Дисертації з теми "Rare earth phosphors"
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Shalav, Avi School of Photovoltaic & Renewable Energy Engineering UNSW. "Rare-earth doped up-converting phosphors for an enhanced silicon solar cell response." Awarded by:University of New South Wales. School of Photovoltaic and Renewable Energy Engineering, 2006. http://handle.unsw.edu.au/1959.4/24184.
Повний текст джерелаGao, Yuan. "Design of rare-earth-doped inorganic phosphors and luminescence enhancement by plasmonic effects." Kyoto University, 2020. http://hdl.handle.net/2433/253288.
Повний текст джерелаNishiura, Shotaro. "Preparation and Optical Properties of Rare Earth Doped Ceramic Phosphors for White Light Emitting Diode." Kyoto University, 2013. http://hdl.handle.net/2433/175019.
Повний текст джерела0048
新制・課程博士
博士(人間・環境学)
甲第17670号
人博第637号
新制||人||153(附属図書館)
24||人博||637(吉田南総合図書館)
30436
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授 田部 勢津久, 教授 杉山 雅人, 教授 加藤 立久
学位規則第4条第1項該当
Katayama, Yumiko. "Optical and photo-electric studies on quantum cutting and persistent luminescent phosphors doped with rare-earth and transition-metal ions." Kyoto University, 2014. http://hdl.handle.net/2433/188818.
Повний текст джерела0048
新制・課程博士
博士(人間・環境学)
甲第18380号
人博第693号
新制||人||166(附属図書館)
25||人博||693(吉田南総合図書館)
31238
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授 田部 勢津久, 教授 加藤 立久, 教授 杉山 雅人, 教授 森本 芳則, 教授 山本 行男
学位規則第4条第1項該当
Legentil, Paul. "Développement de poudres hybrides "Hydroxydes Doubles Lamellaires-luminosphores" sans terres rares. Intégration dans des revêtements composites compatibles avec des sources d'excitation LED." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAC013.
Повний текст джерелаThese works have the ambition to offer alternative solutions to phosphors with rare-earth elements, displaying suitable performance for LED devices applications as well as signage or display applications. We have been interested in organic as well as inorganic phosphors such as quantum dots (QD). The main problem encountered with these compounds is their relative instability under thermal and/or photonic stresses. Thus, in order to overcome this issue, we decided to use inorganic materials called layered double hydroxide (LDH) as host matrix to protect these phosphors. Several experimental techniques (XRD, SAXS, IR, SEM, TEM…) have been used to characterize structural and morphological properties. Optical properties have also been recorded (emission and excitation spectra, photoluminescence quantum yields, fluorescence decay…). Using extremely small amounts of phosphors, it is demonstrated here that Zn2Al cation-based LDH tethering acts as a «solid solvent» for the dye, enabling its luminescence even in powder form. Additionally, LDH platelets are found to help the dispersion of the dye or QD in silicone to obtain homogeneous composite films, which exhibit luminescent properties. Finally, the stability of composite coatings (LDH-phosphor/silicone) under different stresses (thermal and photonic) is most often improved
Ireland, Terry G. "Precipitation techniques and characterisation of rare earth element doped phosphor materials." Thesis, University of Greenwich, 2008. http://gala.gre.ac.uk/6195/.
Повний текст джерелаNgwenya, Bryne Tendelo. "Magmatic and post-magmatic geochemistry of phosphorus and rare earth elements in carbonatites." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306803.
Повний текст джерелаBoonsin, Rachod. "Développement de luminophores sans terres rares pour l'éclairage éco-énergétique à base de diodes électroluminescentes." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22704/document.
