Study on Luminescence Properties of High-Density Phosphors BiTaO4∶Pr3+ and BiTaO4

The photoluminescence properties of BiTaO4∶Pr3+ and BiTaO4 at room temperature were studied, and the infrared transmission and diffusion reflection spectra of BiTaO4 were measured. The photoluminescence spectrum of BiTaO4 peaks at about 420, 440 and 465 nm. There has an obvious excitation band from 330 to 370 nm. The photoluminescence spectrum of BiTaO4∶Pr3+ consists of the characteristic emission of Pr3+, and its main peak is at 606 nm from 3P0→3H6 transition of Pr3+. Its excitation spectrum consists of the wide band with maximum at 325 nm, the wide band in the range of 375～430 nm, and the characteristic excitation of Pr3+. The bands at 325 nm and 375～430 nm may be from the absorption of the charge transfer transition of the tantalate group and defect energy levels in its forbidden band, respectively. There is energy transfer from host to Pr3+. Because both the host density and photoluminescence peak intensity of BiTaO4∶Pr3+ are superior to PbWO4, BiTaO4∶Pr3+ may be a potential heavy scintillator.     

Luminescence Properties of Tb^3＋ -Doped LuAG Films Prepared by Pechini Sol-Gel Method

Lu3Al5O12（LuAG） thin films with different Tb^3＋ concentration were prepared on carefully cleaned （111 ） silicon wafer by a Peehini process and dip-coating technique. Heat treatment was performed in the temperature range from 800 to 1100 ℃. The crystal structure was analyzed by XRD. The results show that LuAG film starts to crystallize at about 900 ℃, and the particle size increases with the sintering temperature. Excitation and emission spectra of Tb^3＋ doped LuAG films were measured. The effects of heat-treatment temperature and doping concentration of Th3 ＋ on the luminescent properties were also investigated. For a comparison study, Th^3＋-doped LuAG powders were also prepared by the same sol-gel method.     

Luminescence and Defect Properties of Novel Bluish-Green Phosphor β-Zn3(PO4)2∶Zr4+

Luminescence and defect properties of novel phosphor β-Zn3(PO4)2:Zr4 were systematically investigated. Corresponding to its lowest optical absorption transition at 240 nm, phosphor emits a bluish-green light at 485 nm, which yields the Stokes shift about 20000 cm-1. The unusual optical properties of Zr4 ion are ascribed to its uncommon coordination environment. In addition it shows intensive bluish-green long lasting phosphorescence(LLP) due to the existence of electron trap, which is generated by aliovalent substitution of Zr4 ion for the cation site in the matrix as shown in thermoluminescence(TL) spectrum.     

Luminescence of Terbium Complexes Incorporated into Silica Matrix

Ｔｈｅｓｏｌ ｇｅｌｍｅｔｈｏｄｈａｓｓｈｏｗｎａｓｕｉｔａｂｌｅａｐｐｒｏａｃｈｆｏｒｔｈｅｐｒｅｐａｒａｔｉｏｎｏｆｎｏｖｅｌｌｕｍｉｎｅｓ ｃｅｎｔｍａｔｅｒｉａｌｓ .Ｍａｎｙｒｅｃｅｎｔｗｏｒｋｓｈａｖｅｆｏ ｃｕｓｅｄｏｎｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｓｏｌｉｄ ｓｔａｔｅｔｕｎａｂｌｅｄｙｅｌａｓｅｒｍｅｄｉａｕｓｉｎｇｏｒｇａｎｉｃｄｙｅｄｏｐａｎｔｓ[1 ,2 ]ａｎｄｔｒｉｓ( 2 ,2′ ｂｉｐｙｒｉｄｉｎｅ)ｒｕｔｈｅｎｉｕｍ (Ⅱ )ｃｏｍ ｐｌｅｘ[3 ,4 ] ｗｈｉｃｈｃａｎｈａｖｅｓｏｍｅｐｏ…     

Preparation and Luminescence Properties of the New Long Phosphorescent Phosphors Ba1-xCaxAl2O4∶Eu2+,Dy3+

New long phosphorescent phosphors Ba1-xCaxAl2O4∶Eu2 , Dy3 with tunable color emission were prepared and studied. The emission spectra show that the tuning range of the color emission of the phosphors is between 498 and 440 nm, which is dependent on x, under the excitation of UV. The wavelength of the afterglow increases with the increasing of x until x equals 0.6. The XRD patterns show that the single phase limit in the phosphors is below x value of 0.4. The Thermoluminescence spectra were measured to investigate the traps created by the doping of Dy3 .     

