Series Of Tb3 Research Articles

[formula omitted] leaves mediated combustion synthesis of Tb[formula omitted] doped Zn2V2O7 nanoparticles: Color tunable photoluminescence and electrochemical studies for display and supercapacitor applications

A new series of Tb3+ doped Zn2V2O7 (ZV) nanoparticles (NPs) at different concentration from 1 to 9 mol% was synthesized by Menthaspicata leaves extract mediated solution combustion method. On Tb3+ doping, the diffraction pattern matches well with the monoclinic crystal structure with the C2/c(2/m) space group of ZV host matrix. The surface morphology tuned from irregular shaped NPs to hexagonal shaped NPs with variation in dopant concentration. The crystallite size estimated from Scherrer’s method matches well with the transmission electron microscopy analysis. The optical band gap determined from Tauc’s plot utilizing UV–Visible absorption was tuned from 3.061 to 3.035 eV with increase in dopant concentration. Under 266 nm excitation, the emission of Tb3+ ions from Tb3+-doped ZV NPs is observed, with the intensity of emission showing sensitivity to the concentration of Tb3+ ions. The optimal doping content is determined to be 7 mol %. The CIE coordinates clearly indicates the tuning of the emission color from green to blue region with increase in dopant concentration. The average color coordinated temperature was found to be 7895 K showing the cooler appearance. Further, cyclic voltammetry analysis offers valuable insights into redox reactions, electrode kinetics, and overall electrochemical behavior, while Electrochemical Impedance Spectroscopy (EIS) provides information on ion transport kinetics. Galvanostatic Charge–Discharge (GCD) analysis revealed supercapacitance values ranging from 79.43 to 133.26 F/g at 10 mV/s with increasing dopant concentration. These findings underscore the potential of this material for use in energy storage and display technology applications.

Color-tunability and energy transfer of a highly thermal-stable BaZnB4O8:Tb3+/Eu3+ phosphor for single-component w-LEDs

A series of Tb3+ single-doped and Tb3+/Eu3+ co-doped BaZnB4O8 samples with color tuning were efficiently synthesized using the solid-state reaction method. The crystal structure, photoluminescence and the energy transfer process (ET) of the samples were systematically studied. The optimal BaZnB4O8:0.08Tb3+ sample shows efficient green emission, then tunable color was achieved by merely introducing a few of Eu3+ ions owing to the highly efficient ET process from Tb3+ to Eu3+ in the BaZnB4O8:0.08Tb3+/yEu3+ samples. The ET efficiency from Tb3+ to Eu3+ of the BaZnB4O8:0.08Tb3+, yEu3+ samples rose from 32.1 % to 51.6 %, simultaneously the luminescent quantum yield improved from 24.7 % to 36.8 %, as the Eu3+ doping concentration increased from 0.125 % to 2 %. Moreover, the Tb3+/Eu3+ co-doped samples exhibited great thermal stability, keeping about 90.2 % (@150 °C) of their original intensity at room temperature. Finally, white light was achieved by a warm w-LEDs fabricated by coating the BaZnB4O8:0.08Tb3+, 0.0025Eu3+ sample on a 365 nm chip. The w-LEDs showed outstanding performance characteristics, with a CCT of 3869 K and a CRI of 89.3. According to the results, Tb3+/Eu3+ co-doped BaZnB4O8 samples have the potential to serve as single-component multicolor-emitting or white-emitting phosphors upon excitation at near-UV wavelength.

