Increase Of Tb3 Research Articles

Blue-green emitting ZnS0.75O0.25:Ce3+,x%Tb3+ phosphor with tunable fluorescence lifetime

A series of ZnS0.75O0.25:0.1%Ce3+,x%Tb3+ phosphors were prepared by high temperature solid state reaction method. These phosphors exhibited two mixed phases consisting of hexagonal phase ZnS and hexagonal phase ZnO with the average particle size of 13.83 μm and emitted blue-green light. The luminescence mechanism consisted of Zn vacancy defects, the 5d1 → 2F5/2 radiative transitions of Ce3+, the 5D4 → 7F5 and 5D4 → 7F6 radiative transition of Tb3+ induced by the energy transfer of Ce3+ → Tb3+. An equation for the variation of the fluorescence lifetime of ZnS0.75O0.25:0.1%Ce3+,x%Tb3+ phosphors with concentration of Tb3+ fraction was obtained by exponential fitting. The short fluorescence lifetime could be tuned within the range of 113 μs to 550 μs with the increase of Tb3+ concentration, and the color was tunable from blue to blue-green, which is of important application in the field of high-energy particle detection.

CeF3-TbF3-YF3 nanoparticles for ratiometric temperature sensing

The Ce0.5Y0.5-XTbXF3 (X = 0.01, 0.02, 0.05, 0.1, and 0.5) nanoparticles demonstrated a single-phase hexagonal structure corresponding to CeF3 host. The average diameter was 15 ± 1 nm. Under Ce3+ excitation at 266 nm, the luminescence peaks of (5d – 4f) Ce3+ and 5D4 – 4FJ (J = 6, 5, 4, and 3) Tb3+ were observed. The emission peaks from 5D3 level of Tb3+ were not observed. We took the luminescence integrated intensity ratio (LIR) of Ce3+ and Tb3+ peaks as a temperature-dependent parameter (303–523 K range). The LIR functions decay with the temperature increase. Indeed, with the temperature rise, the depopulation rate of Ce3+ excited state by Tb3+ becomes higher (phonon-assisted process). Thus, the ICe/ITb decreases. However, the rate of the LIR decay decreases with the increase of Tb3+ concentration. It was suggested, that this phenomenon is related to the presence of two competing processes populating the 5D4 state of Tb3+. There are phonon-assisted non-radiate transition from 5D3 to 5D4 of Tb3+ and cross-relaxation between Tb3+ ions, which was considered less temperature-dependent. The contribution of less temperature-dependent cross-relaxation process to the population of 5D4 increases with the Tb3+ concentration increase compared to 5D3 – 5D4 non-radiative transition. More significant contribution of the cross-relaxation leads to the decrease in the LIR descent rate. The maximum Sa and Sr values were 0.19 K-1 and 1.74 %/K at 303 K, respectively.

Structural and tunable optical properties of LiMgPO4:Tb3+ phosphor fabricated by sol–gel method

AbstractIn the study, Tb3+‐doped LiMgPO4 phosphors between .10 and 5 mol% were successfully synthesized by the sol–gel process. The crystal structure of Tb3+‐doped LiMgPO4 was identified by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and X‐ray photoelectron spectroscopy (XPS) analyses. The XRD results for LiMgPO4 ceramics doped with Tb3+ indicated a single‐phase up to 5 mol%, accompanied by lattice shrinkage. An SEM analysis of LiMgPO4 samples showed that increasing Tb3+ concentration reduced grain size but did not cause any significant change in slightly angular and round grains. The emission intensity of phosphor increased from .10 to 5 mol%, and no concentration quenching was observed. The luminescence color of LiMgPO4:Tb3+ phosphor can be tuned from blue to green through cross‐relaxation with the increase in Tb3+ concentration. The photoluminescence emissions of LiMgPO4:Tb3+ on the CIE diagram shifted from blue to green as the Tb3+ concentration increased. The color purity of the 5 mol% Tb3+‐doped phosphor showing the strongest emission was measured at 22.71%, whereas the color‐correlated temperature parameter was found to be 5573 K. The phosphors exhibited bi‐exponential decay profiles, and the observed lifetimes of 5D3 decreased with the increase of Tb3+, where the cross‐relaxation effect increased. The quantum efficiency (ɳQE) of the phosphor was determined using the cross‐relaxation process. For Tb3+ concentrations ranging from .1 to 5 mol%, the ɳQE of the 5D3 state decreased from 62.49% to 28.29%. The research may offer a new perspective and new approaches for tuning luminescence in Tb3+‐doped phosphors.

