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1.
The Dy3+-doped NaY(MoO4)2 single crystals were grown successfully by the Czochralski technique. The main spectroscopic properties (absorption, luminescence, decay curve) of Dy3+-doped NaY(MoO4)2 have been determined for both the σ and π polarizations. By using the Judd-Ofelt theory, the measured room temperature absorption spectra were applied to determine the intensity parameters, spontaneous transition probabilities, branching ratios, and radiative lifetimes of Dy3+ transitions. The results show that the Dy3+-doped NaY(MoO4)2 crystal may realize the yellow laser operation. 相似文献
2.
Xin Wang 《Journal of luminescence》2011,131(8):1719-1723
Photoluminescence of Eu(TTA)3DPBT (TTA=thenoyltrifluoro-acetonate DPBT=2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine) in toluene and PMMA thin film are measured with excitation at 350 and 404 nm, respectively, and analyzed using Judd-Ofelt theory. Under excitation at 350 nm, it is found that Eu(TTA)3DPBT in toluene has a larger Ω2 value (14.33×10−20 cm2) than that (12.70×10−20 cm2) of Eu(TTA)3Phen (Phen=1,10-phenanthroline) in the same solvent, and has a smaller Ω2 value (12.70×10−20 cm2) in PMMA than that (Ω2=14.09×10−20 cm2) of Eu(TTA)3Phen in PMMA. At the same time, it can be seen that under excitation at 350 nm Ω2 value of Eu(TTA)3DPBT in toluene is larger than that in PMMA. Excited by 404 nm, Ω2 of Eu(TTA)3DPBT obtained in toluene and in PMMA are the same as that excited at 350 nm. The transition probability (A), emission cross-section (σ) and the fluorescence branching ratio (β) are also evaluated. The lifetime of 5D0 metastable state is measured on 350 and 404 nm excitation, respectively. For the former situation, it is 455 μs in toluene and 640 μs in PMMA, for the latter it is 460 μs in toluene and 664 μs in PMMA. By comparing absorptions with excitations, it can be found that DPBT is more efficient than TTA as an energy donor. Phosphorescence spectra are also measured to estimate the lowest triplet level and analyze the energy transfer for DPBT and TTA, from which it is found that the energy transfer from TTA to DPBT occurs in the luminescent process. 相似文献
3.
Eu3+-doped LiGd(MoO4)2 red phosphor was synthesized by solid-state reaction, and its photoluminescent properties were measured. The effect of Eu3+ doping concentration on PL intensity was investigated, and the optimum concentration of Eu3+ doped in LiGd(MoO4)2 was found to be 30 mol%. Compared with Y2O2S:0.05Eu3+, Na0.5Gd0.5MoO4:Eu3+ and KGd(MoO4)2:Eu3+, the LiGd(MoO4)2:Eu3+ phosphor showed a stronger excitation band around 395 nm and a higher intensity red emission of Eu3+ under 395 nm light excitation. For the first time, intensive red light-emitting diodes (LEDs) were fabricated by combining phosphor and a 395 nm InGaN chip, confirming that the LiGd(MoO4)2:Eu3+ phosphor is a good candidate for LED applications. 相似文献
4.
Linghong Yi Liya Zhou Zhengliang Wang Jianhua Sun Fuzhong Gong Weiping Wan Wei Wang 《Current Applied Physics》2010,10(1):208-213
A red phosphor KGd(MoO4)2:Eu3+ was prepared by solid-state reaction technique at high temperature. Its photoluminescent property was investigated and the optimum concentration of Eu3+ doped in the KGd(MoO4)2 is 25 mol%. Compared with Y2O2S:0.05Eu3+, the obtained KGd(MoO4)2:Eu3+ shows wider excitation band around 400 nm, higher intensity of Eu3+ 5D0–7F2 emission upon excitation 393 nm, and the CIE chromaticity coordinates (x = 0.655, y = 0.345) are closer to the standard of National Television Standard Committee (NTSC). The optical properties of KGd(MoO4)2:Eu3+ suggest that it is an efficient red-emitting phosphor for light-emitting diode applications. 相似文献
5.
Two europium complexes, Eu(DBM)3(PBO) and Eu(DBM)3(PBT) (DBM=dibenzoylmethanato, PBO=2-(2-pyridyl)benzoxazole, PBT=2-(2-pyridyl)benzothiazole), were prepared and used as emitting materials in organic electroluminescent (EL) devices. The devices with the structures ITO/TPD/Eu(DBM)3(PBO) (or Eu(DBM)3(PBT)/BCP/Alq3/Mg:Ag/Ag emit red light originating from the europium complexes. 相似文献
6.
