Series Of Tb3 Research Articles

High purity green photoluminescence emission from Tb3+, Bi3+ co-doped LaGaO3 nanophosphors

A series of Tb3+ and Bi3+ co-doped LaGaO3 nanophosphors were synthesized by using polyol route and also characterised for their uncovering energy transfer mechanism of photoluminescence. An excellent characteristic emission of Bi3+ and Tb3+ ions was observed with an appreciable increase in photoluminescence at certain doping concentration. Energy transfer (ET) mechanism from the host lattice to Bi3+ and Tb3+ ions in the co-doped nanophosphor has been explained. The ET efficiency has been calculated and found to be 69.53%. The CIE chromaticity of the synthesized LaGaO3: Bi3+, Tb3+ nanophosphors indicates that they could be a suitable material for field emission display and LED applications.

Organic additive assisted hydrothermal synthesis and photoluminescence properties of CeF3:Tb3+ and NaCeF4:Tb3+ nanoparticles

A series of Tb3+ doped CeF3 and NaCeF4 nanoparticles with different morphology and dimension were synthesized via hydrothermal method. Different organic additives, including sodium dodecyl sulfonate (SDS), polyvinylpyrrolidone (PVP), cetyltrimethyl ammonium bromide (CTAB), oleic acid (OA), polyethylene glycol (PEG), trisodium citrate (Cit) were introduced to control the crystallite size and morphology. Powder X-ray diffraction (PXRD), fourier transform infra-red spectra (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and down-conversion (DC) photoluminescence spectra were used to characterize the samples. The emission peaks of all the prepared samples centered at 490, 545, 585 and 621 nm which can be ascribed to the 5D4→7FJ (J = 6, 5, 4, 3) transitions respectively of Tb3+ ion. However, emission intensities are strongly controlled by morphology and particle sizes which are influenced by different organic additives used in synthesis. Moreover, the crystal growth process was monitored through a series of time-dependent experiments and a possible formation mechanism has been proposed.

Tunable Luminescence in Sr2MgSi2O7:Tb3+, Eu3+Phosphors Based on Energy Transfer.

A series of Tb3+, Eu3+-doped Sr2MgSi2O7 (SMSO) phosphors were synthesized by high temperature solid-state reaction. X-ray diffraction (XRD) patterns, Rietveld refinement, photoluminescence spectra (PL), and luminescence decay curves were utilized to characterize each sample’s properties. Intense green emission due to Tb3+ 5D4→7F5 transition was observed in the Tb3+ single-doped SMSO sample, and the corresponding concentration quenching mechanism was demonstrated to be a diople-diople interaction. A wide overlap between Tb3+ emission and Eu3+ excitationspectraresults in energy transfer from Tb3+ to Eu3+. This has been demonstrated by the emission spectra and decay curves of Tb3+ in SMSO:Tb3+, Eu3+ phosphors. Energy transfer mechanism was determined to be a quadrupole-quadrupole interaction. And critical distance of energy transfer from Tb3+ to Eu3+ ions is calculated to be 6.7 Å on the basis of concentration quenching method. Moreover, white light emission was generated via adjusting concentration ratio of Tb3+ and Eu3+ in SMSO:Tb3+, Eu3+ phosphors. All the results indicate that SMSO:Tb3+, Eu3+ is a promising single-component white light emitting phosphor.

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.

NUV excited luminescence studies of Tb3+ in CaTiO3 nanophosphor for wLEDs

A series of Tb3+ doped CaTiO3 (1-9 mol%) nanophosphors were successfully synthesized by a low temperature solution combustion method using ODH as a fuel. The phase and morphology, of the prepared phosphors were characterized by using powder x-ray diffraction (PXRD) and Scanning electron microscopy (SEM) and confirms orthorhombic structure with porous morphology and the size of the crystallites are ∼ 40 nm. Photoluminescence (PL) emission was studied under 377 nm excitation wavelength. PL spectra consists of emission bands corresponding to transition 5D3→7F3 (458 nm) and 5D4→7Fj (j = 6, 5, 4, 3) transitions such as 5D4→7F6 (486 nm), 5D4→7F5 (541 nm), 5D4→7F4 (585 nm) and 5D4→7F3 (622 nm). Among these, the green emission corresponding to 5D4→7F5 (541 nm) transition was the most dominant and the same was confirmed by The CIE coordinates. Thus, the present nanophosphors can be served as an excellent material for solid state lighting applications and for wLEDs.

Crystal structure, tunable luminescence and energy transfer properties of Na3La(PO4)2:Tb3+,Eu3+phosphors

A series of Tb3+and/or Eu3+doped Na3La(PO4)2phosphors were successfully synthesized and their crystal structure and photoluminescence (PL) properties were investigated in detail.