Displacement and Luminescence of Eu~(3 ) in CaYBO_4

Ａｇｒｅａｔｄｅａｌｏｆｉｎｖｅｓｔｉｇａｔｉｏｎｈａｓｂｅｅｎｃａｒ ｒｉｅｄｏｕｔｏｎｔｈｅｌｕｍｉｎｅｓｃｅｎｃｅｏｆＥｕ3 ｉｎｍａｎｙｈｏｓｔｓ,ｓｕｃｈａｓｔｈｅｃｏｍｍｅｒｃｉａｌｒｅｄｐｈｏｓｐｈｏｒＹ2 Ｏ3∶Ｅｕ ,ｗｈｏｓｅｌｕｍｉｎｅｓｃｅｎｔｑｕａｎｔｕｍｅｆｆｉ ｃｉｅｎｃｙｈａｓａｔｔａｉｎｅｄｎｅａｒｌｙ 1 0 0 %ｕｎｄｅｒ 2 5 4ｎｍｅｘｃｉｔａｔｉｏｎ .Ｉｔｉｓａｌｓｏｔｈｅｈｉｇｈｅｓｔｑｕａｎｔｕｍｅｆｆｉ ｃｉｅｎｃｙｏｆａｌｌｔｈｅｃｏｍｍｅｒｃｉａｌｐｈｏｓｐｈｏ…     

Synthesis and Luminescence Properties of Gd_2O_3∶Eu~(3+) Phosphors

Gd2 O3∶Eu3+ isanefficientredemittinglumines centmaterial ,whichcanbeappliedindisplays[1,2 ] .TheconventionalcommercialGd2 O3∶Eu3+ ismainlysynthesizedbyhightemperaturesolid statereactionandchemicalco precipitationmethods .Anadvancedperformanceofdisplaysrequireshighqualityphospho rssuchashighbrightnessandefficiency ,monodisper sityandfinegrainsize .Muchresearchhasanticipatedthatsubmicrometer sizedandnanometerluminescentmaterialswillhavethesepotentialadvantages[3～ 8] ,sosubmicrometer sizedan…     

Luminescence properties of polymers containing europium complexes with 4-tert-butylbenzoic acid

The binary europium complex EuL3 (L=4-tert-butylbenzoate) and ternary europium complexes EuL3TTA0.1 (TTA=2-thenoyltrifluoroacetone), EuL3DBM0.5 (DBM=dibenzoylmethane) and EuL3phen0.5 (phen=1, 10-phenan...     

Er~(3 ) Doped BaTiO_3 Optical-Waveguide Thin Films Elaborated by Sol-Gel Method

Bariumtitanate (BaTiO3)isawell knownferro electricmaterial.Comparedtootherferroelectricma terials,suchasLiNbO3,BaTiO3hasmanyadvancedproperties ,forexamplehighelectro opticalindex (r= 82 0pm·V- 1,6 32 8nm ,higherthan 30 8pm·V- 1at 6 32 8nmofLiNbO3) ,lowhalf wavevolt age (310Vat 6 32 8nm ,lowerthan 2 94 0Vat 6 32 8ofLiNbO3) [1] ,lowpropagatinglossofopticalwave(≤ 4± 2dB·cm- 1) [2 ] andconvenientdopingofrare earthions ,whichisnecessaryforopticallyactivede vices .RecentlyBaTiO3fi…     

Organic Light Emitting Devices Based on Terbium Complex

Rare earth complex TbY(m-MOBA)6(phen)2·2H2O was synthesized,which was first used as an emitting material in electroluminescence.The properties of monolayer device with the rate of 1000 r·min-1 (70 nm) and the impure concentration of 1∶5 were the best.And the highest brightness of this device reached 21.8 cd·cm-2 at a fixed bias of 20 V.Bright green emission can be obtained from the optimized double-layer device,and the highest EL brightness of the device reached 289 cd·m-2 at the voltage of 21 V.     

Luminescence of Terbium Chelates with Substituted Pyridine-2, 6-Dicarboxylic Acid Derivatives by Synergistic Effect of EDTA

Luminescence of Terbium Chelates with Substituted Pyridine-2, 6-Dicarboxylic Acid Derivatives by Synergistic Effect of EDTA     

Upconversion Luminescence of YLiF4 :Er3+ Synthesized by Hydrothermal Method

YLiF4: Er3 was synthesized by hydrothermal method. Concentration of Er3 is changed from 0 to 5 %. The absorption of Er3 in all samples from 200 to 1200 nm was measured at room temperature. The J-O parameters calculated from absorption spectrum areΩ 2 = 1.05 × 10- 20 cm2, Ω4 = 1.25 × 10- 20 cm2 andΩ6 = 1.35 × 10- 20 cm2. Infrared-to-visible upconversion emission of YLiF4: Er3 was observed when excited by 980 nm. The results show that the Er3 content is less than 1.5 %, excite-state absorption is the main mechanism of upconversion emission. When Er3 content is larger than 1.5 %, both of the excite-state absorption and energy transfer lead to the upconversion luminescence. The upconversion intensity was enhanced with the increasing of Er3 concentration. At room temperature, the lifetime of 2H11/2 and 4S3/2is 205μs while that of 4F9/2 is 188μs for sample Er-2. The transition rates and quantum efficiency were also calculated.The quantum efficiencies of 4S3/2 and 4F9/2 are 27.9% and 10.7%, respectively.     