Lattice distortion effects induced by Li+ co-doping on ZnO:Tb3+ phosphors: Photoluminescence and unusual hypersensitive ⁵D₄ → ⁷F₀ transition

A series of Tb3+, Li+ co-doped ZnO phosphors were prepared using a precipitation method. X-ray diffraction (XRD) analysis indicated the successful incorporation of Tb3+ into the ZnO lattice. The influence of Tb3+ doping content and Li+ charge compensator on the photoluminescence (PL) properties of ZnO:Tb3+ was investigated. Under UV excitation, emissions corresponding to electron transitions 5D4→7FJ (J = 0,1,2,3,4,5,6) were observed from Tb3+ ions, including an unusual emission transition at 673 nm, which significantly enriches our understanding of Tb3+ luminescence. The critical concentration quenching of Tb3+ in ZnO:Tb3+ occurs at 7 mol%, as explained by the Van Uitert equation, which attributes this phenomenon to dipole-dipole interactions. Surprisingly, incorporating Li+ for charge balancing led to a reduction in the luminescence intensity of ZnO:7 mol%Tb3+, x%Li+ phosphors (x = 0.01 and 0.07) at 544 nm. This reduction highlights an increased degree of lattice distortion due to Li⁺ inclusion. Furthermore, CIE chromaticity analysis showed that the optimal doping concentration of 0.07 Tb³⁺ shifted the color coordinates towards vivid green, with a color temperature of approximately 6241 K, indicating of neutral white light.

Luminescence properties and Judd-Ofelt analysis of Tb3+ doped Sr2YTaO6 double perovskite phosphors for white LED applications.

A series of Tb3+-doped Sr2YTaO6 double perovskite phosphors (SYT:Tb3+) were synthesized using a conventional solid-state reaction method. A strong green emission was observed in the SYT:Tb3+ phosphors, and the optimal doping concentration of Tb3+ was confirmed to be 5 mol%. The electric dipole-dipole interaction was ascribed to be the main mechanism for the luminescence concentration quenching. Analysis of the concentration-dependent fluorescence decay confirmed that the self-generated quenching model holds for the dynamic process of Tb3+ decays in SYT. Furthermore, the internal quantum efficiencies, non-radiative transition rates, and energy transfer rates of the 5D4 level for the SYT:Tb3+ samples were estimated, respectively. The luminescence thermal stability of the sample was also evaluated based on the Arrhenius model. The chromaticity shift of the SYT:5 mol% Tb3+ phosphor was examined to be 0.013 when the sample temperature was increased from 303 to 483 K, thus indicating excellent chromaticity shifting resistance under high temperature conditions. Moreover, the Judd-Ofelt parameters were calculated from the emission spectra of SYT:Tb3+ to be Ω2 = 0.29 × 10-20, Ω4 = 0.45 × 10-20, and Ω6 = 0.72 × 10-20 cm2, respectively. The fluorescence branching ratios and radiative transition rates for the 5D4 level were calculated based on the obtained Judd-Ofelt parameters. Finally, a white light-emitting diode (LED) prototype was assembled using a 310 nm LED chip combined with a prepared green SYT:Tb3+ phosphor and two other commercial blue and red phosphors. The obtained warm white light exhibits good chromaticity coordinates (0.32, 0.32) and a high color rendering index of 96.1. Based on the above results, it can be known that the prepared SYT:Tb3+ phosphors have a potential application as green emitting phosphors in white LEDs.

Molten salt synthesized Tb3+, Pr3+ or Dy3+ single doped CaTa4O11 with persistent luminescence.

A series of Tb3+, Pr3+ and Dy3+ monodoped CaTa4O11(CTO) persistent luminescence (PersL) phosphors have been successfully synthesized using the molten salt method with KCl flux. The PersL color is green and orange for Tb3+ and Pr3+ or Dy3+ doped samples, respectively. The trap depth of Tb3+, Pr3+ and Dy3+ monodoped CTO is 0.33, 0.31 and 0.30 eV, respectively. The PersL time of 3 mol% Tb3+, 1 mol% Pr3+ and 1 mol% Dy3+ monodoped samples is 52.20, 35.00 and 59.46 s, respectively. Tb3+, Pr3+ and Dy3+ monodoped CTO phosphors can be used in luminescence displays and anti-counterfeit labels under commercial 254 nm UV light.