Photoluminescence, energy transfer, and thermal stability of BaAl2Si2O8:Bi3+, Tb3+ phosphors for w-LEDs

A series of Tb3+ or/and Bi3+ doped BaAl2Si2O8 phosphors were synthesized via solid-state method. The structure, luminescence properties and thermal stability were investigated. The optimum concentrations of Bi3+ and Tb3+ were 1.5mol% and 7mol%, respectively. Furthermore, BaAl2Si2O8:0.015Bi3+ and BaAl2Si2O8:0.07Tb3+ phosphors emitted blue and green light and the emission color of BaAl2Si2O8:Bi3+, Tb3+ could be tuned from blue to green through the energy transfer. This energy transfer from Bi3+ to Tb3+ was confirmed and investigated by photoluminescence spectrum and decay lifetime. With constantly increasing Tb3+ concentrations, the energy transfer efficiency from Bi3+ to Tb3+ in BaAl2Si2O8 host increased gradually and reached as high as 86.54%, the quantum yield was about 44.26%. The energy transfer mechanism (Bi3+-Tb3+) was proved to be dipole–dipole mechanism. The Tb3+ emission intensity can be considerably enhanced when monitored at NUV (377nm) by co-doping Bi3+ ion. Moreover, the phosphor of BaAl2Si2O8:0.015Bi3+, 0.07Tb3+ could exhibited strong green emission with good CIE chromaticity coordinate. The results indicate that BaAl2Si2O8:Tb3+, Bi3+ is a potential green emitting phosphor for the application in w-LEDs.

Synthesis, luminescence property and thermal stability of KMgLa(PO4)2:Tb3+ phosphor

A series of Tb3+ doped KMgLa(PO4)2 have been prepared via a high-temperature solid-state method. KMgLa(PO4)2:Tb3+ shows the characteristic green emission, and the peak locates at 546nm, which corresponds to the 5D4→7F5 transition of Tb3+. The emission intensities are influenced by the Tb3+ concentration, and the concentration quenching effect is observed, and the critical distance is calculated to be 1.135nm. Its CIE chromaticity coordinates are shifted from green to greenish-yellow with increasing Tb3+ concentration. The emission intensity of KMgLa(PO4)2:Tb3+ has a good thermal stability, when measuring temperature turned up to 150°C, the emission intensity is about 80.0% of the initial value at room temperature.

Energy transfer, tunable luminescence, and thermal stability of Tb3+–Sm3+-codoped Na3Bi(PO4)2 phosphors

A series of Tb3+–Sm3+-codoped Na3Bi(PO4)2 phosphors have been prepared by a high-temperature solid-state reaction, and their luminescence properties have been investigated in detail. The energy transfer process from Tb3+ to Sm3+ was verified through luminescence spectra and fluorescence decay curves. Moreover, the energy transfer mechanism was demonstrated to be the dipole–dipole interaction and the ET efficiency as well as quantum efficiency was also estimated. By controlling the doping content of the Sm3+ ions with the fixed Tb3+ content, the emission color of the obtained phosphors could be easily modulated from green to yellow and then to yellow-white. Additionally, as the temperature increases from RT to 150 °C, the PL intensity of transition of Sm3+ decreased to 79 %, which prove good thermal stability of Na3Bi(PO4)2:xSm3+,0.1Tb3+ phosphors. All the results indicate that the series of Na3Bi(PO4)2:xSm3+,0.1Tb3+ phosphors can be acted as a good candidate for the application in white light-emitting diodes.

Energy transfer and multicolor emission in single-phase Na5Ln(WO4)4−z(MoO4)z:Tb3+,Eu3+ (Ln = La, Y, Gd) phosphors

A series of Tb3+ and/or Eu3+-doped Na5Ln(WO4)4−z(MoO4)z (0 ≤ z ≤ 4, Ln = La, Y, Gd) phosphors have been prepared via a simple Pechini method.

Lu2O2S:Tb3+, Eu3+nanorods: luminescence, energy transfer, and multicolour tuneable emission

A series of Tb3+ and Eu3+ singly-doped and co-doped rod-like Lu2O2S phosphors have been synthesized via a facile hydrothermal method followed by a subsequent calcination process. The phosphors, with excellent dispersion and uniform rods, exhibit the characteristic Tb3+ or/and Eu3+ emissions with the strongest peaks located at 544 nm (green) and 626 nm (red), respectively. Moreover, the emission intensities of both Tb3+ and Eu3+ remarkably vary with increasing Eu3+ incorporation, and as a result, bright and tunable color emission can be realized in the single-phase Lu2O2S host by varying the ratio of Eu3+ to Tb3+ ions. In addition, the multicolor luminescence of Tb3+ and Eu3+ co-doped rod-like Lu2O2S phosphors can be readily achieved by changing the excitation wavelengths. The energy transfer from Tb3+ to Eu3+ ions in Lu2O2S was systematically investigated in detail. These results prove that the as-synthesized Lu2O2S nanorods are an excellent host for rare earth luminescence, and the Lu2O2S:Tb3+, Eu3+ nanorods with tunable multicolor luminescence properties may have potential applications in the fields of full-color displays, solid-state light and field emission displays.