Optical properties of Tb3+- and Cr3+-doped MgAl2O4 ceramics prepared by capsule- and carbon-free hot isostatic pressing

Transparent spinel with high real in-line transmittance (RIT up to 79%) was prepared from commercial spinel powder by capsule-free hot isostatic pressing (HIP). Optimal pre-sintering conditions were found in order to enhance the RIT values and doping with Cr3+ (0.01–0.04 at%) and Tb3+ (0.05–0.125 at%) secured photoluminescence. The incorporation of the dopants in tested range does not noticeably reduced the RIT. The Cr3+-doped MgAl2O4 shows efficient narrow red emission at about 685 nm (R-line) due to the 2Eg→4A2g transition of Cr3+ ions located in octahedral sites of D3d local symmetry with a strong crystal field. The Tb3+-doped MgAl2O4 ceramics have shown emissions from blue to red spectral range (5D4→7F3–6 transitions), with prominent green emission centered at 545 nm. The maximal emission intensity was achieved at 0.075 at% of Tb3+, Further increase of Tb3+ content led to the concentration quenching caused by Tb3+ ions segregation at the grain boundaries.

Study on the luminescence characteristics of Tb3+-doped TeO2-Bi2O3-BaF2 glass for blue-green laser emission

In this study, we prepared Tb3+-doped bismuth tellurite glasses by a high-temperature melting method. The matrix glass was characterized by higher thermal stability (ΔT = 102 °C) and lower maximum phonon energy (614 cm−1). Based on absorption spectra, Judd-Ofelt analysis revealed the spontaneous radiation transition probability (269.34 s−1) and fluorescence branching ratio (41.55%) of 5D4→7F5 transition. The luminescence peaks of the samples were located at 486 nm and 545 nm blue-green bands. Meanwhile, the luminescence intensity increased with the increase of Tb3+ concentration and reached the maximum at 4mol% Tb4O7. In addition, emission cross-section and gain coefficients were calculated in blue wavelength range, the maximum values were 2.01 × 10−22 cm−1 and 2.92 cm−1, respectively. Combining all the above results, Tb3+ doped bismuth tellurite glass had potential application value in the field of blue-green communication.

Novel efficient SrMgY3(SiO4)3F:Ce3+,Tb3+ phosphor with tunable color and thermal stability through energy transfer

AbstractA novel apatite‐type SrMgY3(SiO4)3F was synthesized by a high‐temperature solid‐state reaction. The crystal structure was refined using powder X‐ray diffraction data. SrMgY3(SiO4)3F crystallizes in P63/m hexagonal space group with lattice parameters of a = b = 9.45270 Å, c = 6.77617 Å, and V = 524.357 Å3. The incorporation of the Ce3+ and Tb3+ ions into the matrix can generate bright blue and green lights under ultraviolet (UV) light excitation. The codoped Ce3+ and Tb3+ in SrMgY3(SiO4)3F can effectively improve green emission intensity and thermal stability through the energy transfer from the Ce3+ to Tb3+ ions. With the increase of Tb3+‐doping content, the luminescent color of phosphor changes from blue to cyan and finally to green. SrMgY3(SiO4)3F:0.06Ce3+,0.90Tb3+ phosphor exhibited intense green light emission with a quantum yield of 59.49% and good thermal stability, with an emission intensity at 150°C was 96% of that at 30°C. Finally, the prepared sample was coated on 365 nm UV chips to fabricate white light‐emitting diodes with a color rendering index of 82.6 and a correlated color temperature of 2912 K, demonstrating its potential for applications in display and lighting.

