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1.
The photoluminescence and excitation spectra of Pr3+ activated LiLaP4O12 has been investigated in the 10-300 K temperature region. At all temperatures, the luminescence consists of optical transitions emanating from both the Pr3+ 4f15d1 and the 1S0 states. However, at low temperatures the emission spectrum is dominated by the intraconfiguration emission transitions emanating from the Pr3+1S0 state. With increasing temperature, there is an exchange of intensity between the two emitting states; emission transitions from the 1S0 state exhibit strong intensity quenching while the 4f15d1→4f2 emission transitions reveal intensity gain. These results are explained on the basis of thermal population of the 4f15d1 state by the 1S0 state. The energy barrier of 0.05 eV (403 cm−1) for the nonradiative process is determined from the temperature dependence of the 1S0 lifetime. 相似文献
2.
Spectroscopic investigations were performed on a single crystal of CaF2 doped with 0.05% Pr3+. Three different Pr3+ sites with different luminescent properties were identified. The 4f2 →4f15d1 excitation spectrum of the first site has a sharp maximum at 221.3 nm. Excitation in the 4f5d bands of this site yields strong 4f5d emissions in the UV/VIS part of the spectrum and also weaker intraconfigurational 4f2 emissions. By comparing the intraconfigurational 4f emissions and their decay times with data from the literature, these 4f5d bands are assigned to transitions on Pr3+ ions on a site with C4V symmetry. The fd excitation spectrum of the second site has a zero phonon line at 223.3 nm. Upon selective excitation in this band, only 4f5d emission is observed. Probably, these 4f5d bands correspond to Pr3+ ions on a Oh site. The third set of 4f5d bands has a 4f5d onset at 208 nm. By comparison of the luminescence spectra of the intraconfigurational 4f2 transitions with literature data, these transitions are assigned to Pr3+ on an L site. Excitation in these 4f5d band yields 1S0 emission followed by emission from the 3P0 state. The present results clarify some contradictions reported in the literature. 相似文献
3.
In this contribution, photoluminescence and time-resolved photoluminescence spectra of Ca(NbO3)2 doped with Pr3+ obtained at high hydrostatic pressure up to 72 kbar applied in a diamond anvil cell are presented. At ambient conditions, the emission spectrum obtained in the time interval 0-1 μs is dominated by spin-allowed transitions from the 3P0 state. On the other hand, transitions from 1D2, characterized by a decay time equal to 30 μs dominate the steady-state luminescence.At pressures lower than 60 kbar, the continuous wave emission spectrum consists of sharp lines peaking between 600 and 625 nm, related to the 1D2→3H4 transition and three lines at 500, 550 and 650 nm related to emission transitions originating from the 3P0 level of Pr3+. The emission from the 1D2 excited state depends weakly on the pressure. Its decay time decreases from 33 μs at ambient pressure to less than 22 μs at 68 kbar. On the other hand, the 3P0 emission is strongly pressure dependent. At pressures of 60 kbar and higher, the Pr3+ emission intensity from the 3P0 state decreases. This is accompanied by a strong shortening of the luminescence decay time.The observed pressure quenching of the f-f emission transitions and the concomitant lifetime shortening have been attributed to increasing crossover from the 3P0 state of Pr3+ to a Pr3+-trapped exciton state. 相似文献
4.
The spectral and kinetic parameters of LiCaAlF6:Pr and LiSrAlF6:Pr single crystals are studied at LHeT and room temperature (RT). Photon cascade emission (PCE), i.e., 1S0→1I6 and 3P0→3Hj, 3Fj transitions after Pr3+ excitation via 4f2→4f 5d absorption results in the conversion of the vacuum ultraviolet photon to two visible photons. The excitation and photoemission spectra as well as decay times have been measured and compared with those for CaF2:Pr and SrF2:Pr crystals. X-ray luminescence was measured to study the emission origin from both 1S0 and 3P0 states of Pr3+. An intense phosphorescence of LiSrAlF6:Pr was observed in the visible range after X-irradiation at RT, contrary to LiCaAlF6:Pr. 相似文献
5.