Fabrication and Luminescence of Rare Earth Complex／SiO2 Hybrid Nanospheres

The organic rare earth complex was embedded in silica spheres to form inorganic-organic hybrid. Photoactiver are earth complexes with various organic ligands exhibit intense narrow emission band, and the silica is an excellent matrix for inorganic-organic structure. The transmission electron microscope image presents the hybrid nanospheres. The diameter of the hybrid is about 100 nm. The europium complex that incorporated into silica sphere is also proved by the IR spectra, the excitation and emission spectra. The lifetimes of the Eu3 ions in the hybrid nanospheres and in the pure europium complex were also detected. This hybrid with inhomogeneous compositions exhibits specifically tailored chemical and optical properties, such as perfect thermal and mechanical stability, colorimetric purity and so on. It can be used as luminescent and optical material in EL and PL fields.     

Synthesis, Characterization and Fluorescence Properties of Europium, Terbium Complexes with Biphenyl-4-Carboxylic Acid and o-Phenanthroline

Two series of solid complexes of europium and terbium with biphenyl 4-carboxylic acid and phen were synthesized and characterized in this report. Their elemental analysis, molar conductivities and TG-DTA studies indicate that the complexes have the composition of Eu(phen)L3·1/2H2O, Eu0.5RE0.5(phen)L3·1/2H2O; Tb(phen)L3·H2O and Tb0.5RE0.5(Phen)L3·1/2H2O. (RE=Y3 , La3 and Gd3 ; L=biphenyl 4-carboxylic acid; phen=o-Phenanthroline). The studies of their IR, UV 1H NMR and molar conductivities demonstrate that biphenyl 4-carboylic acid is bounded with RE(Ⅲ) ion. Rare earth ions coordinate with two nitrogen atoms of phen molecules directly in these rare earth complexes. The fluorescence spectra and fluorescence lifetimes of the rare earth complexes show that the fluorescent intensity and lifetime of a series of europium complexes are longer than those of the series of terbium complexes as having the some ligands. There are better fluorescent intensity and lifetime of hetero-nuclear rare earth complexes than homo-nuclear rare earth complexes for europium complexes. The fluorescence emission intensity of Eu3 is raised by inert fluorescent rare earth ions (Y3 , Gd3 and La3 ), but in Tb3 hetero-nuclear rare earth complexes the intensity of Tb3 ions are quenched by the inert fluorescent rare earth ions.     

Luminescence Properties of Green-Emitting Phosphor (Ba1-x,Srx)2SiO4:Eu2+ for White LEDS

The (Ba1-xSrx)2SiO4∶Eu2 green-emitting phosphors were synthesized by conventional solid-state reaction in a CO-reductive atmosphere, and their luminescent properties were investigated. The XRD data show that the Ba/Sr ratio not only affects the lattice parameters, but also influences the emission peak. The excitation spectra indicate that this phosphor can be effectively excited by UV light from 370 to 470 nm. The emission band is due to the 4f65d1→4f7 transition of the Eu2 ion. With an increase in x, the emission band shifts to longer wavelength and the reason was discussed. The emission spectra exhibit a satisfactory green performance under different excitation wavelength(380, 398, 412, 420, 460 nm). (Ba1-xSrx)2SiO4∶Eu2 is a promising phosphor for green white-lighting-emission diode by ultraviolet chip.     

