Luminescence Properties Of Bi3 Research Articles

The synthesis and luminescence properties of Bi3+/Eu3+ co-doped Gd2O3 phosphors with high thermal stability and tunable emission via energy transfer

In this work, the highly monodisperse (Gd0.99-xBi0.01Eux)2O3 phosphors with spherical morphologies (∼170 nm) are successfully obtained through precursor synthesis via urea-based homogeneous precipitation (UBHP) method, followed by annealing at 1000 °C. The Bi/Eu-doped does not alter the crystal structure, and maintain the cubic structure of the Gd2O3 host. Owing to the Bi3+ occupies two different sites (C2, S6) in Gd2O3 of the cubic phase, the 1S0 → 3P1 transition of Bi3+ has two significant excitation bands (335 nm and 375 nm). By monitoring the excitation at 335 nm and 375 nm, the (Gd0.99-xBi0.01Eux)2O3 phosphors show both Bi3+ (420 nm and 530 nm) and Eu3+ (611 nm) emissions, respectively. The presences of Gd3+ and Bi3+ excitation bands on the PLE spectra by monitoring the Eu3+ emission indicate the Bi3+ → Eu3+ and Gd3+ → Eu3+ energy transfer, respectively, and the energy transfer efficiency is up to 99 %. Meanwhile, the energy transfer mechanism of the (Gd0.99-xBi0.01Eux)2O3 samples is dominated by the dipole-dipole interaction. Under two different excitation wavelengths, the emission intensity varies with the Eu3+ doping content and the quenching concentration is about 3 at%. The calculated value of the critical distance Rc is 12.12 Å, which indicates that the quenching mechanism is mainly caused by the multipole interaction. Meanwhile, the emission color can be tuned though adjusting the Eu3+ content. The temperature-dependent (in the range of 100–500 K) analysis has been obtained, the results indicate the (Gd0.99-xBi0.01Eux)2O3 samples have good thermal stability. The (Gd0.99-xBi0.01Eux)2O3 phosphors developed in this work is expected to be widely used in lighting and optical display applications.

Tunable luminescence and noncontact temperature sensing of oxyfluoride glass ceramics containing Na(Y1.5Na0.5)F6:Bi3+/Eu3+ nanocrystals

The oxyfluoride glass ceramics (GCs) containing novel Na(Y1.5Na0.5)F6 (NYNF) nanocrystals: Bi3+/Eu3+ were successfully fabricated. The results of the transmission electron microscope (TEM) showed that NYNF nanocrystals (40–70 nm) are distributed in the glass matrix. Moreover, the luminescence properties of Bi3+/Eu3+ ions-doped NYNF GCs were tested and analyzed. The NYNF GCs exhibit strong emission at blue (412 nm, Bi3+) and red (613 nm, Eu3+) wavelengths when excited with near-ultraviolet (n-UV) light at 288 nm. The emission color can be adjusted from blue (0.1506, 0.0655) to violet (0.3535, 0.1929) by increasing the Eu3+ ion content. Notably, the sample exhibited significant temperature-sensing characteristics as calculated by fluorescence intensity ratio (FIR), with high relative sensitivity (1.731 % K−1) at 548 K. These findings demonstrate the potential application of NYNF: Bi3+/Eu3+ GCs in achieving tunable multicolor luminescence and noncontact temperature measurement.

Luminescence Properties of Bi3+-doped Sr3B2O6

Luminescence Properties of Bi3+-doped Sr3B2O6

Study on luminescence properties of Bi3+ doped Ba2YAlO5：A wide-band yellow emitting phosphor with excellent thermal stability

The development of phosphors with excellent thermal stability remains a difficult challenge. Here, we synthesized a novel heat-quenching resistant phosphor Ba2YAlO5 doped with Bi3+ by traditional high temperature solid-state method. The crystal structure and luminescence properties of the samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflection (DR) spectra, photoluminescence (PL) spectra and so on. Under 324 nm excitation, the phosphor emits a broad-band yellow light with a peak value of 571 nm and a full width at half maximum (FWHM) of 125 nm. It is worth noting that the integrated emission intensity at 560 K is still close to that at room temperature, which can be attributed to the thermal compensation capability of the electron trap energy levels. The matrix may also have high lattice stiffness to reduce thermal quenching. In addition, Ba2YAlO5: Bi3+ exhibits yellowish white light with CIE coordinates of (0.4203, 0.4536) and a color temperature of 3669 K under excitation of a 310 UV chip. The above results indicate that Ba2YAlO5: Bi3+ is a promising yellow fluorescent powder with excellent luminescence performance for high-power devices.