Weijie Guo Yanfu Lin Yujin Chen Yidong Huang 《Journal of Physics and Chemistry of Solids》2008,69(1):8-15
A Pr3+-doped KY(MoO4)2 single crystal was grown by the Czochralski method. The polarized absorption and fluorescence spectra of the Pr3+:KY(MoO4)2 crystal were measured at room temperature. The stimulated emission cross-sections for the transitions from the 3P0 multiplet were estimated from the fluorescence spectra. The fluorescence lifetime of the 3P0 multiplet was estimated from the fluorescence decay curve at room temperature. The analysis of spectral properties shows that the Pr3+:KY(MoO4)2 crystal is a promising gain medium for visible lasers. 相似文献
6.
用共沉淀法制备出不同掺杂浓度的钇铝石榴石(Y3Al5O12,YAG):Pr3+粉末.在不同温度下用同步辐射的真空紫外光(VUV)作为激发光 源测量了其发射和激发光谱.对YAG:Pr3+被VUV激发后的发光过程进行了分析, 并估算了YAG:Pr3+的声子能量、黄昆因子S及Stokes位移.当用170nm光激发样 品时,可能存在自陷激子和通过自陷激子能量传递引发的3P0发射 ,这种跃迁途径不同于用240nm和289nm两个波长激发后的跃迁途径;对Pr3+在Y AG中的4f5d能级进行了研究,从而对其4f5d组态有了一个较清晰的认识.
关键词:
3+')" href="#">YAG:Pr3+
同步辐射
4f5d能级
VUV 相似文献
7.
Yu-Chun Li Yu-Feng Lin Yi-Jing Lin 《Journal of Physics and Chemistry of Solids》2007,68(10):1940-1945
The luminescent characteristics of Pr3+-activated LaAlGe2O7 were investigated. In response to excitement using 448 nm blue light, the emission spectra involved most of the 3P0→3HJ transitions. The dominant emission came from the 3P0→3H4 transition at 487 nm. 1D2 fluorescence quenching was observed in highly doped samples and is related to the cross-relaxation processes among neighboring Pr3+ ions. In contrast with conventional Pr3+-activated phosphors, the extraordinary excitation spectra showed only intense f-f transition of Pr3+ ions, while the 4f-5d transition was eliminated. This is ascribed to photoionization. By analyzing absorption and excitation spectra, it is recognized that no efficient energy transfer occurs between Pr3+ and the host lattice in LaAlGe2O7. 相似文献
8.
The strong dependence of the emission spectrum of YF3:Pr3+ on excitation source (228.8 nm, 213.9 nm or cathode rays) is ascribed to two different types of Pr3+ sites: one with a relatively strong crystal field and the other with a relatively weak crystal field. The presence of the latter is connected with the conversion of one short-wave UV (? 215 nm) photon into two visible photons. Two-photon luminescence of Pr3+ was also found for α-NaYF4 and LaF3, but not for CaF2 and BaF2 due to the too strong crystal field in these lattices. The occurrence of two-photon Pr3+ luminescence is compared with the intensity of the IR-excited green emission of the corresponding Yb3+, Er3+-activated lattices. The intensity of the Pr3+ luminescence at shortwave UV excitation (213.9 nm) is rather weak. Luminescence of reasonable efficiency is, however, observed on excitation with cathode rays. 相似文献
9.
10.
T. Shalapska G. Stryganyuka D. Trotsc T. Demkiv A. Gektin A. Voloshinovskii P. Dorenbos 《Journal of luminescence》2010,130(10):1941-1945
LiPr1−xCexP4O12 (x=0, 0.002, 0.02; 0.1) powder samples were prepared using the melt solution technique. Luminescent parameters of LiPr1−xCexP4O12 phosphors have been investigated under ultraviolet-vacuum ultraviolet (3-12 eV) synchrotron radiation and X-rays excitation at room and near liquid He temperatures. Excitation luminescence spectra of Ce3+ emission, luminescent spectra and decay curves from the lower excited state levels of the 4f15d1 and 5d1 electronic configuration of the Pr3+ and Ce3+, respectively, clearly indicate energy transfer from Pr3+ to Ce3+. Energy migration proceeds via the Pr-sublattice followed by nonradiation transfer from Pr3+ to Ce3+ ions. 相似文献
11.
