Bright green-emitting, energy transfer and quantum cutting of Ba_3Ln(PO_4)_3: Tb^3+ (Ln = La, Gd) under VUV-UV excitation (original) (raw)
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Novel RGB emission of Tb 3+ ion in Li 2 BaP 2 O 7 phosphor for near-UV LEDs
A red emitting Li 2 BaP 2 O 7 :Tb 3+ phosphor prepared through solid state reaction method is first time reported in this work. The main point of this work is that Tb 3+ shows intense red line in addition to blue and green lines in Li 2 BaP 2 O 7 upon UV excitation. Red line (602 nm) dominates the spectrum upon 372 nm excitation. However, the green line dominates the spectrum upon 230 nm excitation. The results are quite interesting from luminescence point of view. Therefore, we suggest a new red, green and blue emitting Li 2 BaP 2 O 7 :Tb 3+ phosphor for pc-LEDs to generate white light.
Journal of Rare Earths, 2017
A novel fluoro-apatite-type compound, Ba 3 TbK(PO 4) 3 F was developed via a high-temperature solid-state reaction route for the first time. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and high-resolution TEM (HRTEM) were used to investigate the component element and microstructure of the phosphor was systematically investigated. The luminescence properties of Ba 3 TbK(PO 4) 3 F:Sm 3+ were investigated systemically. The results revealed that the Ba 3 TbK(PO 4) 3 F:Sm 3+ phosphor could be efficiently excited in a broad wavelength region ranging from 200 to 400 nm, which matched perfectly with the ultraviolet (UV) light-emitting diode (LED) chips. Based on the energy transfer (ET) between Tb 3+ and Sm 3+ , the color hue of Ba 3 Tb 1-n K(PO 4) 3 F:nSm 3+ (n=0-0.03) was modulated from green (0.305, 0.591) to yellow (0.486, 0.437) area by controlling the Sm 3+ doping concentration. The critical distance between Tb 3+ and Sm 3+ ions in Ba 3 TbK(PO 4) 3 F:Sm 3+ was calculated and the corresponding energy quenching mechanism was identified. Fascinatingly, both the Ba 3 TbK(PO 4) 3 F and Ba 3 Tb 0.995 K(PO 4) 3 F: 0.005Sm 3+ phosphors exhibited very high thermal stability from room temperature (25 ºC) to 300 ºC, which is extremely important for practical application. In addition, the activation energy for thermal quenching of the Ba 3 Tb 0.995 K(PO 4) 3 F:0.005Sm 3+ sample was estimated to be as high as 0.312 eV. These findings demonstrated that as-prepared phosphor may serve as a high-performance candidate for the application in w-LEDs.
Green Light Emitting Tb3+ Doped Phosphors - A Review
Material Science Research India, 2018
WLEDs were the potential materials for significantly improving lighting efficiency, resulting in reduction of the excitation energy and also reduction in pollution from fossil fuel power plants. To enhance the quality of white-light, the researches on single-component phosphor are very much essential. Green light emitting phosphors are widely used in solid state lighting technology. Tb3+ ions are doped into different hosts and they are excited by UV or NUV light to emit green light. This review presents, different hosts like silicates, oxides, phosphates and titanates based Tb3+ ions doped phosphor. Attempts were made to analyse preparation technique and photoluminescence characteristics of phosphors. Finally potential material among selected materials is identified for light emitting display device applications.