Single crystals of KGd(WO4)2 doped with Nd3+ and Er3+ ions were grown by the top seeded solution growth method. Detailed analysis of the room-temperature absorption spectra was performed using the conventional Judd-Ofelt theory and actual dependence of the refractive index on the wavelength. In addition to the intensity parameters Ω2,Ω4,Ω6, the branching ratios and radiative lifetimes were estimated for all possible transitions in the studied spectral region. Those transitions which can be potentially used for laser applications have been identified for both ions. 相似文献
7.
A blue emitting phosphor of the triclinic BaCa2Si3O9:Eu2+ was prepared by the combustion-assisted synthesis method and an efficient blue emission ranging from the ultraviolet to visible was observed. The luminescence and crystallinity were investigated using luminescence spectrometry and X-ray diffractometry (XRD), respectively. The emission spectrum shows a single intensive band centered at 445 nm, which corresponds to the 4f65d1→4f7 transition of Eu2+. The excitation spectrum is a broad extending from 260 to 450 nm, which matches the emission of ultraviolet light-emitting diodes (UV-LEDs). The critical quenching concentration of Eu2+ in BaCa2Si3O9:Eu2+ phosphor is about 0.05 mol. The corresponding concentration quenching mechanism is verified to be a dipole-dipole interaction. The CIE of the optimized sample Ba0.95Ca2Si3O9:Eu0.052+ was (x, y)=(0.164, 0.111). The result indicates that BaCa2Si3O9:Eu2+ can be potentially useful as a UV radiation-converting phosphor for white light-emitting diodes (LEDs). 相似文献
8.
利用X射线粉末衍射确定了Tm3+掺杂硅酸镓镧(La3Ga5SiO14,LGS)晶体的晶体结构;运用DICVOL91程序计算了该晶体不同部位的晶胞参数;测定了Tm:LGS晶体的室温吸收谱和470nm光激发下的发射光谱;根据Judd-Ofelt理论拟合了Tm3+的三个晶场调节参数Ωt(t=2,4,6),分别为2.694×10-20cm2,1.842×10-20cm2,0.030×10-20cm2;计算了各个能级跃迁的谱线强度、振子强度、吸收截面等,进而计算了3H4和3F4态的自发跃迁概率、辐射寿命、荧光分支比和积分发射截面,并对结果进行了分析.
关键词:
Tm:LGS晶体
吸收谱
Judd-Ofelt理论
光谱参数 相似文献
9.
Xinmin ZhangHyo Jin Seo 《Physica B: Condensed Matter》2011,406(1):77-79
Novel Eu3+, Ce3+ activated NaBa4(BO3)3 phosphors were synthesized by solid-state reactions. The excitation spectrum of NaBa4(BO3)3:Ce3+ consists of an intense band peaking at 350 nm and a weak band in the higher energy side, and the emission spectrum exhibits a blue band with a maximum at about 420 nm. The Eu3+ emission in NaBa4(BO3)3 consists of the transitions from 5D0 to 7FJ, and the excitation spectrum consists of broad excitation band peaking at 270 nm and some intense narrow lines. The optimum doped concentration, the critical distance of the concentration quenching, and the fluorescence lifetime have also been investigated. 相似文献
10.
The MgO-Ga2O3-SiO2 glass-ceramic (GC) containing MgGa2O4 nanocrystals and glasses doped with Eu3+ ions were prepared by the sol-gel method. The down-conversion and up-conversion luminescence (UCL) properties were studied. The results indicated that the relative intensity of f-f transitions of Eu3+ decreased in contrast with that of charge transfer (CT) absorption with the increase in heating temperature. Using a Xe lamp and 800 nm femtosecond (fs) laser excitation, strong red luminescence of Eu3+ in MgO-Ga2O3-SiO2 glasses and GC was observed. 相似文献
11.