Повний текст джерелаLighting technologies based on light-emitting diodes have become an alternative solution over the obsolete technologies (fluorescent lamps and incandescent lamps) due to their positive key criteria of environmental conservation: reduction of energy consumption and mercury/lead-free with 98% recycling technologies. However, the rare-earth elements, which are currently used in LED lightings, are produced by China at about 95%, thereby creating a monopoly situation on the rare-earth elements’ market and also a risk to the deployment of LED technologies in coming years. In this work, we have been interested in the development of rare-earth-free luminescent materials for LED lighting applications in order to produce a white light emission. Three kinds of rare-earth-free luminescent materials have been investigated: organic phosphors, hybrid (organic-inorganic) phosphors and core-shell quantum dots (QDs). The optical studies of these phosphors recorded upon UV and/or blue excitations allow us to determine their colorimetric parameters (CRI, T(K), PLQY(%)) and to demonstrate their optical performances for use in lighting devices. In order to yield a color emission close to ideal white light, the best phosphors were selected and then introduced by mixing them in appropriate proportions into silicone polymers. Another part of this work was devoted to the studies of stability of phosphors (films or powders) under operating conditions of LEDs, moreover, variation of their optical properties as a function of time and temperature were also determined. The optical performances about 30% have been recorded with some interesting colorimetric parameters. Although these materials have presented lower photoluminescence properties compared with commercial rare-earth based inorganic phosphors for “public lighting” applications, they can already be positioned on other luminescent sectors such as indoor lighting, signage anti-counterfeit marking
Yamane, H., T. Kawano, K. Tatsumi, S. Muto, and Y. Fujimichi. "Quantitative determination of site occupancy of multi-rare-earth elements doped into Ca2SnO4 phosphor by electron channeling microanalysis." Elsevier, 2010. http://hdl.handle.net/2237/20789.
Повний текст джерелаZhang, Lilu. "Synthesis and chemistry of lanthanide complexes with phosphorus ylides, amides or porphyrinate ligands, and of transition metal complexes with polydentate ligands." HKBU Institutional Repository, 1999. http://repository.hkbu.edu.hk/etd_ra/182.
Повний текст джерелаYamane, H., T. Kawano, K. Tatsumi, Y. Fujimichi, and S. Muto. "Site occupancy determination of Eu/Y doped in Ca2SnO4 phosphor by electron channeling microanalysis." Elsevier, 2011. http://hdl.handle.net/2237/20827.
Повний текст джерелаПляцук, Леонід Дмитрович, Леонид Дмитриевич Пляцук, Leonid Dmytrovych Pliatsuk, Єлізавета Юріївна Черниш, Елизавета Юрьевна Черныш, Yelyzaveta Yuriivna Chernysh та М. О. Алієва. "Огляд проблематики комплексної переробки фосфогіпсу". Thesis, Сумський державний університет, 2017. http://essuir.sumdu.edu.ua/handle/123456789/66521.
Повний текст джерела張馨友. "Synthesis and Luminescence Characterization of Rare-Earth Activated Alkaline-Earth Thiogallate and Oxythiogallate Phosphors." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/87269149789658585830.
