Energy Transfer Of Ce3 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.

Luminescence properties and energy transfer of Ce3+, Tb3+ codoped Ba2GaB4O9Cl Phosphor

In this paper, a series of Ba2GaB4O9Cl:Ce3+,Tb3+ phosphors were synthesized by the conventional high-temperature solid-state reaction. The incorporation of Ce3+ ions as sensitizers significantly enhances the absorption and luminescence intensity of Tb3+ ions in the Ba2GaB4O9Cl phosphor. The energy transfer from Ce3+ to Tb3+ occurs through the electric quadrupole-quadrupole interaction, with an energy transfer efficiency of 48 %. The internal quantum efficiency of Ba2GaB4O9Cl:Ce3+,Tb3+ phosphor is 39.95 % upon 316 nm excitation. At 423 K, the emission intensity of Ba2GaB4O9Cl:Ce3+,Tb3+ can keep 53.28 % of its initial value at room temperature. All these results indicate that the Ba2GaB4O9Cl:Ce3+,Tb3+ phosphor has potential application for white LED.

Luminescence and energy transfer of Ce3+, Eu2+ Co-doped SrSi2O2N2 phosphors

SrSi2O2N2:Ce3+/Eu2+ phosphors have been synthesized with a high-temperature solid-state reaction method. The result shows that effective energy transfer has occurred between Ce3+ and Eu2+. The energy transfer efficiency was calculated, and the mechanism was determined as dipole-dipole interaction. The Influence of co-doping with a charge compensator M+ (M+ = Li+, Na+, K+) on the photoluminescence properties of SrSi2O2N2:Ce3+/Eu2+ was analyzed. It is clear that the PL properties of the SrSi2O2N2:Ce3+/Eu2+ phosphor are significantly improved by doping with Li+/Na+/K+, and the Li+ ions is the best charge compensator for this phosphor.

Luminescence and energy transfer of Ce3+/Tb3+ activated fluoroborate BaGaBO3F2 as a color tunable phosphor

Ce3+/Tb3+ co-doped BaGaBO3F2 is a new rare-earth activated luminescent material with efficient green luminescence. The phosphor was synthesized via the conventional solid-state reaction and characterized by X-ray powder diffraction, photoluminescence, and decay lifetimes. The Ce3+/Tb3+ co-doped phosphor exhibits an efficient excitation between 280 and 420 nm, making it suitable for commercial near-UV chips. The 4f–5d transitions of Ce3+ sensitizer allow the phosphor to be excited by the near-UV light, resulting in green and blue luminescence from Tb3+ and Ce3+, respectively. By controlling Ce3+/Tb3+ doping, the luminescence color can be tuned from blue to green. The effective transfer of excitation energy from Ce3+ to Tb3+ of BaGaBO3F2 was confirmed by the spectral characteristics and decay lifetimes of samples with different doping concentrations. The dipole-quadrupole mechanism is responsible for the efficient energy transfer from Ce3+ to Tb3+, with a critical distance of 11.69 Å. These results demonstrate that Ce3+/Tb3+ co-doped BaGaBO3F2 is an efficient near-ultraviolet (NUV) excitation phosphor with tunable luminescence from blue to green. This material has the potential to be used as a down-conversion phosphor for NUV light-emitting diodes.

Eu2+/Ce3+-doped NaAlSiO4 selective occupation-induced emission structure unit evolution and its luminescence characteristics