Hong-Wei Li 《Optics Communications》2009,282(8):1579-1093
Erbium-doped MoO3−Bi2O3−TeO2 (MBT) glasses suitable for broadband optical amplifier applications have been fabricated and characterized optically. The maximum phonon band of undoped glasses is at 915 cm−1, and the emission from the Er3+: 4I13/2 → 4I15/2 transition locates around 1.53 μm with a full width at half maximum (FWHM) of ∼80 nm. The lifetime and quantum efficiency of the 4I13/2 level are 2.13 ms and ∼90%, respectively. Under the same measurement condition, the upconversion emission intensities at 550 nm in Er3+-doped MBT glasses is about 30 times weaker than that in Er3+-doped Na2O−ZnO−TeO2 (NZT) glasses. 相似文献
12.
Effects of WO3 and CdO on the spectroscopic properties of Nd3+ doped tellurite glasses were investigated. The optical band gaps and Urbach energies of the samples were determined using the dependence of the absorption coefficient on the photon energy. The Urbach energies were found to vary from 0.18 to 0.25 eV as the WO3 content in the binary glasses decreased from 20.0 to 10.0 mol% while the optical band gap of the same glasses did not show an appreciable dependence on the glass composition. Judd-Ofelt (Ωt) parameters were calculated from the optical absorption spectra measured at room temperature. In all the glasses the J-O parameters follow the same trend as Ω2>Ω6>Ω4. The J-O intensity parameters were used to compute the radiative properties such as the radiative transition probabilities (Aed), branching ratios (β) and radiative lifetimes (τr) for all the possible fluorescence bands. The fluorescence spectra obtained upon 805.2 nm excitation exhibited an intense emission band centered at 1064 nm (4F3/2→4I11/2) and two weak bands at 910 nm (4F3/2→4I9/2), and 1340 nm (4F3/2→4I13/2). The stimulated emission cross-section for the 1064 nm emission was determined using the emission spectra. The highest gain bandwidth (σe×ΔλP) was determined to be 155.4 for the 0.79TeO2-0.15WO3-0.05CdO ternary glass composition, which could be more useful as promising material for the design and development of fiber amplifiers and lasers. 相似文献
13.
A. Kato S. Iida M. Yamazaki C. Hidaka 《Journal of Physics and Chemistry of Solids》2005,66(11):2076-2078
Room temperature photoluminescence quantum efficiency of the alloy of Ca1−xEuxGa2S4 was measured as a function of x, and was found to be nearly unity under excitation at peak wavelength of excitation spectrum (510 nm) in the x range of 0.01≤x≤0.2. At larger x values, it tends to decrease, but still as high as 30% for stoichiometric compound EuGa2S4. Taking these backgrounds into account, pump-probe experiments were done with Ca1−xEuxGa2S4 for searching optical gain at x=0.2. The optical gain of nearly 30 cm−1 was confirmed to exist, though the pumping induced transient absorption which seems to limit the higher gain was found. 相似文献
14.
Z.X. Cheng S.J. ZhangF. Song H.C. GuoJ.R. Han H.C. Chen 《Journal of Physics and Chemistry of Solids》2002,63(11):2011-2017
Erbium and ytterbium codoped double tungstates NaY(WO4)2 crystals were prepared by using Czochralski (CZ) pulling method. The absorption spectra in the region 290-2000 nm have been recorded at room temperature. The Judd-Ofelt theory was applied to the measured values of absorption line strengths to evaluate the spontaneous emission probabilities and stimulated emission cross sections of Er3+ ions in NaY(WO4)2 crystals. Intensive green and red lights were measured when the sample were pumped by a 974 nm laser diode (LD), especially, the intensities of green upconversion luminescence are very strong. The mechanism of energy transfer from Yb3+ to Er3+ ions was analyzed. Energy transfer and nonradiative relaxation played an important role in the upconversion process. Photoexcited luminescence experiments are also fulfilled to help analyzing the transit processes of the energy levels. 相似文献
15.
V.I. Gerasimova Yu.S. Zavorotny A.Yu. Chebrova D.A. Lemenovskii 《Journal of luminescence》2009,129(10):1115-1119
X-ray diffraction pattern of solvated Eu(fod)3(H2O)1,5(i-PrOH)0,5 form of Eu(fod)3 complex (fod=6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) is presented. The photoluminescence (PL) spectra of Eu3+ ions in polycrystalline powder Eu(fod)3 and also in Eu(fod)3-doped polymethylmethacrylate (PMMA), polypropylene (PP) and polydimethylsiloxane (PDMS) were investigated. It is revealed that the matrix influences the temperature quenching of PL intensity in the range 20-100 °C. A polycrystalline powder Eu(fod)3 and Eu(fod)3-doped PP are the most effective materials for PL quenching. It is shown that water molecules in the first coordinating sphere of Eu3+ ions increase PL intensity temperature quenching. 相似文献
16.