Emission-enhanced high-performance Al2O3–Ce: (Y, Tb)AG composite ceramic phosphors for high-brightness white LED/LD illumination

Owing to their excellent thermal robustness, high light saturation threshold, and high luminous efficiency, Al2O3–Ce doped garnet composite ceramic phosphors (CCPs) have attracted extensive attention for applications in laser illumination. In this study, we fabricated the high-performance Al2O3–Ce: (Y, Tb)3Al5O12 CCPs via a solid-state reaction. It was found that the bidirectional energy transfer process between Ce3+ and Tb3+ can promote the absorption of Ce3+ for blue light, which can effectively enhance the yellow light emission intensity and reduce the correlated color temperature (CCT) of samples. Based on this effect, Al2O3–Ce: (Y0·9Tb0.1)3Al5O12 CCPs show the best thermal quenching and luminous efficiency performance. Its luminous efficiency at 450 K drops by 17% from the initial luminous efficiency, and its luminescence efficiency reaches 262 lm/W when driven by a 2.24 W blue laser. In addition, the CCT of samples gradually decreases from 8329 K to 4460 K with the increase of Tb3+, which is of great significance for realizing the white LD lighting.

Photoluminescence of green nanophosphors Sr2MgSi2O7 doped with Tb3+ under 374-nm excitation* *Project supported by the National Natural Science Foundation of China (Grant No. 11004092) and the Foundation of Science and Technology Department of Liaoning Province, China (Grant No. 201602455).

A series of Sr2MgSi2O7:Tb3+ nanophosphors is prepared using a high-temperature solid-state reaction. The x-ray diffraction patterns show that the crystal structure of the sample is not significantly affected by Tb3+ ions. However, the images of the scanning electron microscope illustrate that the average size of nanoparticles becomes larger with the increase of Tb3+ concentration. Unlike earlier investigations on down-conversion emission of Tb3+ ion excited by deep ultraviolet light, in this work, the photoluminescence characteristics of Sr2MgSi2O7 nanophosphors doped with different Tb3+ concentrations are analyzed under 374-nm excitations. The intense green emission at 545 nm is observed at an optimal doping concentration of 1.6 mol%. The main reason for the concentration quenching is due to the electric dipole–electric dipole interaction among Tb3+ ions.

Preparation and luminescence properties of ZnWO4: Tb3+/Yb3+ glass ceramics

Tb3+/Yb3+ co-doped glass ceramics containing ZnWO4 crystals were prepared by melting crystallization method. The effects of Tb3+ and Yb3+ doping on the crystal phase and luminescence properties of glass ceramics were studied. The XRD analysis confirmed the existence of ZnWO4 crystals in glass ceramics, with the increase of Tb3+ doping concentration, the crystal phase changed to Na0.5Tb0.5WO4. The effect of heat treatment time and doping concentration of Tb3+ on the luminescence performance of the glass ceramics were studied to determine the optimal doping concentration of Tb3+. When the concentration of Tb2O3 is 0.1 mol%, with the increase of Yb2O3 doping concentration, the crystal phase of glass ceramics changes from ZnWO4 to Na0.5Yb0.5WO4. The up-conversion luminescence performance of Tb3+/Yb3+ co-doped glass ceramics was studied, and the optimal doping concentration ratio between Tb2O3 and Yb2O3 is determined to be 1:7.

Ionic liquid-assisted hydrothermal synthesis and luminescence properties of Na3Y1−x(PO4)2: xTb3+ phosphors

In this study, a series of spindle-like Na3Y1−x(PO4)2: xTb3+ phosphors have been controllably synthesized by an ionic liquid-assisted hydrothermal route. The structures and morphologies of the as-synthesized products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Photoluminescence spectroscopy (PL), fluorescence decay, and temperature-dependent emission spectroscopy were adopted to characterized the luminescence properties of the samples. The excitation spectra of Na3Y1−x(PO4)2: xTb3+ comprised several well-resolved absorption bands at 273, 285, 304, 318, 340, 352, 368, and 378 nm. When excited at 368 nm, Na3Y1−x(PO4)2: xTb3+ phosphors could exhibit emission bands at 490 nm (5D4 → 7F6), 545 nm (5D4 → 7F5), 586 nm (5D4 → 7F4), and 624 nm (5D4 → 7F3), respectively. The concentration quenching occurred when x is beyond 0.22. The decay time of the photoluminescence of Na3Y1−x(PO4)2: xTb3+ decreased with the increase of Tb3+ doping, which demonstrated the existence of energy transfer among Tb3+ ions. The Commission Internationale de L’Eclairage (CIE) chromaticity coordinates of Na3Y0.78(PO4)2: 0.22Tb3+ were (0.3273, 0.5199) at 273 K, which located in the green region. The temperature dependence experiments revealed that the title material had excellent luminescence thermal stability. The luminescence intensity of Na3Y0.78(PO4)2: 0.22Tb3+ phosphor at 473 K declined 22.1% to its initial intensity. The title material could be used as green light-emitting phosphor for cold white LED applications.

