共查询到20条相似文献,搜索用时 15 毫秒
1.
Tm3+:Er3+:Yb3+ doped Y2SiO5 powders were prepared by combustion synthesis with estimated as-prepared weight (wt.) % concentrations of 0.25:0.0:2.0, 0.25:0.5:2.0 and 0.25:1.0:2.0, respectively. Blue (Tm3+: 1G4 → 3H6), green (Er3+: 4S3/2, 2H11/2 → 4I15/2) and red (Er3+: 4F9/2 → 4I15/2) upconversion (UC) emissions were observed under 975 nm infrared diode laser excitation. The UC process took place via energy transfer from Yb3+ to Er3+ and Tm3+ ions. The CIE chromaticity coordinates of Tm3+:Er3+:Yb3+ doped Y2SiO5 powders were investigated as a function of the diode laser power and Er3+ concentration. 相似文献
2.
Different crystal structure of TeO2 nanoparticles were used as the host materials to prepare the Er3+/Yb3+ ions co-doped upconversion luminescent materials. The TeO2 nanoparticles mainly kept the original morphology and phase after having been co-doped the Er3+/Yb3+ ions. All the as-prepared TeO2:Er3+/Yb3+ nanoparticles showed the green emissions (525 nm, 545 nm) and red emission (667 nm) under 980 nm excitation. The green emissions at 525 nm, 545 nm and red emission at 667 nm were attributed to the 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of the Er3+ ions, respectively. For the α-TeO2:Er3+/Yb3+ (3/10 mol%) nanoparticles, three-photon process involved in the green (2H11/2 → 4I15/2) emission, while two-photon process involved in the green (4S3/2→4I15/2) and red (4F9/2 → 4I15/2) emissions. For the β-TeO2:Er3+/Yb3+ (3/10 mol%) nanoparticles, two-photon process involved in the green (2H11/2 → 4I15/2), green (4S3/2 → 4I15/2) and red (4F9/2 → 4I15/2) emissions. It suggested that the crystal structure of TeO2 nanoparticles had an effect on transition processes of the Er3+/Yb3+ ions. The emission intensities of the α-TeO2:Er3+/Yb3+ (3/10 mol%) nanoparticles and β-TeO2:Er3+/Yb3+ (3/10 mol%) nanoparticles were much stronger than those of the (α + β)-TeO2:Er3+/Yb3+ (3/10 mol%) nanoparticles. 相似文献
3.
Bright white upconversion luminescence from Er3+-Tm3+-Yb3+ doped CaSnO3 powders is obtained under the diode laser excitation of 980 nm. It is composed of three primary colors of red, green and blue emissions, which originate from the transitions of 4F9/2 → 4I15/2, (2H11/2, 4S3/2) → 4I15/2 of Er3+ ions and 1G4 → 3H6 of Tm3+ ions, respectively. The efficient upconversion emission is attributed to the energy transfer between Yb3+ and Er3+ or Tm3+ions. Moreover, it is observed that Tm3+ acts as the quenching center for the green upconversion luminescence from Er3+ ions, and the sensitizer for the red and blue luminescence when the Tm3+ doping content is less than 0.3 mol%. This is interpreted in terms of the efficient energy transfer between Tm3+ and Er3+ ions. The calculated color coordinates fall within the white region in the standard 1931 CIE chromaticity diagram, indicating the potential applications of Er3+-Tm3+-Yb3+ doped CaSnO3 in the field of displaying and lasers, etc. 相似文献
4.
D. Kasprowicz M.G. BrikA. Majchrowski E. MichalskiP. G?uchowski 《Optical Materials》2011,33(11):1595-1601
Triply-doped single crystals KGd(WO4)2:Er3+/Yb3+/Tm3+, KGd(WO4)2:Tb3+/Yb3+/Tm3+ and KGd(WO4)2:Pr3+/Yb3+/Tm3+ were grown by the Top Seeded Solution Growth (TSSG) method, with an aim of getting efficient up-converted multicolored luminescence, which subsequently can be used for generation of white light. Such an aim determined the choice of the triply doped compounds: excitation of the Yb3+ ions in the infrared spectral region is followed by red, green and blue emission from other dopants. It was shown that all these systems exhibit multicolor up-conversion fluorescence under 980 nm laser irradiation. Detailed spectroscopic studies of their absorption and luminescence spectra were performed. From the analysis of the dependence of the intensity of fluorescence on the excitation power the conclusion was made about significant role played by the host’s conduction band and other possible defects of the KGd(WO4)2 crystal lattice in the up-conversion processes. 相似文献
5.
