Energy transfer based emission analysis of (Tb 3+ , Sm 3+ ): Lithium zinc phosphate glasses (original) (raw)
Related papers
Advances in Materials Physics and Chemistry, 2014
Present paper reports on luminescence characteristics of individually doped Bi 3+ : PZL, Sm 3+ : PZL and co-doped (Bi 3+ /Sm 3+): PZL (50P 2 O 5-30ZnO-20LiF) glasses prepared by a melt quenching method. The results revealed that Bi 3+ : PZL glass exhibited a broad emission peak at 440 nm (3 P 1 → 1 S 0) under excitation wavelength 300 nm (1 S 0 → 3 P 1). Sm 3+ : PZL doped glass has shown a prominent orange emission at 601 nm (4 G 5/2 → 6 H 7/2) with an excitation wavelength 403 nm (6 H 5/2 → 4 F 7/2). Later on Bi 3+ is added to Sm 3+ : PZL glass by increasing its concentrations from 0.1-1.5 mol%. By co-doping Bi 3+ to Sm 3+ : PZL glass, Sm 3+ emission intensity has been considerably enhanced till 1.0 mol% due to energy transfer from Bi 3+ to Sm 3+ and when its concentration exceeds this critical value (1.0 mol%) there has been a drastic decrease in Sm 3+ emission which is explained accordingly from photoluminescence spectra, energy level diagram and lifetime measurements.
Photoluminescence and Energy Transfer Process in Bi3+/Sm3+ Co-Doped Phosphate Zinc Lithium Glasses
Present paper reports on luminescence characteristics of individually doped Bi3+: PZL, Sm3+: PZL and co-doped (Bi3+/Sm3+): PZL (50P2O5-30ZnO-20LiF) glasses prepared by a melt quenching method. The results revealed that Bi3+: PZL glass exhibited a broad emission peak at 440 nm (3P1→1S0) under excitation wavelength 300 nm (1S0→3P1). Sm3+: PZL doped glass has shown a prominent orange emission at 601 nm (4G5/2→6H7/2) with an excitation wavelength 403 nm (6H5/2→4F7/2). Later on Bi3+ is added to Sm3+: PZL glass by increasing its concentrations from 0.1 - 1.5 mol%. By co-doping Bi3+ to Sm3+: PZL glass, Sm3+ emission intensity has been considerably enhanced till 1.0 mol% due to energy transfer from Bi3+ to Sm3+ and when its concentration exceeds this critical value (1.0 mol%) there has been a drastic decrease in Sm3+ emission which is explained accordingly from photoluminescence spectra, energy level diagram and lifetime measurements.
Concentration effect on the spectroscopic behavior of Tb3+ ions in zinc phosphate glasses
Journal of Luminescence, 2015
Zinc phosphate glasses (PZABPTb) in the compositional system: P 2 O 5-ZnO-Al 2 O 3-BaO-PbO) doped with variable Tb 3+ concentrations (1-5 wt% Tb 2 O 3) were prepared and characterized through absorption, excitation, emission and intensity decay rate measurements. The Judd-Ofelt model has been adopted to evaluate the radiative properties of the 5 D 4 7 F 6-3 emission transitions. The effect of Tb 3+ ion concentration on the emissions from the 5 D 3,4 excited levels is discussed in detail. Analysis of the intensity decay curves corresponding to blue and green emissions from levels 5 D 3 and 5 D 4 , respectively, allowed determination of effective lifetimes, which confirmed the Tb 3+ ion concentration quenching of the blue emission in these glasses. The decay curves for the 5 D 3 level are found to be non-exponential in nature for all the studied concentrations due to ion-ion energy transfer through cross-relaxation. In an attempt to identify the origin of the energy transfer mechanism, the decay curves were well fitted to Inokuti-Hirayama model for S = 6, which indicates that the energy transfer process is of dipoledipole type. The optical band gap energy (E opt) has been evaluated taking into account the ultraviolet edge of absorption spectra.