Colour-tunable luminescence and thermal stability of blue-green emitting Ba2MgSi2O7: Ce3+, Tb3+ phosphors

A series of Ba2MgSi2O7: Ce3+ and Ba2MgSi2O7: Ce3+, Tb3+ phosphors were successfully prepared using solid state reaction method. The XRD and FESEM results revealed that the prepared samples have a tetragonal crystal structure and the particles have irregular shapes and different size distributions. The Photoluminescence properties illustrate that Ce3+ doped Ba2MgSi2O7 (BMS) phosphors produced a broad single peak at the wavelength 435 nm under the excitation wavelength 326 nm. BMS: Ce3+, Tb3+ phosphors showed emissions bands for Ce3+ ion as well as Tb3+ ion under the excitation wavelength 252 nm. The energy transfer from Ce3+ to Tb3+ ion was investigated in detail. The emission colors were tuned from blue to green with the increase of Tb3+ concentration in BMS: 1.5 mol% Ce3+ phosphors. The energy transfer from Ce3+ to Tb3+ ions was ascribed to quadrupole-quadrupole interaction. The prepared phosphor showed an excellent thermal stability.

Rare earth ion Tb3+ doped natural sodium feldspar (NaAlSi3O8) Luminescent properties and energy transfer

In this study, Tb3+—doped natural sodium feldspar (NaAlSi3O8) phosphors have been successfully prepared using high−temperature solid—state method with natural sodium feldspar as a substrate. Energy—dispersive X—ray spectrometry analysis (EDX) of NaAlSi3O8 showed that 0.03 wt% of Eu element was present, and elemental distribution mapping analysis showed that the distribution of trace Eu in minerals was aggregated. The crystal structure and luminescence properties of the natural sodium Eu—containing feldspar and synthetic sodium feldspar NaAlSi3O8:Eu3+, Tb3+ phosphors are discussed in detail. The crystal structure analysis of the samples showed that the Na+ in the natural matrix was partly replaced by the doped Tb3+. Studies on the photoluminescence properties of the samples indicate that Eu does not form a luminescent center in the natural mineral, however, the strong characteristic peak of Eu3+ at 615 nm appears after doping with Tb3+ and the peak at 615 nm increases with the increase of Tb3+ concentration. According to the above spectral results, the energy transfer from Tb3+ to Eu3+ is obtained. Through the measurement and analysis of color coordinates, it is found that with the increase of Tb3+ concentration, the luminescence color of the samples can be regulated in the green to red region. NaAlSi3O8:Eu3+ Tb3+ phosphors has potential application value.

Ca20Al26Mg3Si3O68:Ce3+,Tb3+ Phosphors: Preferential Site Occupation, Color-Tunable Luminescence and Device Application

A novel luminescence material of emitting color-tunable Ca20Al26Mg3Si3O68 (denoted as CAMSO):Ce3+,Tb3+ phosphors have been synthesized via the high temperature solid-phase reaction process. The crystal cell structure, photoluminescence properties and application performance such as thermal stability and LED device performance of the phosphors were researched in detail. CAMSO:Ce3+,Tb3+ phosphors showed multicolor with the different concentration of Ce3+ and Tb3+ ions. Although the concentration of Ce3+ ions was settled and there was the existence of energy transfer from Ce3+ to Tb3+ ions, it was found that Ce3+ ions’ blue light emission intensity showed abnormal increasing with the increase of Tb3+ ions doping concentration. The irregular phenomenon was discussed in detail. The phosphor CAMSO:0.2Ce3+,0.1Tb3+ photoluminescence emission intensity motivated by 374 nm at 150 °C retained about 81% of that measured at room temperature, which demonstrating the good thermal and color stability of the sample. In ad...