Tb3+–Yb3+ doped glass ceramics containing NaBi(MoO4)2: preparation and upconversion luminescence

A series of Tb3+–Yb3+co-doped transparent glass ceramics (GCs) containing NaBi(MoO4)2 were synthesized.

The Sr(La1-xTbx)AlO4 (x= 0–1) type layered perovskite: Full substitution of La site, restrained photoluminescence concentration quenching, and novel long afterglow luminescence

A series of Tb3+ substituted layered perovskite Sr(La1-xTbx)AlO4 (x = 0–1) was synthesized via solid-state reaction. The influence of Tb3+ on the phase, structure, photoluminescence, and long afterglow properties of the SrLaAlO4 product was investigated. The fully substituted product SrTbAlO4 was found to be isostructural with its SrLaAlO4 counterpart, and the crystal structure parameters were first reported in this work. Photoluminescence investigation found that benefiting from the unique layered crystal structure, the activator Tb3+ was well separated and the optimal doping concentration was found to be as high as 20 at%. Except for photoluminescence, the products simultaneously show long afterglow properties due to disorder cations distribution in the local structure and thus induced defect condition. When the UV light source is turned off, the afterglow luminescence of SrLaAlO4: 0.03 Tb3+ can last over 1 h. The trap distribution of SrLaAlO4: Tb3+ was analyzed in detail by thermoluminescence. The trap depth is calculated to be around 0.7–0.81 eV, the value of which highly coincides with the ideal energy level for trapping and releasing electrons at room temperature. On the basis of the experimental results, the mechanism of long afterglow luminescence of SrLaAlO4: Tb3+ is elaborated and discussed.

Preparation and Spectral Properties of MgAl2O4: Tb3+ Phosphor

A series of Tb3+ doped cubic MgAl2O4 green phosphors were synthesized via hydrothermal method followed by a post-annealing process. The variation regularity of phase structure, morphology, particle size and concentration quenching mechanism were investigated. The results showed that the crystal structure of matrix materials was not affected when Tb3+ ions were introduced. In addition, the micrometer-sized rods and excellent dispersion of the particles were obtained by adding urea. Under excitation at 377 nm, the phosphors exhibited the characteristic of Tb3+ emissions with the peaks located at 488 nm (5D4 → 7F6), 544 nm (5D4 → 7F5) and 588 nm (5D4 → 7F4), respectively. Moreover, based on optical analysis, it can be inferred that electric dipole-dipole (d-d) interaction plays an important role in concentration quenching process of Tb3+ ions. The green light emitting phosphor MgAl2O4: Tb3+ can be realized by adjusting the concentrations of Tb3+, and the optimum concentration of Tb3+ ions in MgAl2O4 was found to be 0.02. Finally, the average fluorescence decay lifetime and the CIE chromaticity coordinates of Mg0.98Al2O4: 0.02Tb3+ phosphor were calculated to be 1.2005 ms and (0.3197 0.4109), respectively. The above results suggest that the developed phosphor could have potential to be used as a single-phase green emission phosphor for near-ultraviolet light-emitting diode (NUV-LED) applications.

Designing multicolor luminescence in Tb3+/Eu3+-codoped KGd2F7 nanoparticles through energy transfer engineering for warm white light-emitting diode

By a facile precipitation method at room temperature, series of Tb3+-doped and Tb3+/Eu3+-codoped KGd2F7 nanoparticles (NPs) were synthesized. Upon 377 nm excitation, Tb3+-doped KGd2F7 NPs possess intense green emissions and their strongest intensities are obtained when Tb3+ ion is 30 mol%, where the corresponding concentration quenching mechanism is electric dipole-quadrupole interaction. As for Tb3+/Eu3+-codoped KGd2F7 NPs, dazzling multi-color emissions are achieved, excited by 377 nm, triggered by the energy transfer (ET) from Tb3+ to Eu3+. Specially, the emitting color is changed from green to yellow and finally to red as Eu3+ content increases. Through systematical discussion based on the emission spectra and decay time, the ET mechanism is decided by dipole-dipole interaction. Moreover, Tb3+/Eu3+-codoped KGd2F7 NPs do not only have high thermal stability but also exhibit admirable quantum efficiency of 65.7% excited by 377 nm. Furthermore, through utilizing the resultant NPs as yellow-emitting components, a warm white light-emitting diode with high color rendering index (85.5) and low correlated color temperature (4323 K) is fabricated, which are insensitive to injection current. Our findings may provide promising luminescence materials with multicolor emissions to meet the requirement of phosphor-converted solid-state lighting.