NaAlSiO4: xEu2+,yCe3+ blue-red phosphors were prepared by high-temperature melting-icy quenching-heat treatment. The effects of emission structure unit evolution, microstrain, microcrystalline size and selective occupation on the luminescence characteristics of the prepared phosphor were systematically studied by powder X-ray diffraction pattern (XRD) and photoluminescence spectroscopy (PL). In the structure of NaAlSiO4: 2%Eu2+, 2%Ce3+ hexagonal crystalline sodium nepheline, Eu2+ ions occupy the Na+ (II) position to form a EuNa+(II)2+ luminescent structure unit, and Ce3+ ions occupy the Na+ (I) position to form a CeNa+(I)3+ luminescent structure unit. The NaAlSiO4: 2%Eu2+/NaAlSiO4: 2%Ce3+ emits 555 nm yellow-green light/395 nm blue-violet light under the excitation of 354 nm/298 nm, respectively, which is derived from the 5d-4f transition of Eu2+ and Ce3+. There is energy transfer of Ce3+→Eu2+ in the sodium nepheline matrix, of which the transport pathway is m EuNa+(II)2+ ←O←n CeNa+(I)3+ →O→m EuNa+(II)2+, and the transport mechanism is electric quadrode-electric quadrupole interaction, and the energy transfer efficiency reaches 98.6%. The sodium nepheline NaAlSiO4: 2%Eu2+, 2%Ce3+ phosphor with energy level barrier 0.386 eV, possesses good thermal stability. This single-phase aluminosilicate multicolor phosphor has potential application value for WLED illumination and PDP display.

Luminescence and energy transfer of Ce3+, Eu2+ co-doped Ba2Mg(BO3)2 for potential anti-counterfeiting applications

The phosphors Ba2Mg(BO3)2 activated with Ce3+ and Eu2+ ions are prepared by a solid-state reaction method at high-temperature and the Rietveld structure refinement of the host compound is performed. The synchrotron radiation VUV - UV excitation, UV – vis emission and luminescence decay spectra, as well as the dependencies of luminescence intensity and lifetime on doping content and temperature are systematically investigated. In addition, the electron-vibrational interaction (EVI) of Eu2+ ions with coordination surroundings and the Ce3+→Eu2+ energy transfer (ET) dynamics are studied in detail. Based on above discussion, the potential applications of co-doped phosphors in excitation wavelength and temperature dual-response optical anti-counterfeiting are demonstrated.

Novel insights on energy transfer processes in [Ce4+/Ce3+]-Er3+-doped tellurite glass

Previous works have been already reported on multiphonon-assisted non-resonant energy transfer in Ce3+-Er3+-doped tellurite glasses. However, it is not clear the mechanism of the radiative emission of Er3+ centered at 1530 nm. In this paper, we reported a better understanding of the mechanism of interactions between those two rare-earth ions via a systematic study. For that, we will explore the energy transitions between Ce4+/Ce3+ and Er3+ ions in a tungsten-tellurite glass to both emission (in the near infrared) and upconversion (in the visible) spectrum. Here, Ce4+ and Ce3+ were obtained in an Er3+-doped tellurite glasses via the addition of different concentrations of CeO2 as part of the composition of the samples. Emission spectrum, under a 980 nm excitation, giving rise to a series of interactions between Ce3+↔Er3+ resulting in: (i) a subtle increase of the Er3+ emission intensity in the near-infrared region for 0.1 mol% of CeO2, and then a decrease in the emission for higher CeO2 concentration in both cases without any significant increase in the bandwidth, and (ii) a decrease of the visible upconversion emission intensity with the addition of CeO2. Such interactions are achieved via a coupling yielding and energy transfer from both rare-earth ions.

Luminescence properties and energy transfer of Ce3+/Eu3+ doped GSBA glass

Through the method of conventional high-temperature melting, Ce3+/Eu3+doped GeO2-SiO2-BaO-Al2O3 (GSBA) glasses were fabricated. Photoluminescence spectrum, Fourier transform infrared spectroscopy, absorption spectrum, fluorescence attenuation time and CIE color coordinates were tested to investigate the optical properties and structure of glass. Using the formula of Dexter's energy transfer, the energy transfer from Ce3+ to Eu3+ was studied. The band gap as well as spacing between rare earth ion were obtained by theoretical calculation. The results show that the optimal cerium ion concentration of the Ce3+ doped and Ce3+/Eu3+ co-doped GSBA glass was consistent, which is 0.3 mol%. For the samples only doped with Ce3+, there has no significant changes of glass structure with increasing Ce3+ concentration, and multiple ligands of [GeO4], [GeO6], [SiO4], [SiO4]&[GeO4], [AlO4] and [AlO6] co-existed in glass structure. It is proved that there is energy transfer from Ce3+ to Eu3+ and the form of energy transmission is electric quadrupole-quadrupole transfer. What's noteworthy is that in Ce3+/Eu3+ double-doped glass, the prepared glass material can emit white light through changing the doped concentration of Eu3+ ion, and color temperature is all below 3300 K, which proves the application potential of Ce3+/Eu3+ co-doped germanosilicate glass in the field of warm white LED.