Structure and luminescence properties of Bi3+-doped ZrSiO4 phosphors for near-UV excited white LEDs

• A novel ZrSiO 4 :Bi 3+ phosphor has been synthesized. • The ZrSiO 4 :Bi 3+ samples exhibit broad emission bands peaked at 548 nm when excited at 361 nm. • The ZrSiO 4 :Bi 3+ phosphors own excellent thermal stability. • The luminescence mechanisms and energy transfer processes are discussed. ZrSiO 4 :Bi 3+ phosphors were synthesized by conventional high-temperature solid-phase method. The structural and optical behaviors were investigated by X-ray diffraction, scanning electron microscope, X-ray photoelectron spectroscopy and photoluminescence spectra. Bi 2 O 3 contributes to the ZrSiO 4 phase generation from liquid phase sintering. The ZrSiO 4 :Bi 3+ shows a broad emission band centered at 548 nm when excited at 361 nm. The Bi 3+ doping concentration is optimized to be 4 mol%, and the luminescence intensity of ZrSiO 4 :0.04Bi 3+ at 150 °C keeps 84% of that at room temperature. The results indicate that the ZrSiO 4 :Bi 3+ phosphors offer more possibilities in the near-UV excited white LED applications.

Synthesis and luminescence properties of Bi3+ activated Ba3WO5Cl2 phosphors for plant cultivation applications

Bismuth is a impressive activator and sensitizer for luminescent material, which has been comprehensively investigated during the recent decades. Bismuth is a chemical element and it is a post transition metal and bismuth is flexible but complex dopant for possible luminescence application study and it has been accumulating to understand the optical properties of bismuth. Proposed work shows the luminescence properties of bismuth doped Ba 3 Wo 5 Cl 2 is successfully synthesized by using solid state diffusion method. X-ray diffraction pattern of prepared phosphor is compared with the standard ICSD database shows the sample is prepared in well manner. Fourier transformation infrared spectroscopy (FTIR) displays the vibrational feature of prepared phosphor. Photoluminescence study demonstrated emission peak of proposed phosphor located at 708 nm due to 4 G 5/2 → 6 H 11/2 at excitation 471 nm. There are several evidences that the peaks observed in the range from 650 to 750 nm are useful in plant cultivation.

Effect of the anion on the luminescence properties of Bi3+-doped X-mayenite (X=O, F, Cl) phosphors

A series of Bi3+-doped X-mayenite (X = O, F, Cl) phosphors was synthesized via the conventional solid-state reaction method. Upon excitation at 325 nm, Bi3+-doped O-mayenite exhibits a single blue emission band peaking at 452 nm, which is assigned to the 3P1→1S0 transitions of Bi3+ ions. For F-mayenite:Bi3+ and Cl-mayenite:Bi3+ phosphors, there is a new dominant ultraviolet emission centered at 375 nm and a weak blue emission. The luminescent dynamical process proves that two emission centers exist in F-mayenite:Bi3+ and Cl-mayenite:Bi3+. Our results confirm that the ultraviolet emission originates from the transitions of Bi3+ with Cl− or F− ions surrounded, and the blue emission corresponds to the transitions of Bi3+ with O2− ions surrounded. In addition, the emission color of Cl-mayenite:Bi3+ can be tuned both by controlling the encaged anions and Bi3+ content. We demonstrate that anion control is a new desirable strategy for photoluminescence tuning.