Energy transfer of Tb3+→Eu3+ in Ca2Al2SiO7 phosphors with multicolor tunable and optical temperature sensing properties

Luminescent temperature sensors based on photoluminescent materials have received considerable attention for their advantages of quick and noninvasive measurement. In this paper, a series of Tb3+, Eu3+ single-doped and co-doped Ca2Al2SiO7 (CAS) phosphors were synthesized by sol-gel method. The phase purity, surface morphology, energy transfer, luminescence characteristics and temperature sensing properties of Tb3+, Eu3+ doped CAS phosphors have been studied carefully. Due to the energy transfer of Tb3+→Eu3+, CAS: Tb3+, Eu3+ phosphors demonstrate tunable luminescence under 238 nm excitation, in which the luminescence color gradually changes from purple-red to cool white, and then to warm white by continuously increasing the concentration of Tb3+ ions. The elongation of the fluorescence lifetime of Eu3+ with increasing Tb3+ ions content further confirms the energy transfer of Tb3+→Eu3+. The thermal behavior of CAS: Tb3+, Eu3+ phosphors shows enhanced luminescence intensity for 404 nm emission while suppressed luminescence intensity for 616 nm emissions with raising temperature, implying its potential in optical temperature sensing. Therefore, the temperature sensing performance is evaluated by using the fluorescence intensity ratio (I404 nm /I616 nm) in CAS: Tb3+, Eu3+ phosphors, showing a maximum relative sensitivity of 1.17%K−1 at 443 K. These results indicate that CAS: Tb3+, Eu3+ phosphors are promising candidates for tunable luminescence and non-contact temperature sensing.

Photoluminescence of Tb3+/Sm3+ ions co-activated in SrO - Na2O - WO3 - tellurite glasses for multicolor laser applications

A novel series of Tb3+, Sm3+ single doped and Tb3+/Sm3+ co-incorporated tungsten tellurite glasses were synthesized by melt quenching technique and corresponding structural as well as luminescence features of the prepared glasses have been reported here. Spectral overlapping between the luminescence spectra of Tb3+ ions and the excitation spectra of Sm3+ ions manifests that the energy transfer process takes place from Tb3+ ions to Sm3+ ions. By using the dual excitations at 377 and 484 nm, the titled co-doped glasses emit green light of wavelength 542 nm along with reddish – orange colour light at 599 nm. In addition to this, there is no possibility of reverse energy transfer which is validated with the help of excitation at 403 nm (Sm3+ ions) as major evidence. The lifetimes of all co-doped glasses decline with increasing Tb3+ doping level in the ligand matrices, indicating the energy migration process takes place from Tb3+→ Sm3+. The chromaticity coordinates of all synthesized co-doped glasses lie in yellowish-orange region of CIE1931 diagram and it shifts to deep yellow region when Tb3+ ion concentration varies. Our findings propose that the titled glasses can be used as visible laser materials for multicolor laser applications.