KY3F10:Yb3+/Tm3+/Er3+ upconversion nanocrystals are synthesized via a simple hydrothermal procedure. The nanocrystals emit the near equal energy white light with high brightness and favorable color balance when excited using a 980 nm continuous wave diode laser. The research of upconversion mechanism indicates that in addition to the energy transfer processes from Yb3+ to Tm3+ and Er3+, respectively, there exists a new process 1G4 (Tm3+) + 4I11/2 (Er3+) → 3H4 (Tm3+) + 4S3/2 (Er3+). 相似文献
6.
《Advanced Powder Technology》2020,31(3):1051-1059
Novel up-conversion luminescent SrGd2(WO4)2(MoO4)2: Yb3+/Tm3+/Ho3+ nano-crystals were synthesized by hydrothermal method. The composition ratio of rare earth had been investigated. It indicated that when CYb3+ = 10 mol% and CYb3+/CTm3+/CHo3+ = 10:1.5:2, the emission intensities were the highest. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and up-conversion luminescence spectra were used to characterize SrGd2(WO4)2(MoO4)2: Yb3+/Tm3+/Ho3+ nano-crystals and they showed that the sample had high degree of crystallinity, the sample was tetragonal system, and the grain size of the sample was about 56 nm. Three emission peaks, including blue emission peak, green emission peak and red emission peak were observed at 477, 543 and 651 nm corresponding to 1G4 → 3H6 and 1G4 → 3F4 transitions of Tm3+, 5F4 → 5I8 and 5F5 → 5I8 transitions of Ho3+ respectively. All the emission peaks were observed by excitation of 980 nm semiconductor laser. The relationship between up-conversion intensity and excitation power revealed that blue emission at 477 nm was a three-photon absorption process, green emission at 543 nm and red emission at 651 nm was a two-photon absorption process. The quantum yields of the sample were near 3.2%. 相似文献
7.
Haike Ren Fugui Yang 《Journal of Materials Science: Materials in Electronics》2018,29(18):15396-15403
The Mn2+, Yb3+, Er3+: ZnWO4 green phosphors are synthesized successfully through the high temperature solid state reaction method. The micro-structure and morphology have been investigated by means of XRD and EDS. The doped concentrations of Mn2+, Yb3+, Er3+ are measured by ICP. The absorption spectra and emission spectra with different doped concentrations of Mn2+ are presented to reveal the influence of Mn2+ on the green up-conversion performance. Excited with 970 nm LED, the up-conversion emission peak at 547 nm is obtained and the CIE spectra as well as the green light photo are also presented. The results indicate that the Mn2+ ions play the role of the luminescence adjustment in the up-conversion process, which can improve the up-conversion green emission intensity effectively. The luminescence adjustment mechanism of Mn2+ ions in Mn2+, Yb3+, Er3+: ZnWO4 green phosphors has been discussed. The crystal parameters of Dq, B and C are calculated to evaluate the energy level split effect. 相似文献
8.
《Materials Letters》2007,61(11-12):2200-2203
Er3+/Tm3+/Yb3+ tridoped oxyfluoride glass ceramics was synthesized in a general way. Under 980 nm LD pumping, intense red, green and blue upconversion was obtained. And with those primary colors, multicolor luminescence was observed in oxyfluoride glass ceramics with various dopant concentrations. The red and green upconversion is consistent with 4F9/2 → 4I15/2 and 2H11/2, 4S3/2 → 4I15/2 transition of Er3+ respectively. While the blue upconversion originates from 1G4 → 3H6 transition of Tm3+. This is similar to that in Er3+/Yb3+ and/or Tm3+/Yb3+ codoped glass ceramics. However the upconversion of Tm3+ is enhanced by the energy transfer between Er3+ and Tm3+. 相似文献
9.