Optics & Laser Technology, 2015
A series of Eu 2 þ and Eu 2 þ /Tb 3 þ co-doped Ba 3 GdNa(PO 4) 3 F phosphors have been synthesized via a high temperature solid-state reaction. The relative intensity of PL spectra of Ba 3 GdNa(PO 4) 3 F:xEu 2 þ increases with increasing x value, and reaches a maximum at x ¼0.04. Ba 3 GdNa(PO 4) 3 F:Eu 2 þ , Tb 3 þ phosphors exhibit a broad excitation band ranging from 220 to 450 nm, which matches perfectly with the characteristic emission of n-UV light-emitting diode (LED) chips. Upon 365 nm excitation, the Ba 3 GdNa(PO 4) 3 F:Eu 2 þ , Tb 3 þ phosphors show two dominating bands peaked at 466 and 543 nm, which are assigned to the 4f 7-4f 6 5d 1 transition of the Eu 2 þ ions and the 5 D 4-7 F 5 transition of the Tb 3 þ ions, respectively. In view of the energy transfer mechanism between Eu 2 þ and Tb 3 þ , the Ba 3 GdNa(PO 4) 3 F:Eu 2 þ , Tb 3 þ emission color can adjust from blue to green, and their chromatic coordinates (x, y) vary from (0.16, 0.135) to (0.254, 0.398). The critical distance was also calculated to be 16.90 Å. The above results indicate that the Ba 3 GdNa(PO 4) 3 F: Eu 2 þ , Tb 3 þ phosphors are a candidate for bluegreen components in the application of n-UV w-LEDs.
Luminescence properties and energy transfer in Eu2+, Mn2+ codoped Na(Sr,Ba)PO4 phosphor
Applied Physics A, 2013
A series of Sm 3 þ /Eu 3 þ singly and co-doped Ba 2 Ln(BO 3) 2 Cl (Ln¼ Y 3 þ , Gd 3 þ) phosphors were prepared via the solid-state method. The XRD results indicate that the as-prepared products keep the monoclinic structure with a P 21/m space group of Ba 2 Ln(BO 3) 2 Cl, which belongs to the isomorphic substitution for Ln 3 þ sites in the Ba 2 Yb(BO 3) 2 Cl host. The photoluminescence (PL) spectra demonstrate that Ba 2 Ln (BO 3) 2 Cl:Sm 3 þ ,Eu 3 þ emits red light centered at 593 nm under the 393 nm excitation which is in good agreement with the emission wavelength from near ultraviolet light-emitting diodes (LEDs). The luminescence decays suggest that the energy transfer from Sm 3 þ to Eu 3 þ ions in Ba 2 Ln(BO 3) 2 Cl:Eu 3 þ , Sm 3 þ occurs. All results mean that Ba 2 Ln(BO 3) 2 Cl:Eu 3 þ , Sm 3 þ phosphors exhibit potential to act as a kind of red phosphor for near ultraviolet white light-emitting diodes (w-LEDs).
Inorganic Chemistry, 2013
Pure Ca2Ba3(PO4)3Cl and rare earth ion (Eu(2+)/Ce(3+)/Dy(3+)/Tb(3+)) doped Ca2Ba3(PO4)3Cl phosphors with the apatite structure have been prepared via a Pechini-type sol-gel process. X-ray diffraction (XRD) and structure refinement, photoluminescence (PL) spectra, cathodoluminescence (CL) spectra, absolute quantum yield, as well as lifetimes were utilized to characterize samples. Under UV light excitation, the undoped Ca2Ba3(PO4)3Cl sample shows broad band photoluminescence centered near 480 nm after being reduced due to the defect structure. Eu(2+) and Ce(3+) ion doped Ca2Ba3(PO4)3Cl samples also show broad 5d → 4f transitions with cyan and blue colors and higher quantum yields (72% for Ca2Ba3(PO4)3Cl:0.04Eu(2+); 67% for Ca2Ba3(PO4)3Cl:0.016Ce(3+)). For Dy(3+) and Tb(3+) doped Ca2Ba3(PO4)3Cl samples, they give strong line emissions coming from 4f → 4f transitions. Moreover, the Ce(3+) ion can transfer its energy to the Tb(3+) ion in the Ca2Ba3(PO4)3Cl host, and the energy transfer mechanism has been demonstrated to be a resonant type, via a dipole-quadrupole interaction. However, under the low voltage electron beam excitation, Tb(3+) ion doped Ca2Ba3(PO4)3Cl samples present different luminescence properties compared with their PL spectra, which is ascribed to the different excitation mechanism. On the basis of the good PL and CL properties of the Ca2Ba3(PO4)3Cl:A (A = Ce(3+)/Eu(2+)/Tb(3+)/Dy(3+)), Ca2Ba3(PO4)3Cl might be promising for application in solid state lighting and field-emission displays.