Enhancement on Tb3+ luminescence in CaScBO4-based ceramic phosphors by Ce3+-induced resonance energy transfer and the generation of white light emission collaborated with Mn2+

A series of Tb3+-doped, Ce3+,Tb3+-co-doped and Ce3+,Tb3+,Mn2+-tri-doped CaScBO4 (CSB) ceramic phosphors were prepared by solid-state reaction. X-ray diffraction (XRD) was taken to confirm the phase purity of all as-prepared phosphors powder. Steady-state and transient-state fluorescence spectra were applied to evaluate the luminescence properties of the phosphors. The results indicated that significant enhancement on Tb3+ luminescence was successfully realized by the Ce3+-induced resonance energy transfer and confirmed that the energy transfer from Ce3+ to Tb3+ was governed by an electronic dipole-dipole interaction. Compared to the CSB:Tb3+ phosphors whose optimal excitation located at 378 nm, the occurrence of Ce3+-Tb3+ energy transfer not only allowed the optimal excitation to peak at around 390 nm but also gifted the CSB:Ce3+,Tb3+ phosphors color tunability from blue, cyan to green. Then, two different designs of white light by the introduction of Mn2+ luminescence were performed. One was the combination of CSB:Ce3+,Tb3+ and CSB:Ce3+,Mn2+ phosphors, based on the co-excitation of the above two phosphors at the same wavelength. Another was the direct use of the tri-doped CSB:Ce3+,Tb3+,Mn2+ phosphors. Both designs succeeded in the generation of white light emission. The performance of these two designs in real devices were also studied. The direct use of the tri-doped CSB:Ce3+,Tb3+,Mn2+ phosphor in white light-emitting diode (WLED) device can produce white light with a color rendering index (CRI) up to 85.3 while the use of the CSB:Ce3+,Tb3+ and CSB:Ce3+,Mn2+ phosphors combination can just produce a value of 76.6 in CRI.

Energy transfer from self-trapped excitons to rare earth ions in Cs2ZrCl6perovskite variants

A series of Tb3+-doped Cs2ZrCl6perovskite variants are designed based on energy transfer, and the relationships among intrinsic self-trapped excitons, sub-band gap defects and rare earth ions Tb3+were established.

Luminescence and energy transfer performances of Tb3+/Mn4+ co-doped Sr2LuTaO6 double-perovskite phosphors for a highly sensitive optical thermometer.

A series of Tb3+/Mn4+ co-doped double-perovskite oxides Sr2LuTaO6 (SLT) phosphors are synthesized by a solid-state method. The results of structural characterization prove that the Tb3+ and Mn4+ ions are successfully doped into the SLT host. The photoluminescence excitation (PLE) and photoluminescence (PL) spectra of Sr2LuTaO6:Tb3+, Sr2LuTaO6:Mn4+ and Sr2LuTaO6:Tb3+/Mn4+ are illustrated in detail. Under ultraviolet (UV) excitation, bright green and red lights are obtained from the Sr2LuTaO6:Tb3+/Mn4+ phosphor. In particular, the emission intensity of Tb3+ ions in Sr2LuTaO6:Tb3+/Mn4+ is enhanced by the energy transfer (ET) process from Mn4+ to Tb3+. The thermal enhancement of Tb3+ ion radiation in Sr2LuTaO6:Tb3+/Mn4+ also proves the ET process (Mn4+ → Tb3+). In addition, the thermal enhancement of Tb3+ ion radiation and the thermal quenching of Mn4+ ion radiation in the Sr2LuTaO6:Tb3+/Mn4+ system can be applied to develop optical thermometry based on luminescence intensity ratio (LIR) technology. Therefore, the LIRs of Mn4+ (2Eg → 4A2g) and Tb3+ (5D4 → 7F5,4) are investigated in the temperature range from 313 to 573 K. The absolute sensitivity (Sa) and relative sensitivity (Sr) of the Sr2LuTaO6:Tb3+/Mn4+ phosphor are calculated. The maximum values of Sa and Sr are obtained from the LIR of Tb3+: 5D4 → 7F4 (570-599 nm) and Mn4+: 2Eg → 4A2g (625-705 nm). The maximum Sa is 10.18% K-1 at 543 K, and the maximum value of Sr reaches 1.98% K-1 at 543 K. These results confirm that the ET process from Mn4+ to Tb3+ contributes to increasing the temperature measuring sensitivity of the Sr2LuTaO6:Tb3+/Mn4+ phosphor. Therefore, the Sr2LuTaO6:Mn4+/Tb3+ phosphor has prospective potential in optical thermometry and provides advantageous guidance for designing high-sensitivity optical thermometers.