Повний текст джерела國立交通大學
應用化學系碩博士班
99
In an attempt to investigate phosphors for light emitting diode (LED) application, we have successfully synthesized four series of thiogallate and oxythiogallate phosphors with compositions of SrLaGa3S6O:Ln (Ln = Ce3+, Eu2+, Ce3+/Li+ or Ce3+/Eu2+), (Sr1-xAx)LaGa3S6O:Ce3+ (A = Ca, Ba), Ca(La1-yMy)Ga3S6O:Ce3+ (or Eu2+) with M = Y, Gd,, and Sr2Ga2S5:Ce3+, respectively, by solid-state method under reduction atmosphere of H2S/Ar. .The crystal structure, luminescence, chromaticity and thermal luminescence quenching properties have been characterized by using X-ray diffraction (XRD), diffuse reflectance, and fluorescence spectroscopy. We first investigated the optimization of synthetic conditions of all phosphors and carried out phase identification using XRD. We then investigated luminescence spectra of thiogallate and oxythiogallate and found that both can be excited in the range of 300-450 nm with optimal excitation at 397 nm (Ce3+-activated phases) and 405 nm (Eu2+-activated phases), respectively. The effect of crystal field strength on the luminescence of the (Sr1-xAx)LaGa3S6O:Ce3+ (A = Ca, Ba) and Ca(La1-yMy)Ga3S6O:Ce3+ (M = Y, Gd) systems has also been studied by cation substitution for Sr2+ and La3+, respectively. The energy transfer from Ce3+ to Eu2+ in SrLaGa3S6O:Ce3+,Eu2+ was investigated and found to occur via a resonance-type dipole-dipole mechanism. The chromaticity coordinates of SrLaGa3S6O:5%Ce3+,xEu2+was observed to shift from blue to yellowish-green with x increasing from to 0.10. Furthermore, the charge compensation study revealed that the emission spectrum of charge-compensated SrLaGa3S6O:Ce3+,Li+ red-shifted as compared to that of the uncompensated (Sr1-nCen)LaGa3S6O phase. Finally, we have studied the temperature-dependent luminescence intensity for the SrLaGa3S6O:Ln (Ln = Ce3+, Eu2+) and Sr2Ga2S5:Ce3+ phosphors and discovered that the thermal quenching was observed to be more serious in Sr2Ga2S5:Ce3+ than that observed in SrLaGa3S6O:Ln.
Liu, Tzu-Chen, and 劉子晨. "Structural and Luminescent Properties of Multi-functional Rare-earth Doped Phosphors." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/21693165927719900386.
Повний текст джерела國立臺灣大學
化學研究所
100
The applications of phosphors according to different excitation sources are versatile due to the utilization of rare earth ions. The tunable energy levels of 5d orbital and the large number of energy levels of 4f orbitals can emit photons with different wavelength. In this thesis, excitation sources from vacuum ultraviolet (VUV), ultraviolet (UV) to visible photons, and electrons are investigated. Emission ranges from UV to visible range and near-infrared (NIR) are also utilized. The third chapter focuses on the synthesis of red-emitting oxynitride phosphor. Intraconfigurational 4f → 4f transitions are designed because of the determined environment for 5d → 4f transitions. The high thermal stability reveals that β–SiAlON is a good candidate for white light-emitting diodes (wLEDs) and plasma display panels (PDP). Pr3+ ions show the possibility of an alternative for red emitting activators. In the fourth chapter, comparison of LED- and FED-used phosphors under electron bombardment is made and it suggests a new class of host lattice should be developed. Evidences from solid-state nuclear magnetic resonance (ssNMR) lead to a different explanation of the incorporation of rare-earth ions into AlN host lattice. A new phosphor composition of AlN doped with Si4+ and Ce3+ ions is synthesized and shows the validity for field emission displays. The fifth chapter includes two proposed quantum cutting (QC) rare-earth combination for enhancing the efficiency of crystalline silicon (c-Si)-based solar cells: (1) adding a sensitizer to transfer the excited energy to the donor with 4f → 4f transitions , and (2) using a broad band donor such as Eu2+ and Ce3+ ions. It is concluded that due to the high energy of phonons required for Ce3+ ions, Eu2+-Yb3+ pairs is a better choice.
Sun, Jui-Ling, and 孫瑞伶. "Preparation and Luminescent Properties of Rare Earth-activated Red Emission Phosphors." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/9tneas.