Color-Tunable Luminescence Properties of Bi3+ in Ca5(BO3)3F via Changing Site Occupation and Energy Transfer

Generally, 6s electron and 6p electron of Bi3+ ions are located in its outermost layer; thus, luminescence properties of Bi3+ are strongly associated with the coordination environment around Bi3+. Bi3+ ions occupy different cationic positions in hosts, which may cause the movement of the emission spectrum. In order to investigate the luminescent property of Bi3+, a series of Bi3+ doped Ca5(BO3)3F species are synthesized. There are three types of Ca2+ sites in the host, which could be substituted by Bi3+. Upon the 322 nm excitation of Bi3+, a broad emission band can be observed, which is ascribed to the 1s0 → 3p1 transition of Bi3+. Meanwhile, there is the emission shift of Ca5(BO3)3F:xBi3+, and its emission color can be altered from blue to cyan. It may result from Bi3+ occupying different positions of Ca2+ in the host, which can give rise to different degrees of a nephelauxetic effect and crystal field splitting. In order to explore the relationship between the luminescence properties of Bi3+ and the nep...

Crystal structure and luminescence properties of Bi3+activated Ca2Y8(SiO4)6O2 phosphors under near UV excitation

Oxyapatite Ca2Y8−x(SiO4)6O2:xBi3+phosphor has been prepared via high temperature solid-state reaction. Its crystal structure and PL properties were investigated by X-ray diffraction, photoluminescence excitation and emission spectra. The results indicated that the Ca2Y8(SiO4)6O2 crystallizes as a hexagonal structure with a space group of P63/m and lattice constants of a=b=9.3507Å, c=6.7899Å, α=β=90.00°, γ=120.00°, V=514.14Å3; The phosphor has two prominent emission bands: when excited under 320–360nm, the phosphors emit a broad band centered at 495nm due to the 3P1–1S0 transition of Bi3+ in 4f (C3) sites; when excited under 380nm, the phosphors emit a broad band centered at 411nm due to the 3P1–1S0 transition of Bi3+ in 6h (Cs) sites. The emission color varies from the greenish blue to blue as the excitation wavelength increases from 335 to 380nm. The optimal intensity of emission band was observed when x=0.015 in the Ca2Y8−x(SiO4)6O2:xBi3+ series. The average critical distance Rc among Bi3+ ions is determined to be 20.15Å.

La3+eliminate the blue component from the emission of Y2O3:Bi3+

A systematic investigation was done on the luminescence properties of Bi3+ doped Y2O3 in the presence of different La3+ ion concentrations prepared by the sol gel combustion method. The results revealed that the incorporation of La3+ ions in the Y2O3 lattice, induced elimination of the blue emission from the Bi3+ ions occupying the S6 side of the Y3+ ion in the Y2O3 lattice. This change in the luminescence properties was attributed to the change in the crystal structure around the Bi3+ ions. The X-ray diffraction technique shows the change in the crystal structure as the results of the La3+ ions incorporation.

Crystal structure and luminescence properties of Bi3+ activated Ca2Y3Sb3O14 phosphors in near UV region

A novel Ca2Y3Sb3O14: Bi3+ phosphor was synthesized and its crystal structure, photoluminescence (PL) properties was investigated. Ca2Y3Sb3O14 crystallized as a monoclinic structure with a space group of I2m/11 and lattice constants of a=7.4129(7)Å, b=10.4428(1)Å, c=7.3898(8)Å and α=90.049°. Ca2Y3Sb3O14: Bi3+ could be efficiently excited in the wavelength range of 270–400nm. With the increase of Bi3+ concentration, the most efficient excitation wavelength of the phosphors moved from 320 to 350nm. When excited under 310–350nm, the phosphors emit a broad band with a maximum intensity appearing at about 420–460nm due to the 3P1–1S0 transition of Bi3+. The relationship between the PL properties and the crystal structure was discussed. Due to the efficient excitation in the near UV region and the strong blue to cyan emission, Ca2Y3Sb3O14: Bi3+ would be a potential blue phosphor for near UV white light-emitting diodes, or a potential donor system for designing single-composition white-light phosphors based on energy transfer.