Mingzhu Li Fang Lu Fei Xu Zuimin Jiang Xiao Wang Haonan Lou Zhongquan Ma Lingling Zheng 《Materials Chemistry and Physics》2012
Near-infrared photoluminescence (PL) of calcium boroaluminate (CABAL) glasses codoped with Er2O3 and Tm2O3 has been investigated by dual-wavelength pumping at 795 and 476 nm. Spectrum shape of broadband emission could be modulated by controlling the power ratio of two pumping lines (P476/P795). The result shows that the full width at half maximum can reach ∼500 nm in the wavelength range from 1.3 to 2.0 μm by controlling P476/P795 = 12. The PL spectra show four characteristic peaks located at 1.46, 1.53, 1.58 and 1.80 μm, corresponding to Tm3+: 3H4 → 3F4, Er3+: 4I13/2 → 4I15/2, Tm3+: 1G4 → 3F2 and Tm3+: 3F4 → 3H6 emissions, respectively. The energy transfer (ET) (ET1: Er3+: 4I13/2, Tm3+: 3F4 → Er3+: 4I15/2, Tm3+: 3H4 and ET2: Er3+: 4I13/2, Tm3+: 3H6 → Er3+: 4I15/2, Tm3+: 3F4) between Er3+ and Tm3+ ions play important roles in the luminescence mechanisms. In addition, a new ET process (ET: Tm3+: 1G4, Er3+: 4F9/2 → Tm3+: 3F2, Er3+: 4F7/2) was identified. The flat broadband emission with the bandwidth of ∼500 nm could be realized by changing P476/P795 as a result of the radiative transitions, Tm–Tm cross-relaxation (Tm3+: 3H4, 3H6 → Tm3+: 3F4, 3F4) and Er–Tm ET processes. 相似文献
10.
Yb3+/Er3+ codoped BaGd2(MoO4)4 phosphor powders were prepared by the Sol-gel method and the upconversion luminescence properties were investigated in detail. Under 980 nm semiconductor laser excitation, BaGd2(MoO4)4:Yb3+,Er3+ phosphor exhibits green upconversion luminescence with peaks at 530 and 550 nm, which are due to the transitions of Er3+ (2H11/2) → Er3+ (4I15/2) and Er3+ (4S3/2) → Er3+ (4I15/2), respectively. Both of the two green emission lines are produced by populating Er3+ ions to the excited state through a two-photon process. By monitoring the intensities of the green upconversion luminescence, the optimum conditions for the Sol-gel synthesis were determined when the molar ratio of citric acid to total chelate metal cations was 2:1 and the sintering temperature was at 1073 K. The concentration quenching effect for Er3+ was found at the optimum doping concentration of 6 mol%, and the critical distance for the neighboring Er3+ was determined to be about 21.5 Å. 相似文献
11.
Transparent glass ceramics have been obtained by nucleation and growth of Y2Te6O15 or Er2Te5O13 cubic phase in a new Er3+-doped oxyfluoride tellurite glass. Effect of heat treatment on absorption spectra, luminescence and up-conversion properties in the oxyfluoride tellurite glass has been investigated. With heat treatment the ultraviolet absorption edge red shifted evidently for the oxyfluoride telluride glass. The near infrared emission that corresponds to Er3+:4I13/2 → 4I15/2 can be significantly enhanced after heat treatment. Under 980 nm LD pumping, red and green up-conversion intensity of Er3+ in the glass ceramic can be observed much stronger than that in the base glass. 相似文献
12.
《Journal of Experimental Nanoscience》2013,8(12):947-964
LaOCl:Yb3+, Er3+ nanobelts were prepared by electrospinning combined with a double-crucible chlorination technique using NH4Cl as chlorinating agent. X-ray powder diffraction analysis indicated that LaOCl:Yb3+, Er3+ nanobelts were tetragonal with space group P4/nmm. Scanning electron microscope analysis and histograms revealed that width of LaOCl:Yb3+, Er3+ nanobelts was 6.12 ± 0.18 μm under the 95% confidence level, and the thickness was 113 nm. Transmission electron microscope observation showed that as-obtained LaOCl:Yb3+, Er3+ nanobelts were composed of nanoparticles. LaOCl:Yb3+, Er3+ nanobelts emitted strong green and red up-conversion emission centring at 523, 551 and 667 nm, respectively, attributed to 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4Il5/2 transitions of Er3+ under the excitation of a 980-nm diode laser (DL) excitation. Moreover, the near-infrared characteristic emission of LaOCl:Yb3+, Er3+ nanobelts was achieved under the excitation of a 532-nm laser. Commission Internationale de L'Eclairage analysis demonstrated that colour-tuned luminescence can be obtained by changing doping concentration of Yb3+ and Er3+, which could be applied in the fields of optical telecommunication and optoelectronic devices. The up-conversion luminescent mechanism and the formation mechanism of LaOCl:Yb3+, Er3+ nanobelts were also proposed. 相似文献
13.