Morphology-controlled synthesis and luminescence properties of green-emitting NaGd(WO4)2:Tb3+ phosphors excited by n-UV excitation

Tb3+-doped luminescent materials are widely used as green-emitting materials in the fields of lighting and display. A simple hydrothermal method was used to synthesize NaGd(WO4)2:Tb3+ phosphors without any surfactant or templates. The effects of pH value, reaction time and the doping concentration of Tb3+ on the phase structure, morphology and luminescent properties of the samples were investigated. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrum (EDS), photoluminescence spectra and decay curve were applied to characterize the obtained samples. The results indicate that well-defined uniform square plate-like NaGd(WO4)2:Tb3+ microcrystals can be synthesized at pH 8.0, 453.15 K, reaction time of 20 h. Time-dependent sampling and morphology characterization showed the probable formation mechanism of the square plate-like morphology is: nucleation, dissolution, recrystallization and oriented growth. The main excitation peak at 381 nm corresponding to 7F6→5D3 transition of Tb3+, located in the n-UV region (370–410 nm). Upon excitation with 381 nm, the emission spectrum of NaGd(WO4)2:Tb3+ phosphor showed a typical Tb3+ emission, originated from the 5D4→7FJ (J = 6, 5, 4, 3) transition. The strongest emission peak at 545 nm was attributed to 5D4→7F5 transition, which is located in the green light region. The luminescence intensity for the emissions from 5D4 level increased gradually with the increase of Tb3+ doping concentration and reached a maximum at the doping concentration of 80 mol%, then decreased, implying the occurrence of concentration quenching. The square plate-like NaGd(WO4)2:Tb3+ phosphor achieved the best properties, with the intensive green emission centered at 545 nm under n-UV excitation, indicating that it can be used as green component in n-UV-excited white light emitting diodes.

Photoluminescence of terbium doped oxyfluoro-titania-phosphate glasses for green light devices

Terbium (Tb3+) doped oxyfluoro-titania-phosphate glasses of chemical composition (in mol%), (60 - x) P2O5 – 15 BaF2 – 20 CaF2 – 5 TiO2 – x Tb4O7, x = 0.05, 0.1 and 0.1 were fabricated by usual melt-quenching technique. Photoluminescence (PL) properties of the samples have been investigated by excitation, emission and decay profiles. Upon excitation at 377 nm, the PL spectra exhibit an intense band at 541 nm which corresponds to the 5D4 → 7F5 transition. The intensity ratio of green-to-blue (IG/IB) was found to be 9.2 for 0.1 mol% of Tb3+-doped glass. High-energy absorption bands were not resolved in the absorption spectrum but disclosed in the photoluminescence excitation spectrum. Decay curves were unveiled non-exponential and mono-exponential behaviours for the 5D3 and 5D4 levels, respectively. Lifetime of the 5D3 and 5D4 levels was decreased up to 0.1 mol%, and thereafter it was increased with the increase of Tb3+ ion concentration upon 377 nm excitation. The CIE chromaticity coordinates were supported that the green emission was predominant in Tb3+-doped oxyfluoro-titania-phosphate glasses.

Structural destruction quenching of down- and upconversion emission in CaF2:Yb3+, Tb3+

We observed an unusual luminescent phenomenon of Yb3+ in CaF2:Yb3+, Tb3+. Upon excitation at 380 nm, the downconversion luminescence of Yb3+ ions exhibited a monotonic decreasing trend with the increase of Tb3+ concentration from 0.025 mol% to 1 mol%, which implied a unique quenching mechanism. Its inverse process, the cooperatively sensitized luminescence of Tb3+ ions showed that the upconversion emission also quenched at a low concentration (0.075 mol%) of Tb3+ ions. To explain the above emission quenching phenomenon, we further performed the optically inactive rare earth ion doping experiment and fluorescence dynamic measurements. Finally, we found that the cluster structural destruction quenching mechanism dominated the quench of the down- and upconversion emissions induced by cooperative transitions in CaF2: Yb3+, Tb3+.

Electrospinning preparation and luminescence properties of La2O3:Ce3+/Tb3+ nanofibers

One-dimensional Ce3+ and Tb3+-co-doped La2O3 (La2O3:Ce/Tb) nanofibres were formed using a simple electrospinning technique followed by a calcination process. XRD, SEM, TEM, and photoluminescence (PL) are used to characterise the resulting samples. Through a heat-treatment process at high temperature, the as-prepared samples are well-crystallised with the hexagonal La2O3 structure. The energy transfer process from Ce3+ to Tb3+ in La2O3:Ce3+/Tb3+ nanofibres was also studied at fixed Ce3+ concentrations and changed Tb3+ concentration. The results show that the green light of Tb3+ became stronger with the increase of Tb3+ concentrations. The fluorescence lifetime of Tb3+ 5D0 level first increases with the increase of doping concentration and reaches its maximum at 10 mol%, and then decreases.