Tunable multicolor and white luminescence in Tb3+/Dy3+/Mn2+ doped CePO4 via energy transfer

In this paper, a series of Tb3+/Dy3+/Mn2+ doped CePO4 downconversion nanophosphors (DCNPs) were prepared by a one-pot hydrothermal process. The obtained DCNPs presented monoclinic and hexagonal phase structure with wire-like shape. The photoluminescence (PL) properties and the energy transfer (ET) mechanism of these DCNPs were investigated in detail. The ET mechanism of Ce3+/Tb3+ in CePO4 host was calculated by means of concentration quenching and spectral overlapping, and calculation results revealed that dipole–dipole interactions should be more responsible. The maximum value of ET efficiency was measured to 87.4% for Tb3+ doped CePO4 system. In addition, owing to the efficient ET between Ce3+ and Tb3+/Dy3+/Mn2+, these as-prepared DCNPs exhibit tunable multi-color output under ultra-violet (UV) light excitation. More importantly, the intense cold and warm white emissions can be realized by singly doping 2%Dy3+ and 20%Mn2+ in CePO4 host under UV irradiation, respectively. The corresponding CIE 1931 coordinates were calculated to be (0.30, 0.30) and (0.30, 0.32), respectively, which are closed to the standard white emission (0.33, 0.33). These findings demonstrate the efficient white light emission by singly doped Dy3+ or Mn2+ in CePO4 system for the first time, which is different from commonly used co-doped or tri-doped system. The multicolor tuning and white emission make these Tb3+/Dy3+/Mn2+ doped CePO4 DCNPs potential phosphors in the fields of displays, lighting, and field-emission devices.

Photoluminescence properties of solid-state Tb3+ doped NaY(MoO4)2

A series of Tb3+ doped NaY(MoO4)2 are synthesized by a solid-state reaction at 550 °C for 4 h, and their luminescent properties are investigated. The phase formation is carried out with X-ray powder diffraction analysis, and there is no other crystalline phase except NaY(MoO4)2. NaY(MoO4)2:Tb3+ can produce the green emission under 290 nm radiation excitation, and the luminescence emission peak at 545 nm corresponds to the 5D4→7F5 transition of Tb3+. The emission intensity of Tb3+ in NaY(MoO4)2 is enhanced with the increase of Tb3+ concentration, and there is no concentration quenching effect. The phenomena are proved by the decay curves of Tb3+. Moreover, the Commission International de I’Eclairage (CIE) chromaticity coordinates of NaY(MoO4)2:Tb3+ locate in the green region.

Study on the Morphology and Thermal Stability of Li<sub>2</sub>SrSiO<sub>4</sub>: Tb<sup>3+</sup> Materials

A series of Tb3+-doped Li2SrSiO4:Tb3+phosphors were prepared by high temperature solid state reaction. The morphology and the thermal stability of Li2SrSiO4:Tb3+phosphors were discussed by SEM and PL measurements, respectively. The results showed that the morphology of Li2SrSiO4:Tb3+was changed from flower-like to rod-like with increasing Tb3+-doped content. Moreover, the emission intensity measured at 3500C almost maintain with constant compared with that measured at room temperature. The results showed that Li2SrSiO4:Tb3+phosphor might be a potential phosphor for white light-emitting diodes.

Sensitization of Gd3+ ions by Tb3+ ions in Tb3+ doped (La, Gd)PO4

The role of Tb3+ ions, with respect to efficient energy transfer, on sensitization of Gd3+ ions in (La,Gd)PO4 has been investigated. A series of Tb3+ doped (La, Gd)PO4 were characterized by steady state spectroscopy and efficient energy transfer from Tb3+ 4f75d to Gd3+ 4f7 states was observed. The decay curves of Gd3+6P7/2 and Tb3+5D3, 5D4 states upon Tb3+ 4f75d and Gd3+6IJ states excitation were also performed to reveal the energy transfer processes. With the increase of Gd3+ concentration, the energy transfer efficiency increase accordingly. Based on steady state spectra, around 73% energy transfer efficiency in Gd0.99Tb0.01PO4 was determined.

Effect of Tb<sup>3+</sup>-Coped Concentration on Properties of Li<sub>2</sub>SrSiO<sub>4</sub>:Tb<sup>3+</sup> Phosphor

A series of Tb3+-doped Li2SrSiO4phosphors were prepared by high temperature solid state reaction. Effect of Tb3+-coped concentration on luminescence properties of Li2SrSiO4: Tb3+phosphor was investigated by XRD, FTIR, PL and CEI measurements. The results showed that the unit cell constant of Li2SrSiO4:Tb3+was reduced gradually with increasing Tb3+concentration, and then the FTIR absorption intensity assigned to the stretch vibration of [SiO4] and bend vibration of Si-O was decreased. The emission properties of Li2SrSiO4:Tb3+phosphors are strongly dependent on the concentration of Tb3+. The stronger blue and weaker green emission were shown as adding 1% Tb3+amount, while single bright green emission was presented in 20% Tb3+contents. The corresponding CIE was observed from (0.192, 0.315) to (0.246, 0.599). The results showed that the luminescence properties of Li2SrSiO4:Tb3+phosphor could meet various requirements by tuning the Tb3+-doped concentration.