《Materials Letters》2005,59(24-25):3066-3068
Blue, green and red emissions through frequency upconversion and energy transfer processes in Tm3+/Er3+/Yb3+-codoped oxyhalide tellurite glass under 980 nm excitation are investigated. The intense blue (476 nm), green (530 and 545 nm) and red (656 nm) emissions are simultaneously observed at room temperature. The blue (476 nm) emission was originated from the 1G4→3H6 transition of Tm3+. The green (530 and 545 nm), and red (656 nm) upconversion luminescences were identified from the 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2 transitions of Er3+, respectively. The energy transfer processes and possible upconversion mechanisms are evaluated. 相似文献
14.
Congbing Tan Yunxin Liu Wenbin LiYutao Zhang Yunan Han 《Materials Science and Engineering: B》2011,176(16):1251-1256
Lanthanide-doped uniform pure cubic phase Y2O3 hollow microspheres have been successfully synthesized via a facile, high yield urea-based coprecipitation route with assistant of carbon spheres templates. The diameter and shell thickness of the microspheres can be manipulated by adjusting carbon sphere templates. Under a 980 nm excitation, Yb3+/Er3+, Er3+, Yb3+/Tm3+-doped Y2O3 hollow microspheres emit bright upconversion red, green, blue light with high purity, respectively, while Eu3+, Eu3+/Tb3+-doped Y2O3 hollow microspheres exhibit intense downconversion red light under the excitation of 254 nm ultraviolet light. Especially, the 610 nm emission intensity of Eu3+ in the Eu3+/Tb3+-codoped Y2O3 hollow microspheres is almost 5 times of that in the Y2O3:Eu3+ hollow microspheres indicating the occurring of the energy transfer from Tb3+ to Eu3+ ions. 相似文献
15.
Jinsheng Liao Liling Nie Shaohua Liu Bao Liu He-rui Wen 《Journal of Materials Science》2014,49(17):6081-6086
Pyrochlore Y2Sn2O7 nanophosphors codoped with Er3+ (fixed 2 at.%) and Yb3+ ions (2–16 at.%) were synthesized via hydrothermal process followed by heat treatment. We investigate the infrared-to-visible upconversion (UC) luminescence properties of Er–Yb codoped Y2Sn2O7. Upon 980 nm excitation at room temperature, green (at ~522 and 544 nm) and red (at ~661 nm) UC emissions were observed, which are ascribed to the (2H11/2, 4S3/2) → 4I15/2 and 4F9/2 → 4I15/2 transitions, respectively. It has been found that the Yb3+-doping concentrations have greatly influenced on the UC luminescence intensity and the emission ratio of the red and green in Y2Sn2O7:Yb3+/Er3+ nanophosphors. The tunable emission is due to the energy back transfer from Er3+ to Yb3+ and the cross relaxation between the two neighboring Er3+ ions. It is expected that the achieved single and intense red emission band may have potential application for in vivo bioimaging. 相似文献
16.
Synthesis and upconversion luminescence properties of the new BaGd2(MoO4)4:Yb3+,Er3+ phosphor were reported in this paper. The phosphor powder was obtained by the traditional high temperature solid-state method, and its phase structure was characterized by the XRD pattern. Based on the upconversion luminescence properties studies, it is found that, under 980 nm semiconductor laser excitation, BaGd2(MoO4)4:Yb3+,Er3+ phosphor exhibits intense green upconversion luminescence, which is ascribed to 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transition of Er3+. While the observed much weaker red emission is due to the non-radiative relaxation process of 4S3/2 → 4F9/2 and 4F9/2 → 4I15/2 transition originating from the same Er3+. The concentration quenching effects for both Yb3+ and Er3+ were found, and the optimum doping concentrations of 0.5 mol% Yb3+ and 0.08 mol% Er3+ in the new BaGd2(MoO4)4 Gd3+ host were established. 相似文献
17.