Li 2 O–BaO–Al 2 O 3 –La 2 O 3 –P 2 O 5 glasses optically activated with rare earth ions with the 4f 5 , and 4f 8 electronic configuration (Sm 3+ and Tb 3+ , respectively) were analyzed by Raman spectroscopy, absorption, excitation photoluminescence, decay curves and temperature dependent photoluminescence. The spec-troscopic characteristics of the as-prepared and heat treated samples at temperatures below and above T g were studied as well as their room temperature photometric properties under ultraviolet excitation. All the doped glasses exhibit typical signatures of the lanthanides in their trivalent charge state. For the samarium doped glass heat treated at 250 °C (<T g) the Sm 2+ luminescence was also observed. The analysis of the luminescence efficiency was performed in the interval range of 14 K to room temperature, where the integrated intensity of the luminescence was found to decrease for the Sm 3+ and Tb 3+ ions in the studied temperature range. Luminescence decay curves were found to be non-exponential for the 4 G 5/2 ? 6 H 7/2 and 5 D 3 ? 7 F 4 transitions of the Sm 3+ and Tb 3+ ions, respectively. The results strongly suggest the occurrence of energy transfer processes through cross relaxation phenomena, mediated by dipole–dipole interaction in all the studied samples. The decay of the 5 D 4 ? 7 F 5 emission of the Tb 3+ ions was found to be single exponential with a time constant of $3.1 ms. Based on the spectroscopic characteristics, models for recombination processes are proposed. The room temperature luminance photometric properties with ultraviolet excitation show that the samarium doped glasses have much lower luminance intensity (around 0.3 Cd/m 2) when compared with the 6–7 Cd/m 2 observed for the terbium doped ones.
Journal of Luminescence, 2015
The fluorescence properties of different concentrations of Sm 3 þ doped zinc-aluminum-sodium-phosphate (ZANP) glasses were studied by the XRD, SEM, FTIR, TG-DTA, optical absorption, photoluminescence and decay cure analysis. X-ray diffraction profiles and SEM images confirmed the amorphous nature of the glass samples. Structural information of these glass matrices was provided by FTIR spectrum. Judd-Ofelt (J-O) theory was applied to the experimental oscillator strengths to evaluate three phenomenological J-O intensity parameters, Ω λ (λ¼ 2, 4 and 6). Using J-O intensity parameters and emission spectra, various radiative parameters such as radiative transition probabilities (A R ), radiative lifetimes (τ R ), calculated and measured branching ratios (β R and β m ), effective bandwidths (Δλ eff ) and stimulated emission cross-sections (σ P ) were calculated for observed emission transitions. The intensity of emission transitions with the variation of Sm 3 þ ion concentration was studied. The nature of decay curves of 4 G 5/2 level for different Sm 3 þ ion concentrations in ZANP glass was analyzed and obtained measured lifetimes (τ exp ). Quantum efficiency of 4 G 5/2 level was calculated based on experimental and measured radiative lifetimes (τ exp and τ R ).
Energy transfer in Sm 3+:Eu 3+ system in zinc sodium phosphate glasses
Optical Materials, 2004
The mechanism of nonradiative energy transfer process in zinc sodium phosphate glass system co-doped with samarium and europium ion has been examined under cw laser excitation. Donor-acceptor distance and quantum efficiency of transfer have been evaluated using the relevant theoretical expressions. Transfer probabilities have been determined using the overlap integral and relative fluorescence methods. The Forster-Dexter theoretical predictions are found to be in excellent agreement with experimental results. The nonresonant energy transfer assisted by phonons is the dominant transfer mechanism in the concentration range taken. Excitation spectra and the decay profile of the samarium ion also support the energy transfer from samarium to europium.
Process in Bi3+/Sm3+ Co-Doped Phosphate Zinc Lithium Glasses
and co-doped (Bi3+/Sm3+): PZL (50P2O5-30ZnO-20LiF) glasses prepared by a melt quenching method. The results revealed that Bi3+: PZL glass exhibited a broad emission peak at 440 nm (3P1→1S0) under excitation wavelength 300 nm (1S0→3P1). Sm3+: PZL doped glass has shown a prominent orange emission at 601 nm (4G5/2→6H7/2) with an excitation wavelength 403 nm (6H5/2→4F7/2). Later on Bi3+ is added to Sm3+: PZL glass by increasing its concentrations from 0.1 -1.5 mol%. By co-doping Bi3+ to Sm3+: PZL glass, Sm3+ emission intensity has been considerably enhanced till 1.0 mol% due to energy transfer from Bi3+ to Sm3+ and when its concentration exceeds this critical value (1.0 mol%) there has been a drastic decrease in Sm3+ emission which is explained accordingly from photoluminescence spectra, energy level diagram and lifetime measurements.