Photoluminescence properties, excellent thermal stability and energy transfer in Ce3+ and Tb3+ co-doped Sr3Gd2(BO3)4 phosphors

Sr3Gd2(BO3)4: Ce3+, Sr3Gd2(BO3)4: Tb3+ and Sr3Gd2(BO3)4: Ce3+, Tb3+ phosphors were synthesized through conventional high temperature solid state reaction method. Phase purity, crystal structure, photoluminescence properties, and lifetime of the samples were analyzed in detailed. Sr3Gd2(BO3)4: Ce3+ showed a bright blue broad emission band, which was attributed to 4f → 5d transitions of the Ce3+ ions, and it exhibited two broad excitation ranged from 200 nm to 400 nm. For all Sr3Gd2(BO3)4: Tb3+ samples, under ultraviolet excitation bands of 240 nm, four emissions peaked at 490 nm, 544 nm, 585 nm and 623 nm appeared, due to the 5D4 → 7FJ (J = 6, 5, 4, 3) transitions of Tb3+ ions. For the Sr3Gd2(BO3)4: Ce3+, Tb3+ phosphors, the lifetime of the samples were analyzed, which showed the presence of energy transfer between the Ce3+ and Tb3+. The energy transfer efficiency from Ce3+ ions to Tb3+ ions reached 98.37%. When the temperature reached 443 K, the luminescence intensity reached 88% of the initial value. Finally, a white LED was fabricated by using a 365 nm near ultraviolet LED chip combined with BaMgAl10O17: Eu2+ (blue), Sr3Gd0.91(BO3)4: 0.09Ce3+, 1.0 Tb3+ (green), and CaAlSiN3: Eu2+ (red) phosphors. The color coordinates was (0.40, 0.42); correlated color temperature was 3721 K; color rendering index was 91.1. The results showed that the Sr3Gd2(BO3)4: Ce3+, Tb3+ green phosphors were suitable for white LEDs.

Luminescence and energy transfer of Ce3+/Gd3+/Tb3+/Eu3+ doped hexagonal fluoride

Down-shifting luminescence (DSL) of Rare Earth doped hexagonal fluoride has been utilized for multiple potential applications. However, the DSL energy transfer (ET) mechanism still remains rough sketch. In this work, we synthesized a series of hexagonal fluoride NaREF4 with different components and filled up the details of the ET mechanism by thoroughly investigating the luminescence behaviors and lifetime decay curves of Ce3+/Gd3+/Tb3+/Eu3+. All samples were identified to be pure hexagonal phase by powder X-ray diffraction (PXRD). 5 ET processes including Ce3+→Gd3+, Ce3+→Tb3+, Gd3+→Tb3+, Gd3+→Eu3+ and Tb3+→Eu3+ were confirmed and the ET efficiencies could reach up to 69.41%, 61.09%, 88.03%, 83.97% and 70.72%, respectively. According to Dexter's theory, dipole-dipole interaction was found to be responsible. Multiple emission colors could be achieved due to efficient ET Tb3+→Eu3+. However, Eu3+ couldn't be sensitized by Ce3+, hence it was necessary to distribute them into different layers or introduce Gd3+ as intermediate bridge to realize the sensitization. The detailed ET mechanism supported by the lifetime decay curves were proposed. These fundamental researches could help to design novel RE activated fluorescent materials.