Journal of Materials Chemistry, 2012
Vacuum ultraviolet (VUV) spectroscopic properties of undoped and Tb 3+-doped Ba 3 Sc(BO 3) 3 were investigated by using synchrotron radiation. The Tb 3+-doped Ba 3 Sc(BO 3) 3 sample crystallized in a flower-like shape even was synthesized at 1100 C. Upon VUV excitation, Ba 3 Sc(BO 3) 3 exhibited an intrinsic broad UV emission centered at 336 nm, which results from radiative annihilation of selftrapped exciton (STE) that may presumably be associated with band-gap excitations or molecular transitions within the BO 3 3À group. The maximum host absorption for Ba 3 Sc(BO 3) 3 was found at about 180 nm. Upon doping of Tb 3+ ions into Ba 3 Sc(BO 3) 3 , an efficient energy transfer from the host excitations to Tb 3+ via STE emission was observed, showing host sensitization of Tb 3+ occurs. The energy transfer from host to Tb 3+ via STE emission in Ba 3 Sc(BO 3) 3 :Tb 3+ was studied as a function of temperature and Tb 3+ doping concentration. It has been demonstrated that the energy transfer efficiency was increased with either increasing temperature or Tb 3+ doping concentration. In the case of temperature dependent energy transfer, the energy transfer from the STE to Tb 3+ is thermally activated, probably due to exciton mobility, while in the case of concentration dependent energy transfer, the energy transfer from the STE to Tb 3+ is promoted due to a closer distance between the STE and Tb 3+ at high Tb 3+ concentration.
Efficient near-infrared quantum cutting in Tb3+,Yb3+ codoped LuPO4 phosphors
Journal of Rare Earths, 2017
Tb 3+ and Yb 3+ codoped LuPO 4 phosphors were prepared by the reverse-strike co-precipitation method. The obtained LuPO 4 :Tb 3+ ,Yb 3+ phosphors were characterized by X-ray diffraction (XRD), photoluminescence (PL) spectra and decay kinetics to understand the near-infrared quantum cutting (QC) phenomena. The XRD results showed that all the phosphors exhibited good crystallinity and had a pure tetragonal phase of LuPO 4. The experimental results showed that the strong green emission around 545 nm from Tb 3+ (5 D 4 → 7 F 5) and near-infrared (NIR) emission at 1003 nm from Yb 3+ (2 F 5/2 → 2 F 7/2) of LuPO 4 :Tb 3+ ,Yb 3+ phosphors were observed under 489 nm excitation, respectively. The Yb 3+ concentration dependence on luminescent properties and lifetimes of both the visible and NIR emissions were also investigated. The quenching concentration of Yb 3+ ions approached as high as 10 mol.%. The excellent luminescence properties of the LuPO 4 :Tb 3+ ,Yb 3+ indicated its potential application in improving the energy conversion efficiency of the silicon based solar cells by converting one blue photon to two NIR ones.
Efficient near-infrared quantum cutting by cooperative energy transfer in Bi3TeBO9:Nd3+ phosphors
Journal of Materials Science, 2022
An efficient near-infrared quantum cutting process by cooperative down-conversion of active Bi3+ and Nd3+ ions was demonstrated in Bi3TeBO9:Nd3+ phosphors. In particular, the near-infrared emission of Nd3+ ions enhanced by Bi3+ ions of a series of novel Bi3TeBO9:Nd3+ microcrystalline powders doped with Nd3+ ions in various concentrations was investigated. In order to investigate the luminescent properties of BTBO:Nd3+ powders, the excitation and emission spectra and the fluorescence decay time were measured and analyzed. In particular, the emission of Bi3TeBO9:Nd3+ at 890 and 1064 nm was excited at 327 nm (via energy transfer from Bi3+ ions) and at 586.4 nm (directly by Nd3+ ions). The highest intensity emission bands in near-infrared were detected in the spectra of Bi3TeBO9:Nd3+ doped with 5.0 and 0.5 at.% of Nd3+ ions upon excitation in ultraviolet and visible spectral range, respectively. The fluorescence decay lifetime monitored at 1064 nm for Bi3TeBO9:Nd3+ powders shows the sin...