Tanggang Li Suwen Liu Haiping Zhang Enhua Wang Lingjun Song Ping Wang 《Journal of Materials Science》2011,46(9):2882-2886
Infrared-to-ultraviolet upconversion luminescence agent Y2O3:Yb3+,Tm3+ was prepared by a combustion method using citrate as a fuel/reductant. The prepared sample was characterized by X-ray diffraction,
SEM, and fluorescence spectrophotometer. Two unusual 1I6 → 3H6 (~297 nm) and 1D2 → 3H6 (~363 nm) emissions from Tm3+ ions were observed at room temperature under 980-nm laser excitation. The change of upconversion emission intensity depending
on the Yb3+ concentrations was discussed. The results showed that modest Yb3+ doping could make the upconversion emission of Tm3+ intense, and high Yb3+ concentrations might lead to fluorescence quenching. Moreover, the influence of ultraviolet upconversion luminescence on
the photodegradation of methyl orange aqueous solution under solar light irradiation in the presence of TiO2 catalyst doped with Y2O3:Yb3+,Tm3+ was also investigated. It was concluded from the experiment of this study that TiO2/Y2O3:Yb3+,Tm3+ composite had higher photocatalytic activity than pure TiO2 under solar light. This study would make TiO2 utilize sunlight more efficiently and accelerate the practical application of photocatalytic technology in water treatment
region. 相似文献
18.
2 mol% Tm3+ doped NaYF4 phosphors with 0–98 mol% Yb3+ codoping were synthesized by sol–gel method. The phase transition from the mixture of hexagonal and cubic phases to single cubic phase of Tm3+–Yb3+:NaYF4 phosphors was investigated with increasing of Yb3+ concentration. Near-infrared, red, blue, violet and ultraviolet upconversion emissions of Tm3+ were observed from the Tm3+–Yb3+:NaYF4 phosphors under 976 nm laser diode excitation, with the strongest near-infrared to ultraviolet emissions at 20 mol% Yb3+ codoping. The violet and blue emissions for the 1D2 → 3F4 and 1G4 → 3H6 transitions of Tm3+ can be tuned by varying Yb3+ codoping concentration, which was elucidated using steady-state equations. The intensity ratio of red emissions for the 3F2 → 3H6 and 3F3→3H6 transitions of Tm3+ was strongly related to the Yb3+ codoping concentration and temperature, implying a potential application of Tm3+–Yb3+:NaYF4 phosphors for optical temperature sensing. 相似文献
19.
Xiaochen Yu Feng Song Changguang Zou Lanjun Luo Chengguo Ming Wentao Wang Zhenzhou Cheng Lin Han Tongqing Sun Jianguo Tian 《Optical Materials》2009,31(11):1645-1649
The effect of temperature on the luminescence intensity of up-conversion and near infrared in Er3+/Yb3+ co-doped phosphate glass ceramics has been investigated. Efficient green and red up-conversion luminescence and strong infrared fluorescence at 1.54 μm wavelength are observed under excitation of 975 nm. The fluorescence intensity is changing at different temperature and the results are explained with the level transitions in Er3+/Yb3+ co-doped system. Meanwhile, the lifetime of Er3+:4I13/2 level corresponding to different operating temperature and pump power is also discussed, and the experimental results are fitted using multiphonon relaxation theory. 相似文献
20.
The vacuum ultraviolet excited luminescent properties of Eu3+, Tb3+, Dy3+, Sm3+ and Tm3+ in the matrices of Ca4Y6(SiO4)6O were investigated. The bands at about 173 nm in the vacuum ultraviolet excited spectra were attributed to host lattice absorption of the matrix Ca4Y6(SiO4)6O. For Eu3+-doped samples, the O2− → Eu3+ CTB was identified at 258 nm. Typical 4f-5d absorption bands in the region of 195-300 nm were observed in Tb3+-doped samples. For Dy3+-doped and Sm3+-doped samples, the broad excitation bands consisted of host absorptions, CTB and f-d transition. For Tm3+-doped samples, the O2− → Tm3+ CTB was located at 191 nm. About the color purity and emission intensity, Ca4Y6(SiO4)6O:Tb3+ is an attractive candidate of green light PDP phosphor, and Ca4Y6(SiO4)6O:Dy3+ has potential application in the field of mercury-free lamps. 相似文献