Luminescence and Energy Transfer in Europium and Bismuth Codoped Trisodium Yttrium Silicates

Bi3+ and Eu3+ doped Na3 YSi2 O7 phosphors are prepared with solid state reactions. The luminescence properties of Bi3+ and Eu3+ in Na3YSi2O7 and the energy transfer (ET) from Bi3+ to Eu3+ are investigated in detail. The ET mechanism is also discussed. Bi3+ in Na3 YSi2 O7 emits near-ultraviolet (UV) light in a broad band peaking at 394 nm which can be attributed to the transition from excited states 3P0,1 to ground state 1S0 under the excitation of UV light with a wavelength of 309 nm. Eu3+ in Na3 YSi2 O7 emits orange and red light. The co-doping of Bi3+ into Eu3+ doped Na3YSi2O7 introduces an intense absorption band from 270 to 350 nm due to ET from Bi3+ to Eu3+. The sensitization effect of Bi3+ on Eu3+ makes it possible that Bi3+ and Eu3+ co-doped Na3 YSi2 O7 could be used in AlGaN-based UV light emitting diodes as a red phosphor.

The luminescence properties of Bi3+ sensitized Gd2MoO6:RE3+ (RE = Eu or Sm) phosphors for solar spectral conversion

Gd2MoO6:RE3+ (RE=Eu or Sm) and Gd2MoO6:Bi3+, RE3+ (RE=Eu or Sm) phosphors have been synthesized by combustion method. The samples are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), photoluminescence excitation (PLE) and photoluminescence (PL) spectra. By introducing Bi3+ ions into Gd2MoO6:RE3+ (RE=Eu or Sm) phosphors, the excitation bands of Eu3+ and Sm3+ ions are broadened and shifted to short wavelength, meanwhile, the emission intensity are enhanced obviously. The energy transfer from Bi3+ to the activators of Eu3+ or Sm3+ is observed and discussed. In addition, the process of ultraviolet light (250–400nm) converted into visible light can be achieved by using Gd2MoO6:Bi3+, RE3+ (RE=Eu or Sm) phosphor. These phosphors can be a promising ultraviolet-absorbing luminescent converter to enhance the photoelectrical conversion efficiency of dye-sensitized solar cells (DSSCs).

Influence of crystal structure on the luminescence properties of bismuth(III), europium(III) and dysprosium(III) in Y2SiO5

The luminescence properties of Bi3+, Eu3+, Dy3+ and energy transfer from Bi3+ to Dy3+ and Eu3+ have been studied in two modifications of Y2SiO5(low-temperature X1 type and high-temperature X2 type) and discussed in relation to their crystal structures. The Bi3+ ion luminesces in the blue region of the spectrum in X1-Y2SiO5 but in the UV region in X2-Y2SiO5. Two obviously different luminescent centres have been observed for Bi3+ and Eu3+ in X1-Y2SiO5, but only one has been seen in X2-Y2SiO5. The Stokes shift (9200 cm–1) for Bi3+ in X1-Y2SiO5 is much larger than that (5000 cm–1) in X2-Y2SiO5. This suggests that the host lattice is more rigid in X2-Y2SiO5 than in X1-Y2SiO5. As a result, the Bi3+, Eu3+ ions show higher emission intensity in the former than in the latter type. X1-Y2SiO5 is more suitable for Bi3+→ Eu3+ energy transfer and X2-Y2SiO5 is more suitable for Bi3+→ Dy3+ energy transfer.

Luminescence of Cs2NaYCl6—Bi3+ (6s2)

AbstractThe luminescence properties of Bi3+‐activated Cs2NaYCl6 crystals are presented. The Bi3+ ion (6s2) occupies an Y3+ site which has cubic symmetry. Excitation in the A absorption band yields 3T1u emission. Excitation in the C absorption band, however, yields 3T1u and 3A1u emission, because both levels are populated by nonradiative processes from the 1T1u excited state. The emission and excitation spectra show vibrational structure. The vibronic lines are assigned and discussed.