K.V. Ivanovskikh A. Meijerink A. Speghini C. Ronda M. Bettinelli 《Journal of luminescence》2010,130(5):893-16384
The silicates Ca3Sc2Si3O12, Ca3Y2Si3O12 and Ca3Lu2Si3O12, both undoped and doped with Pr3+ ions, have been synthesized by solid-state reaction at high temperature. The luminescence spectroscopy and the excited state dynamics of the materials have been studied upon VUV and X-ray excitation using synchrotron radiation. All doped samples have shown efficient 5d-4f emission upon direct VUV excitation of 5d levels, but only Ca3Sc2Si3O12:Pr3+ shows luminescence upon interband VUV or X-ray excitation. The VUV excited emission spectra of Ca3Y2Si3O12:Pr3+ and Ca3Lu2Si3O12:Pr3+ show features attributed to emission from two distinct sites accommodating the Pr3+ dopant. The decay kinetics of the Pr3+ 5d-4f emission in Ca3Sc2Si3O12:Pr3+ upon VUV excitation across the band gap are characterized by decay times in the range 25-28 ns with no significant rise after the excitation pulse. They appear to be faster upon X-ray irradiation than for VUV excitation. Weak afterglow components are attributed to defect luminescence. 相似文献
12.
《Journal of luminescence》1986,36(3):161-172
Use of site selection spectroscopic techniques combined with low temperature absorption spectral studies has enabled the identification and characterization of ten optically important charge-compensated crystallographic sites for Pr3+ in the β-ThCl4:Pr3+ system. Fluorescence decay time measurements, variation of site distribution with dopant concentration and fluorescence spectra were used to characterize the sites. Distant charge compensation is found to be one of the dominant modes of charge compensation of Pr3+ in ThCl4, and its predominance over other sites increases as Pr3+ concentration decreases. The sinusoidal distortion of the crystal field symmetry around Pr3+ in the incommensurate phase of β-ThCl4 is believed to be mainly responsible for the splitting and continuous shift in fluorescence spectral lines which occur when 3P0→3F2 fluorescence scans are made with excitation at different points on the 3P0←3H4 absorption line belonging to different sites. 相似文献
13.
14.
V.P. Bhola 《Journal of luminescence》1975,10(3):185-192
Thermoluminescence, luminescence and luminescence excitation spectra of CaF2 : Pr+3 (0.1%) at the temperature of liquid nitrogen have been investigated. Vibronic lines and lines due to cubic and tetragonal symmetries have been identified. A qualitative interpretation of the existence of both type of symmetries is also discussed. 相似文献
15.
Study of energy transfer from optically excited Eu3+ to Pr3+ has been carried out in calibo glass. Probabilities (Pda) and efficiencies (ηT) of energy transfer from Eu3+ to Pr3+ have been calculated from the life time and emission intensity of Eu3+ + Pr3+. At low acceptor concentrations, Pda varies linearly with Ca showing migration of energy among donors. At high acceptor concentrations, Pda depends linearly on (Ca + Cd)2, which is consistent with Fong and Diestler theory of dipole-dipole mechanism of energy transfer. At low temperatures the probability and the efficiency decrease due to increase in the emission intensity and life time, which suggests that at room temperature the energy is transferred to lattice by donor lowering life time and intensity. At high temperatures no emission from higher levels of donor is obtained which suggests blurring out of energy levels in glassy matrix. 相似文献
16.
Luminescent properties of Pr3+ or Mn2+ singly doped and Pr3+, Mn2+ co-doped LaMgB5O10 are investigated by synchrotron radiation VUV light. When LaMgB5O10:Pr3+ is excited at185 nm, the photon cascade emission between 4f levels of Pr3+ is observed. In the excitation spectra of LaMgB5O10:Mn2+ monitoring the 615 nm emission of Mn2+, several excitation bands in a spectral range from 330 to 580 nm are recorded, among which the most intense band is centered at 412 nm (6A1g→4Eg-4A1g). This band has considerable spectra overlap with the 410 nm emission (1S0→1I6) of Pr3+, which is favorable for energy transfer from Pr3+ to Mn2+. Such energy transfer is observed in the co-doped sample, converting the violet emission (410 nm) of Pr3+ into the red emission (615 nm) of Mn2+. The concentration dependence of transfer efficiency is also investigated. 相似文献
17.