Study on energy transfer in Ce3+/Sm3+ activated LaSi3N5 phosphor for warm white-light LED

Sm3+, Ce3+ singly doped and Ce3+-Sm3+ co-activated LaSi3N5 were synthesized by a solid-state reaction method. The crystal structure, morphology and luminescent properties of the corresponding samples are characterized. The photoluminescence results demonstrate that LaSi3N5:Ce3+ phosphor has a broad band excitation spectra and emission spectra with peak at 418 nm, while LaSi3N5:Sm3+ phosphor demonstrates characteristics of linear excitation spectra with main peak locating at 407 nm. An apparent spectral crossover between the emission spectrum of LaSi3N5:Ce3+ and excitation spectrum of LaSi3N5:Sm3+ can be observed, pointing to the possibility of energy transfer from Ce3+ to Sm3+, which is further proved by the investigations of diffuse reflectance spectra, emission spectra, and fluorescence lifetime decay curves. The energy transfer efficiency reaches the maximum of 65.5%. The mechanism of energy transfer was determined to be electric dipole-dipole interaction. This study provides a new example for the development of efficient phosphors in Ce3+- Sm3+ codoped nitrides.

Broadband emission of Lu3Mg2GaSi2O12: Ce3+, Sm3+ phosphors and their potential application for w-LEDs

Herein, Lu3Mg2GaSi2O12: Ce3+/Sm3+ (LMGS) phosphors with a garnet structure were synthesized by a high-temperature solid-phase reaction method, and their potential application in w-LEDs was evaluated. In this study, the crystal structure of the phosphor was determined using the Rietveld method and XRD pattern analysis, while the luminescence performance was characterized by the relevant PL spectrum, and then, the energy transfer (ET) mechanism was explored. When subjected to an excitation at a wavelength of 450 nm, the introduction of Sm3+ ions into LMGS: 0.015Ce3+ broadens the broadband emission of Ce3+ ions owing to the co-excitation and ET of Ce3+ and Sm3+. A continuous and controlled variation in the Sm3+ doping concentration facilitates the tuning of color coordinate from green to yellow. The maximum Ce3+→Sm3+ energy transfer efficiency of the sample was 55.64 %. From the viewpoint of practical applications, the sample exhibited excellent thermal stability and water resistance. After combining the LMGS: 0.015Ce3+, 0.03Sm3+ sample with a commercial red phosphor and a blue chip, a warm white LED with a color rendering index of 86.6 and color temperature of 3592 K can be obtained.

Realizing broadband spectral conversion in novel Ce3+,Cr3+,Ln3+ (Ln = Yb, Nd, Er) tridoped near-infrared phosphors via multiple energy transfers

The solar spectral converters mainly involve the energy transfer between two codoped ions. Here, we report a series of Ce3+, Cr3+, Ln3+ (Ln = Yb, Nd, Er) tridoped Gd3Sc2Ga3O12 (GSGO) phosphors with improved absorption and increasing near infrared (NIR) emission. We observed the multiple energy transfer behaviors of Cr3+→Ln3+, Ce3+→Ln3+, Ce3+→Cr3+, and Ce3+→Cr3+→Ln3+ in GSGO matrix. When Ce3+ is introduced into the GSGO:Cr3+,Ln3+ phosphors, the energy transfer of Ce3+→Cr3+→Ln3+ has been realized by utilizing the energy transfer bridge of the Cr3+ ion. Consequently, GSGO:Ce3+,Cr3+,Ln3+ can absorb almost all ultraviolet and visible (UV–Vis) light and produce strong NIR light thanks to the synergistic effect of Ce3+→Cr3+→Ln3+, improving the photovoltaic conversion efficiency of c-Si solar cells. Our results show that the prepared GSGO:Ce3+,Cr3+,Ln3+ have the potential application in the solar spectral material for c-Si solar cells. Meanwhile, the strategy of multiple energy transfers gives a new way to design the spectral conversion materials with wider absorption for c-Si solar cells.

