spectra, emission spectra and upconversion spectra were measured and investigated. It is found that these kinds of glasses have good thermal stability, broad FWHM and large stimulated emission cross-section. The three upconversion emission at 525, 546, 658 nm, corresponding to the ^2H11/2→^4Ⅰ15/2, ^4S3/2→4^Ⅰ15/2 and ^F9/2→^4Ⅰ15/2 transitions of Dr^3＋ ions,     

Effect of yttrium oxide addition on absorption and emission properties of bismuth-doped silicate glasses

Y/Bi co-doped silicate glasses were prepared,and the effects of Y 2 O 3 on the absorption and emission properties were investigated by spectrum measurement.It was found that the absorption intensity in visible region decreases with increase of Y 3+ concentration in(70-x)SiO 2 xY 2 O 3-30CaO-1.5Bi 2 O 3(x=0 mol.%,1 mol.%,3 mol.%,5 mol.%,7 mol.%) glasses.The emissions centered at 410,630,1200 and 1290 nm were observed under 280,470,514 and 808 nm excitation,respectively.The emission intensity had the similar change tendency in the visible and near infrared region.We also discussed the actual role of Y 3+ ions playing in the visible and near infrared emissions of the silicate glasses.     

Luminescent properties and energy transfer of color-tunable Sr3Y2（SiO3）6：Ce3＋,Tb3＋ phosphors

Phosphors with controlled emission spectra are of great interest due to their application for white light emitting diodes.Herein, a new class of Sr3Y2（SiO3）6：Ce3＋,Tb3＋ phosphors were synthesized by a facile sol-gel combustion method. The phase structure,morphology, and luminescence properties of the phosphors were characterized by using powder X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, and photoluminescence excitation and emission spectra,respectively. The results on luminescence properties indicated that co-doped Ce3＋ ions served as UV-light sensitizers with excitation energy partially transferred to Tb3＋ ions, leading to green emission from Tb3＋. Particularly, the corresponding emitting colors of the phosphors could be well-tuned from deep blue（0.16, 0.05） to green region（0.25, 0.45） by adjusting the molar ratio of Ce3＋/Tb3＋.     

Enhanced photoluminescence properties of （Y,Bi） BO_3：RE~（3＋） （RE=Eu,Tb） phosphors synthesized at low temperature

Eu3+ or Tb3+ doped Y(1-x)BixBO3 (0.1≤x≤0.4) phosphors were synthesized using the simple solid state method at low temperature from 700 to 870 ℃. The analysis of the X-ray diffraction (XRD) indicated that the system of Y(1-x)BixBO3 (0.1≤x≤0.4) had the same structure as that of YBO3. The excitation spectra, emission spectra and decay lifetimes of all samples were measured in detail. All the samples exhibited characteristic luminescence of Eu3+ or Tb3+. Y0.65Bi0.2Eu0.15BO3 and Y0.8Bi0.1Tb0.1BO3 samples had the...     

Spectroscopic and structural properties of MgAl_2O_4:Nd~(3+) nanopowders and ceramics

The structural and spectroscopic properties of MgAl2O4:1%Nd3+ spinel nanocrystals and ceramics were measured and analyzed. Ceramics were prepared from the above mentioned spinel nanocrystals and undoped commercial spinel powder, using the spark plasma sintering(SPS) method. Properties of the obtained ceramics strongly depended on the SPS conditions. The samples were not homogeneous and possessed defects and pores. The most transparent ceramics had 60% transparency at 1000 nm.