Sol-Gel Assembly and Luminescence of SiO2／PEMA Hybrid Material Incorporated with Terbium Complex

Ｔｈｅｓｏｌ ｇｅｌｍｅｔｈｏｄｈａｓｂｅｅｎｓｈｏｗｎｔｏｂｅａｓｕｉｔａｂｌｅａｐｐｒｏａｃｈｆｏｒｔｈｅａｓｓｅｍｂｌｙｏｆｎｏｖｅｌｌｕｍｉｎｅｓｃｅｎｔｍａｔｅｒｉａｌｓ[1 ,2 ] .Ｐｈｏｔｏａｃｔｉｖｅｒａｒｅｅａｒｔｈｏｒｇａｎｉｃｃｏｏｒｄｉｎａｔｉｏｎｃｏｍｐｏｕｎｄｓ ,ｓｕｃｈａｓｅｕｒｏｐｉｕｍａｎｄｔｅｒｂｉｕｍｃｈｅｌａｔｅｓｗｉｔｈｏｒｇａｎｉｃｌｉｇａｎｄｓｅｘｈｉｂｉｔｉｎｔｅｎｓｅｎａｒｒｏｗｂａｎｄｅｍｉｓｓｉｏｎｓｖｉａａｎｅｆｆｅｃｔｉｖｅｅｎｅｒｇｙｔｒａｎ…     

Preparation,Structural Analysis and Luminescence Properties of Nanocrystalline Phosphor Gd2O3∶Eu

Nanocrystalline monoclinic and cubic Gd2O3∶Eu with different Eu3 concentration were prepared using glycine-nitrate combustion synthesis. By changing the ratio of glycine to nitrate and proper heat treatment, pure monoclinic and cubic Gd2O3∶Eu with particle size less than 40 nm can be easily formed. Under ultraviolet excitation, main emission of Eu3 (5D0→7F2) locates at 624 nm in monoclinic Gd2O3∶Eu and 611 nm in cubic sample. In excitation spectrum two broad bands corresponding to the host absorption and charge transfer state(CTS) and f-f transitions of Gd3 and Eu3 were observed and discussed. The quenching concentration of monoclinic and cubic Gd2O3∶Eu is 10% and 15%, respectively, both of which are much higher than that of bulk Gd2O3∶Eu.     

Study on Luminescence Properties and Crystal-Lattice Environment of Eu~(2 ) in Sr_(4-x)Mg_x Si_3O_8Cl_4∶Eu~(2 ) Phosphor

ChlorosilicatecrystalmaterialM4 Si3O8Cl4 (M =Ba ,Sr ,Ca)isasuitablehostlatticeforluminescencematerials .Adivalenteuropiumactivatedstrontiumchlorosilicatephosphorisakindofgoodblue greenemissionphotoluminescencematerialunderUVexcita tion .Itsluminescencepropertiesandcrystalstructurehavebeenintensivelystudied[1～4 ] .Inthechlorosili catehost ,theluminescenceofEu2 consistsofa4f6 5d1- 4f7(8S7/2 )broad bandemission ,whichbe longstoelectric dipoleallowedtransitionandhasthepropertiesoflargeabso…     

Citrate-Gel Synthesis and Luminescent Properties of α-Zn3(PO4)2 Doped with Eu3+

By using inorganic salts as raw materials and citric acid as complexing agent, α-Zn3(PO4)2 and Eu3 doped α-Zn3(PO4)2 phosphor powders were prepared by a citrate-gel process. X-ray diffraction(XRD), TG-DTA, FT-IR and luminescence excitation and emission spectra were used to characterize the resulting products. The results of XRD reveal that the powders begin to crystallize at 500 ℃ and pure α-Zn3(PO4)2 phase is obtained at 800 ℃. And the results of XRD reveal that Eu3 exists as EuPO4 in the powder. In the phosphor powders, the Eu3 shows its characteristic red-orange(592 nm, 5D0-7F1) emission and has no quenching concentration.     

Luminescence Properties of Rare Earth Ions in Cadmium Metasilicate

The luminescence properties of CdSiO3:RE^3 phosphors doped with various rare earth ions are reported. The series of rare earth ions doped CdSiO3 phosphors are prepared by the conventional high-temperature solid-state method, and characterized by XRD and photoluminescence (PL) spectra. The results of XRD measurement indicate that the products fired under 1050 ~C for 3 h have a good crystallization without any detectable amount of impure phase. The PL spectra measurement results show that CdSiO3 is a novel self-activated luminescent matrix. When rare earth ions such as Y^3 ,La^3 , Gd^3 , Lu^3 , Ce^3 , Nd^3 , Ho^3 , Er^3 , Tm^3 and Yb^3 are introduced into the CdSiO3 host, one broadband centered at about 420 nm resulted from traps can be observed. In the case of other earth ions which show emissions at the visible spectrum region, such as Pr^3 , Sm^3 , Eu^3 , Tb^3 and Dy3 , the mixture of their characteristic line emissions with the ～420 nm strong broadband luminescence results in various emitting colors. As a consequence, different emitting colors can be attairied via introducing certain appropriate active ions into the CdSiO3 matrix. In additional, this kind of phosphors shows good long-lasting properties when excited by UV light. All the results show that CdSiO3 is a potential luminance matrix.