Site occupation and energy transfer of Ce3+-Activated oxynitride Lu4SiAlO8N with broad-cyan-light-emitting property used for WLEDs

The systems of Si-Al-O-N originated from the outstanding nitrogen ceramic of Si3N4 have received considerable attention due to their significant luminescence properties. In this work, to explore its potential in the full-spectrum lighting applications, a novel oxynitride based phosphor Lu4SiAlO8N: Ce3+ was investigated in detail by using the Rietveld refinement, DFT calculations, photoluminescent (PL) and time-resolved PL (TRPL) spectra. The results indicate that Lu4SiAlO8N performs a tight host lattice formed by the edge-sharing LuO6 polyhedrons and (Si, Al) (O, N)4 tetrahedrons; the multiple crystallographic Lu3+ sites in the host lattice contribute to the broad emission band. Under the near ultraviolet (NUV) light excitation, Lu4SiAlO8N: Ce3+ emits a bright cyan light peaked at 470 nm, and its full width at half maximum (FWHM) can reach 120 nm, which well replenishes the “cyan cavity”. Moreover, the energy transfer between the multiple luminescent centers was verified through the TRPL spectra. The temperature-dependent spectra of Lu4SiAlO8N: Ce3+ was measured to prove its acceptably thermal stability. All the results indicate the Lu4SiAlO8N: Ce3+ to be a promising candidate for the application in WLEDs.

Energy transfer mechanism of Ce3+ → Tb3+ → Eu3+ in Ba9Y2Si6O24

Ba9Y2Si6O24 phosphors doped with cerium (Ce3+)-terbium (Tb3+)-europium (Eu3+) were fabricated using solid phase sintering technique. The crystallinity and luminescence characteristics of rare earth ions doped Ba9Y2Si6O24 phosphors were characterized. Energy transfers (ETs) between cerium-terbium-europium ions in Ba9Y2Si6O24 were investigated. We found that ETs between cerium-terbium and terbium-europium occurred but ET of Ce3+ → Eu3+ was prohibited. However, it can be generated by terbium chain. Therefore, red emission corresponding to europium was obtained under UV light excitation and it was enhanced by energy transfers from cerium to terbium and then to europium.

Luminescence properties and energy transfer in Ce3+ and Tb3+ co-doped Sr5(PO4)2SiO4 phosphor

A novel blue-emitting apatite structure phosphate phosphor Sr5(PO4)2SiO4: Ce3+, Tb3+ has been synthesized by a high-temperature solid-state reaction. X-ray diffraction (XRD), scanning electric microscopy (SEM), ultraviolet–visible diffuse reflectance spectra (UV–Vis DRS), photoluminescence excitation (PLE) and emission (PL) spectra were utilized to characterize the samples. The results showed that the Sr5(PO4)2SiO4: Ce3+, Tb3+ samples exhibit a wide and strong emission band located at 405 nm. In addition, the process of energy transfer (ET) from Ce3+ to Tb3+ has been proved to be a dipole-dipole interaction. Importantly, the color of the phosphor emission can be changed by proper tuning of the Ce3+/Tb3+ ratio. Therefore, the prepared phosphors exhibit great potential for applications in the fields of luminescence and display.

Ionic occupation sites, luminescent spectra, energy transfer behaviors in Y3MgAl3SiO12: Ce3+, Mn2+ phosphors for warm white LED

The Ce3+ and Mn2+ doped Y3MgAl3SiO12 (YMAS) phosphors were synthesized by the high-temperature solid-state reaction in 5%H2–95%N2 reduced atmosphere. Rietveld refinement of X-ray diffraction data indicated that 0.08Ce3+-yMn2+ co-doped YMAS phosphors had a garnet type cubic structure with the Ia3‾d space group. Ce3+ occupies the lattice sites of Y3+. Mn2+occupies both lattice sites of MgO6 octahedron and AlO4 tetrahedron, emitting optical lights centered at 613 nm (Mn2+(I)) and 723 nm (Mn2+(II)), respectively. The orange-yellow light with the range of 450 nm–750nm was obtained by the energy transfer of Ce3+−Mn2+ with a maximum value of 69.2% of energy transfer efficiency. The integrated warm white LED produced white light with CRI of 85.4, CCT of 4502 K, and a CIE color coordinate (0.3542, 0.3269). It indicated that the phosphor might be suitable for blue light-excited white LEDs.