Concentration dependent luminescence properties of Sm3+-ions in tellurite–tungsten–zirconium glasses
Optical Materials, 2015
Dysprosium (Dy 3?) doped lead free zinc phosphate glasses with chemical compositions (60x) NH 4 H 2 PO 4 ? 20ZnO ? 10BaF 2 ? 10NaF ? xDy 2 O 3 (where x = 0.5, 1.0, 1.5, 2.0 mol%) have been prepared by melt quenching technique. The functional groups of vibrational bands have been assigned and clearly elucidated by FTIR and Raman spectral profiles for all these glass samples. Judd-Ofelt (J-O) intensity parameters (X k : k = 2, 4, 6) have been obtained from spectral intensities of different absorption bands of Dy 3? doped glasses. Radiative properties such as radiative transition probabilities (A R), radiative lifetimes (s R), branching ratios (b R) and integrated absorption crosssections (R) for different excited states are calculated by using J-O parameters. Luminescence spectra exhibit three emission bands (from 4 F 9/2 level to 6 H 15/2 , 6 H 13/2 and 6 H 11/2) for all the concentrations of Dy 3? ions before and after gamma irradiation. Various luminescence properties have been studied by varying the Dy 3? concentration for the three spectral profiles. Fluorescence decay curves of 4 F 9/2 level have been recorded. The energy transfer mechanism that leads to quenching of 4 F 9/2 state lifetime has been discussed by the variation of Dy 3? concentration. These glasses are expected to be useful for yellow luminescent materials.
Tb 3+ and Eu 3+ doped zinc phosphate glasses for solid state lighting applications
Tb 3+ and Eu 3+ doped zinc phosphate (ZP) glasses were prepared by conventional melt-quenching technique and their photoluminescence properties were investigated in detail. For, Tb 3+ doped glasses the intense emission was at 545 nm corresponding to 5 D 4 → 7 F 5 transition under 377 nm n-UV excitation. The optimized concentration for Tb 3+ doped zinc phosphate glass was 3 mol% and above this concentration quenching takes place. The Eu 3+ doped zinc phosphate glass revealed intense emission at 613 nm attributed to the 5 D 0 → 7 F 2 transition under intense 392 nm n-UV excitation. The concentration quenching phenomenon was not observed in the Eu 3+ doped ZP glasses. The CIE chromaticity coordinates for 3 mol% Tb 3+ and 5 mol% Eu 3+ doped ZP glasses were found to (0.283, 0.615) and (0.652, 0.331) lying in the green and red regions, respectively. The above mentioned results indicate that the prepared glass are suitable for application in the field of lighting and display devices.
Spectroscopic and radiative properties of Sm3+- doped phosphate glasses
Sm 3 þ -doped K-Mg-Al phosphate glasses were prepared and characterized through various spectroscopic techniques such as optical absorption, excitation, photoluminescence spectra and decay rate analysis at room temperature to derive spectroscopic and radiative properties of Sm 3 þ ions in these glasses. Energy parameters for the 4f 5 electronic configuration of Sm 3 þ ion in K-Mg-Al phosphate glass have been determined using free-ion Hamiltonian model. Judd-Ofelt (JO) analysis has been applied to evaluate the JO intensity parameters, O l (l¼ 2, 4 and 6), and in turn radiative properties such as radiative transition probability, branching ratio, radiative lifetime and peak stimulated emission crosssection for the fluorescent 4 G 5/2 level of Sm 3 þ ion have been determined. The fluorescence decay rates exhibit single exponential at lower concentrations (r 0.1 mol%) and turn into non-exponential at higher concentrations (Z 0.5 mol%). The experimental lifetime for the 4 G 5/2 level as a function of Sm 3 þ ions concentration decreases from 2.77 to 0.74 ms when the concentration is increased from 0.05 to 2.0 mol% of Sm 2 O 3 due to energy transfer process. The non-exponential decay rates are well-fitted to Inokuti-Hirayama model for S ¼ 6 indicating that the nature of the energy transfer process is of dipoledipole type. The systematic analysis on decay rates indicates that the energy transfer mechanism depends on Sm 3 þ ion concentration as well as glass composition.