17.
合成了稀土配合物Eu(TTFA)3(TTFA,2-thenoyltfifluoroacetone)掺杂的树脂型光刻胶薄膜,测定了薄膜的激发光谱和发射光谱.根据Judd-Ofelt理论,由发射光谱获得了Eu3+在光刻胶薄膜中的J-O参数Ω2=24.4×10-20cm2,Ω4=2.8×10-20cm2.利用得到的J-O参数计算了光刻胶薄膜中5D0激发态的辐射跃迁概率(977 s-1)和辐射寿命(1.02 ms),同时导出了光刻胶薄膜中Eu3+的5D0→FJ(J=1,2,4)跃迁的受激发射截面σ和荧光分支比β.分析表明,Eu3+掺杂的光刻胶薄膜具有较长的亚稳态寿命以及较大的受激发射截面,是一种主动放大的光波导薄膜.其发射波长与光刻胶的低吸收损耗区很好地匹配,可用于研发聚合物光波导放大器和激光器. 相似文献
18.
Optical properties of near-stoichiometric compositions of Ba3B′B″2O9 (B′=Mg, Co or Zn and B″=Nb or Ta) perovskite type materials were studied by means of photoluminescence (PL) spectroscopy. Ba3B′B″2O9 perovskites belong to the family of perovskite materials that exhibit phase transition from a completely disordered system having space group Pm-3m to a 1:2 ordered one with space group P-3m1. As revealed by X-ray diffraction, deviation from stoichiometry results in the formation of Ba- and Nb-rich phases. Photoluminescence measurements demonstrated the presence of two broad peaks, the position of which depends on secondary phase formation: the first one, attributed to the disordered Pm-3m phase, is positioned at approximately 430 nm and the second band, positioned at lower energies (i.e., longer wavelengths, around 900 nm), was ascribed to the formation of the 1:2 ordered P-3m1 phase. The position of the first peak is influenced by the bond network through distortions in the local environment caused by the specific electronic structure of the B′ cation. 相似文献
19.
透明光学树脂中Eu3+辐射参数的理论和实验研究 总被引:3,自引:1,他引:2
报道了一种新合成的含三元稀土配合物的透明光学树脂材料的辐射特性的研究。基于J-O参数理论,利用含稀土配合物Eu(TTA)3phen-0.31wt%的光学树脂的发射荧光光谱,计算了Eu3 在光学树脂基质中的J-O参数Ω2=10.139 4×10-20cm2,Ω4=3.810 9×10-20cm2,Ω6=9.050 7×10-20cm2。利用得到的J-O参数可以计算光学树脂中Eu3 的跃迁振子强度fcal,5D0激发态的辐射跃迁概率A(456.6 s-1)、辐射寿命τ(2 190.1μs),还计算了光学树脂中Eu3 的跃迁5D0→7FJ′(其中J′=1,2,4,6)的发射截面σ、荧光分支比β。通过分析计算得到的J-O参数可知,光学树脂中Eu3 的5D0亚稳态的寿命较长,跃迁5D0→7F2的发射截面最大,说明含稀土配合物的光学树脂具有作光放大或激光材料的潜在性。 相似文献
20.
This paper describes the synthesis and characterization of self-assembled organic-inorganic layered perovskite compounds, (C6H5-CnH2n-NH3)2PbBr4 (n=1-4). the effect of the number of carbon atoms of the alkyl chain length (n) on optical properties has been studied. (C6H5-CnH2n-NH3)2PbBr4 films fabricated by spin-coating are microcrystalline form, single phase and oriented with the c-axis. Crystallinity, the maximum PL intensity and the lifetime of exciton emissions varied with the number of carbon atoms. the lowest-energy exciton splits into a few fine-structure levels at low temperatures. Time-resolved photoluminescence spectra reveal that (C6H5-CnH2n-NH3)2PbBr4 shows both singlet and triplet excitons. with decreasing temperature, triplet exciton emissions become dominant for (C6H5-CnH2n-NH3)2PbBr4 (n=1-3), while (C6H5-C4H8-NH3)2PbBr4 shows mainly singlet exciton emissions. The intersystem crossing from excited singlet state to triplet state plays an important role in the relaxation process of excitons. 相似文献