Tunable blue-green color emitting phosphors Sr3YNa(PO4)3F:Eu2+, Tb3+ based on energy transfer for near-UV white LEDs

A series of Eu2+ and Tb3+ doped Sr3YNa(PO4)3F phosphors have been synthesized via a high temperature solid state reaction method. Eu2+ activated Sr3YNa(PO4)3F phosphors can be efficiently excited by light in the range of 220–420nm, which matches well with the commercial n-UV LEDs, and show intense blue emission centered at 456nm. The optimal doping concentration of Eu2+ is determined to be 1mol%. The concentration quenching mechanism of Eu2+ in SYNPF host is mainly attributed to the dipole-dipole interaction. Energy transfer from Eu2+ to Tb3+ is observed when Eu2+ and Tb3+ are co-doped into Sr3YNa(PO4)3F host. Under excitation of 380nm, the emission color can be varied from blue to green along with the increase of Tb3+ doping concentration. Based on decay curves, the energy transfer from the Eu2+ to Tb3+ ions is demonstrated to be a dipole–dipole mechanism. According to thermal quenching study by yoyo experiments of heating-cooling, Sr3YNa(PO4)3F:Eu2+, Tb3+ shows good thermal stability. The thermal quenching mechanism is also discussed. The results indicate that as-prepared samples might be of potential application in w-LEDs

High thermal stability and quantum yields of green-emitting Sr3Gd2(Si3O9)2:Tb3+ phosphor by co-doping Ce3+

A series of Tb3+ mono-doped and Ce3+-Tb3+ co-doped Sr3Gd2(Si3O9)2 phosphors with high thermal stability and quantum yields were successfully prepared via the solid state reaction. The as-prepared Sr3Gd2(Si3O9)2:Tb3+ samples showed broad excitation spectrum from 250 to 400 nm and presented characteristic emission transitions 5D4→7FJ (J=6, 5, 4, 3) of Tb3+ under 313 nm excitation, which were located at about 488, 541, 584 and 620 nm. The emission intensities of Tb3+ rose steadily in Sr3Gd2(Si3O9)2 host with the increase of Tb3+ concentration even though Gd3+ ions were completely replaced by Tb3+ ions. The Ce3+ ion as a sensitizer could efficiently improve the performance of Tb3+ ion. First, with Ce3+ co-doping, the excitation spectrum of Tb3+ monitored at 541 nm showed a similar band that responds to the violet emission of Ce3+ monitored at 416 nm. Second, the quantum yields of Sr3Gd2(Si3O9)2:Tb3+ phosphors could be enhanced from 26.6% to 80.2% by co-doping Ce3+. Finally, the co-doping of Ce3+ was also effective to improve the thermal stability of Sr3Gd2(Si3O9)2:Tb3+. As the temperature rose to 150 °C, the emission intensity of Tb3+ remained at about 83.6% of that measured at room temperature, which was better than the commercial YAG:Ce phosphor in terms of their thermal quenching properties. These results indicated that the as-prepared Sr3Gd2(Si3O9)2:Tb3+,Ce3+ samples could be used as green emission phosphors for possible applications in near ultraviolet based WLEDs.

Spectroscopic and energy transfer properties of Dy3+-doped, Tb3+/Dy3+-codoped dense oxyfluoride borogermanate scintillating glasses

Dy3+-, Tb3+-activated, and Tb3+/Dy3+-coactivated oxyfluoride borogermanate scintillating glasses with the density of about 6.50 g/cm3 were successfully synthesized by a melt-quenching method. The structure and optical properties including transmittance, photoluminescence (excitation and emission spectra), photoluminescence decay, and X-ray excited luminescence (XEL) behaviors were studied in detail. Our results reveal that the energy transfer efficiency from Dy3+ to Tb3+ ions increases with an increase of Tb3+ concentration. The energy transfer mechanism is determined to be electric dipole–dipole interaction. However, the XEL intensity of Tb3+ decreases with the incorporation of sensitizer Dy3+ into borogermanate scintillating glass, which may result from the different mechanisms under ultraviolet light and X-ray excitation.