Enhanced luminescence properties and device applications of Tb3+-doped Cs4PbBr6 perovskite quantum dot glass

Cs4PbBr6 perovskite quantum dots (QDs) have unique optoelectronic properties and are expected to become a new generation of luminescent materials. However, poor stability, low photoluminescence quantum yield (PLQY), and poor understanding as to the origin of photoluminescence behavior limit its further application. In this study, a series of Tb3+-doped Cs4PbBr6 perovskite QD glasses with excellent stability were obtained through the optimization of Tb3+ doping concentration and in-situ crystallization temperature. Density functional theory calculations and experimental characterization showed that an appropriate amount of lattice-incorporated Tb3+ ions can reduce structural defects in QDs, improve the PLQY, and reduce the QD heavy-metal requirements. Notably, the maximum PLQY value reached 47%, which is near to the Cs4PbBr6 perovskite crystal. Furthermore, a high-performance white light-emitting diode (WLED) device was prepared. The device featured a color rendering index of 80 and luminous efficiency of 41 lm W−1. Finally, a QD glass with double emission peaks was prepared by controlling the in-situ crystallization temperature (550 °C). The temperature sensitivity of the QD glass was then studied using the fluorescence intensity ratio method. The maximum relative temperature sensitivity (Sr) reached 2.03% K−1, which is higher than the previously reported value. Thus, the method proposed in this study can greatly improve the photoluminescence properties of Cs4PbBr6 QD glass and expand its applications in WLED and visual temperature sensing.

Synthesis of SrSiO3:Tb3+, Eu3+, Li+ red phosphors for WLED and study of their luminescence properties

A series of Tb3+, Eu3+, Li+ co-doped SrSiO3 phosphors were prepared using the high-temperature solid-phase method. The X-ray diffraction results showed that Tb3+ and Eu3+ successfully entered into the SrSiO3 matrix lattice. Strong energy transfer from Tb3+ to Eu3+ is exhibited with a calculated energy transfer efficiency of 94.7%. Doping of the charge compensator Li+ increased the luminescence intensity of the SrSiO3:6%Tb3+, 6%Eu3+, 3%Li+ phosphor at a wavelength of 614 nm by 4.2 times and significantly improved the color purity of this phosphor (C p = 85.9%). Based on color coordinate analysis, the phosphor color coordinates are located near (0.615, 0.365), which belongs to the red region. The phosphor was integrated into a white LED. The resultant package exhibited a color temperature of 6479 K and a color rendering index of 93.8. Its luminous performance was also very stable under different drive currents.

Single-component white emitting phosphor Mg2Y2Al2Si2O12:Tb3+, Eu3+, Tm3+ for white LEDs

A series of Tb3+, Eu3+, Tm3+ doped Mg2Y2Al2Si2O12(MYAS) phosphors were synthesized by high temperature solid-state method. The emission spectra and energy transfer between lanthanide ions in the materials were studied in detail. Under the excitation of near ultraviolet light, the emission spectra of Mg2Y2Al2Si2O12:Tb3+, Eu3+, Tm3+ phosphors show visible emission peaks of Tb3+, Eu3+, Tm3+, mainly including 1D2→3F4 electron transition (blue light) of Tm3+, 5D3→7FJ (J=4, 5, 6) and 5D4→7FJ (J=3, 4, 5, 6) electron transition (green light) of Tb3+ and 5D0-7F1, 5D0-7F2 and 5D0-7F3 electron transition (red light) of Eu3+. By measuring the emission spectrum, excitation spectrum and fluorescence lifetime of Mg2Y2Al2Si2O12:Tb3+, Eu3+ and Mg2Y2Al2Si2O12:Tm3+, Eu3+ phosphors, it is proved that the energy transfer mechanisms between Tb3+-Eu3+ and Tm3+-Eu3+ in the matrix Mg2Y2Al2Si2O12 are dipole-quadrupole interaction and dipole-dipole interaction, respectively. By changing the concentration of Tb3+, Eu3+, Tm3+ in the matrix, phosphors with adjustable colors from green to red and from blue to red can be obtained, importantly, Mg2Y2Al2Si2O12:0.03Tb3+, yEu3+, 0.05Tm3+ can emit white light with good temperature stability by the energy transfer.