Weiyi Jia Wuliang XuIris Rivera Angélica PérezFélix Fernández 《Solid State Communications》2003,126(3):153-157
The mixed-compound of Sr1−xCaxTiO3 has shown several compositional phase transformations. Photoluminescence and excitation spectra of the samples with different x and doped with 0.2% Pr3+ were investigated. Changes in the emission spectra were observed in different phases. The blue emission at 491 nm from 3P0 state was found quite strong in the tetragonal phase, and was thermally quenched in the orthorhombic phases. The intensity of the red luminescence from 1D2 increases with increasing content of calcium. The strongest red emission is obtained from CaTiO3:Pr3+. The results are discussed based on the configuration coordinate model and interaction of Pr with the charge transfer exciton state of the Ti complex. 相似文献
18.
《Journal of luminescence》1987,37(3):123-131
We have investigated the luminescence and absorption spectra of doped and undoped ZrO2-Y2O3 and MgO crystals at room- and low temperatures. The crystals used are partly doped with the transition metals Ni, Co, Cr and the rare earth Pr. The emission spectra were obtained under laser excitation at different wavelengths. The observed optical emission and absorption bands of the MgO crystals doped with Ni, Co and Cr correspond to transitions between spin-orbit split crystal field levels of the transition metals. Luminescence and absorption bands of undoped yttria-stabilized zirconia (YSZ) crystals are due to color centers, absorption bands of the doped YSZ correspond to the well known transitions of the Ni2+, Co2+ and Pr3+ ions, respectively. The emission spectra of the doped YSZ obtained under various laser excitations can be explained by an energy transfer process between the color center and the doping materials. The influence of annealing on the absorption and emission of Pr3+/Pr4+ is investigated. 相似文献
19.
Yizhe An 《Journal of luminescence》2005,111(3):131-138
The time dependence of thermalization between the 3P0 and 3P1 electronic states of Pr3+ in symmetrical Pr3+-Gd3+ pairs in CsCdBr3, following pulsed laser excitation into either state, is reflected in the time dependence of the luminescence from both states. The 3P0 and 3P1 states achieve thermal equilibrium in the microsecond time domain over the temperature range of study (215-340 K). Because the 3P0-3P1 energy gap is larger than the phonon cutoff in CsCdBr3, thermalization occurs via multiphonon processes. A rate-equation model for the thermalization process is presented, and the temperature dependence of the rate constants for 3P1←3P0 multiphonon absorption and 3P1→3P0 multiphonon emission is reported from 215-340 K. In contrast to CsCdBr3, the analogous thermalization kinetics in Pr3+-Gd3+ pairs in isostructural CsMgCl3 is not discernable in the 3P0 and 3P1 luminescence, because thermalization is instantaneous within the time resolution of our experiments (∼20 ns). The difference in the thermalization kinetics in the two lattices is attributed to the difference in the number of phonons required to bridge the 3P0-3P1 energy gap. 相似文献
20.
M. Fibrich H. Jelínková J. ?ulc K. Nejezchleb V. ?koda 《Applied physics. B, Lasers and optics》2009,97(2):363-367
In the present work we report on spectroscopic properties and laser results of GaN laser diode pumped Pr:YAlO3 crystal at room temperature. The polarization-resolved absorption and emission spectra have been recorded and the decay time of the 3 P 0 manifold has been measured. Three samples with different Pr3+-ion concentrations in YAP matrix have been tested and compared. The best results were achieved for 0.6 at. % Pr3+-ion doping: an output power of 91 mW at 746.9-nm wavelength with a maximum slope efficiency of 45% with respect to the absorbed power. 相似文献