Luminescence property, energy transfer and thermal stability of Sr6Ca4(PO4)6F2:Ce3+, Tb3+, Sm3+ for white light emitting diodes

Series of Sr6Ca4(PO4)6F2:Ce3+, Tb3+, Sm3+ are prepared by a high temperature solid state method. Ce3+, Tb3+ or Sm3+ single-doped Sr6Ca4(PO4)6F2 can produce blue, green and red emission under ultraviolet excitation, respectively. However, the emission intensities of Tb3+ and Sm3+ are relatively weak due to their forbidden transition. In order to achieve white light, the spectral property and decay curves of Sr6Ca4(PO4)6F2:Ce3+/Tb3+/Sm3+ are measured, not only the energy transfer of Ce3+-Tb3+, Ce3+-Sm3+ and Tb3+-Sm3+ was demonstrated, importantly, but also the single-phase white emitting phosphor Sr6Ca4(PO4)6F2:0.14Ce3+, 0.07Tb3+,0.13Sm3+ was obtained by the energy transfer.

Luminescence properties and energy transfer of Ce3+/Dy3+co-activated LaAl2.03B4O10.54 phosphors for wLEDs

Dy3+ ions doped inorganic materials have attracted extensive attentions for their peculiar white emission and simple preparing process. However, Dy3+ ions in these materials have low emission intensity due to the weak absorption in ultraviolet spectral region. Ce3+ ions in most of inorganic compounds show a broad emission in ultra-violet region. Thus, Ce3+ is an effective sensitizer for Dy3+. In this work, a sequence of novel white light-emitting phosphors LaAl2.03B4O10.54: Ce3+/Dy3+ was synthesized by high-temperature solid-state reaction method. Under the excitation at 310 nm, the luminescence properties and energy transfer behavior were investigated in detail for Ce3+/Dy3+ co-doped LaAl2.03B4O10.54 phosphors. The energy transfer efficiency from Ce3+ to Dy3+ was calculated to be 56% with the quadrupole–quadrupole interaction mode. The emitting color of the samples can be modulated from (0.210, 0.123) to white region (0.263, 0.237) by properly changing the doping concentration of Dy3+. The results in this work indicate that the color tunable LaAl2.03B4O10.54: Ce3+/Dy3+ phosphors may be a potential single component phosphor in the field of wLEDs.

Study on the mechanism of improved luminescence in SrB2Si2O8: Ce3+/Tb3+ phosphor

SrB2Si2O8: Tb3+ and SrB2Si2O8: Ce3+, Tb3+ phosphors were synthesized through conventional high temperature solid state reaction method. Under near ultraviolet (NUV) excitation of 377 nm, the emission peaks of the SrB2Si2O8: Tb3+ green phosphor located at 489, 544, 585 and 623 nm corresponding to Tb3+ ions energy level transition of 5D4 excitation state to 7F6, 7F5, 7F4 and 7F3 ground states, respectively. The optimal concentration of Tb3+ ions is 11at.%, and the concentration quenching mechanism can be interpreted by the dipole-quadrupole interaction of Tb3+ ions. For the Sr1-xB2Si2O8: Ce3+, xTb3+ phosphors, the maximum luminescence intensity is 21 times higher than that of the single doped Tb3+, which originates from the energy transfer of Ce3+ to Tb3+ ions. The energy transfer efficiency is calculated to be 79.7%, which is caused by the dipole-dipole resonant type. The CIE coordinates of SrB2Si2O8: Ce3+, Tb3+ phosphors change from blue (0.167, 0.071) to green (0.241, 0.546). When the temperature reaches 210 °C, the luminescence intensity reaches 72.20% of the initial value, indicating that the materials have good thermal stability. The above consequences demonstrate that the SrB2Si2O8: Ce3+, Tb3+ phosphors can be used as a candidate for a promising green luminescent phosphor in ultraviolet excited W-LEDs.