Extending the afterglow of Tb3+ doped CaAl2O4 to 8 hours via the control of doping concentration

With doping concentration varying from 0.1 to 8.0 mol%, a series of Tb3+ doped CaAl2O4 phosphors were prepared via the technique of solution combustion, and the influences of doping concentration on the afterglow of Tb3+ doped CaAl2O4 were investigated. The green afterglow of Tb3+ doped CaAl2O4 is found to heavily depend on the doping concentration and 8-h-long afterglow is achieved at optimal doping concentration of 2.0 mol%. Analysis of the thermoluminescence glow curves reveals that the trap depth in Tb3+ doped CaAl2O4 varies in the range of 0.692–0.728 eV as the doping concentration increases from 0.1 to 8.0 mol%. The large scale extension of the afterglow of Tb3+ doped CaAl2O4 is discussed in terms of the effective manipulation of the trap depth by the variation of Tb3+ concentration. These results demonstrate that tailoring of the trap depth offers a promising approach for controlling the afterglow lifetime of other materials. The finding helps in designing better afterglow materials by optimizing the doping concentration.

Luminescence properties of Tb3+/Eu3+ co-doped glass based on GSBR system

In this work, a series of Tb3+/Eu3+ co-doped GeO2-SiO2-BaO-R2O3 (GSBR) glass were synthesized through high temperature melt cooling method. Luminescence properties of Tb3+/Eu3+ co-doped glass were studied by fluorescence spectrum, fluorescence lifetime and CIE coordinate. The energy transfer efficiency and probability were calculated by average donor distance and lifetime data, revealing that the type of energy transfer is the electric dipole-electric dipole interaction for Tb3+→Eu3+. And the efficiency of energy transfer from Tb3+ to Eu3+ increased greatly by increasing Eu3+ concentrations, which play an important role in adjusting the color at the excitation of 378 nm. The effects of different R2O3 (Gd2O3, Al2O3, Ga2O3) in the matrix on the luminescence intensity of the glass samples were compared. It was found that the luminescence intensity order of samples was Al2O3>Ga2O3>Gd2O3. Through the analysis of infrared and fluorescence spectra, the effects of different matrices components on the structure and luminescence properties of glass were revealed.

Synthesis of color-tunable Sr8MgLa(PO4)7:Eu3+/Tb3+ phosphors for designing dual-model thermometers

A series of Tb3+ and Eu3+ ions single and co-doped Sr8MgLa(PO4)7 (SMLPO) phosphors have been successfully prepared. The SMLPO:0.3 Tb3+/yEu3+ phosphors exhibit color-tunable performances while the energy transfer mechanism between Tb3+ and Eu3+ is determined to be the quadrupole-quadrupole interaction. Besides, the dual-model techniques for optical thermometers based on the ratiometric emission peak and fluorescence lifetime are introduced. The sensing sensitivity is investigated by using the integral intensity ratio between the Eu3+ (5D0→7F2, 616 nm) transition and the Tb3+ (5D4→7F5, 544 nm) transition, and its maximum relative sensitivity (SR1) value reaches up to be 1.3 % K−1 at 573 K. Meanwhile, the temperature-sensitive characteristic based on the fluorescence lifetime is identified by fitting the temperature variable lifetime while the obtained SR2 is found to be about 0.7 % K−1 at 573 K. These results demonstrate that SMLPO:Tb3+/Eu3+ phosphors with color-tunable performances and good sensing sensitivities are potential for dual-model thermometers.