Повний текст джерела國立交通大學
平面顯示技術碩士學位學程
105
In this study, we successfully prepared the novel fluorescent materials and discussed their synthesis methods, luminescence properties and luminescent mechanism to apply to white light emitting diodes. The high temperature solid state method was used to synthesize the new phosphors, Ca2Y8Si6O26:Sm3+, La5BSi2O13:Sm3+, and BaY2Si3O10:Sm3+ with different calcination temperature. The X-ray diffraction, Electron microscopy, fluorescence spectrometer, temperature analyzer, chromaticity coordinates were used to analyze the crystal structure parameters, surface morphology, luminescent properties, fabrication performance, thermal stability and so on. The rare earth ions Sm3+ belong to the f-f forbidden transition, and the experimental results showed that there were multiple absorption narrow peaks appear ranged from 300 nm to 500 nm, which covered with the ultraviolet light and blue chip package. The strongest emission peak of Ca2Y8Si6O26:Sm3+ is locating at 648 nm, the strongest emission peak of BaY2Si3O10:Sm3+ is centered at 602 nm, and the strongest emission peak of La5BSi2O13:Sm3+ is near to 602 nm, and the phosphors are shot out of orange light. In this paper, the red light phosphors were packaged with BaMgAl10O17:Eu2+ blue commercial phosphor and (Ba, Sr)2SiO4:Eu2+ respectively with current red-emitting phosphors with a 390 nm wavelength N-UV light to investigate its luminescent properties.
LI, YI-SIOU, and 李逸修. "Synthesis and Luminescent Properties of Alkaline Earth Metal Tellurite Phosphors Doped with Rare Earth Elements." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/7xre9h.
Повний текст джерела明新科技大學
化學工程與材料科技系碩士班
107
The main lattice material of this study is carbonate,Doping the activation centers: Tb3+, Gd3+, Ce3+, respectively, to prepare red, green, and blue primary color phosphors,The synthesis method is a wet method in a solid-phase synthesis method, and is heated to 900℃and 1400℃at a temperature increase rate of 10℃per minute in a high-temperature furnace, and the calcination is carried out for 10 hours while the calcination is completed. The phosphor powder is finished and tested. The crystal structure is detected by X-ray diffraction (XRD), and the excitation and emission spectra of the phosphor are detected by photoluminescence (PL). Enter the CIE chromaticity coordinate map to know the exact color of the sample. 1.Sr2SiO4 series The sample with added Ce3+ ions has nonlinear optical blue light, and the sample with Tb3+ ions emits green light, while the addition of two rare piles of the earth (Ce3+, Tb3+) emits blue light and also has the characteristics of the above two samples. 2.Ba2SiO4 series The sample with Ce3+ ion added and calcined at 1400 °C has a nonlinear optical blue light. The sample with Tb3+ ion and calcined at 1400 °C emits green light while adding two rare piles of the earth (Ce3+, Tb3+) to emit blue light. With the characteristics of the above two samples, the same calcination temperature is also visible at 1400 °C. 3.Ca2SiO4 series When the calcination temperature is 1400 °C, the luminescence efficiency and crystallinity are better. The sample with Ce3+ has nonlinear optics and emits blue light; the sample with Tb3+ emits green light; while the sample with Ce3+ and Tb3+ remains at the same time. The characteristics of the aforementioned samples showed that the sample to which Gd3+ was added emitted red light.
Wu, Eason, and 吳義森. "Luminescent properties of rare earth-activated YVO4-based phosphors and thin films." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/43996472724481857421.
Повний текст джерела國立成功大學
電機工程學系碩博士班
96
Rare earth-activated YVO4 phosphors have been attracting more attention in recent years because of their high luminescent intensities and stability under UV or UVU excitation as comparison with the conventional phosphors. Thus, rare earth-activated YVO4 phosphors have been considered as one possible luminescent material for flat display devices, such as plasma display panel (PDP) and field emission displays (FED). In this thesis, we have employed solid state reaction method and successfully prepared Tm- and Dy-codoped YVO4 with high luminance of white light emission. The relationship between the ratio of Tm3+/Dy3+ and the chromaticity is also studied. The best white-light emission was observed with YVO4:0.01mol(Tm0.2Dy0.8). Since the energy is efficiently transferred from VO43- to the two dopants Tm3+ and Dy3+, YVO4:0.01mol(Tm0.2Dy0.8) exhibits a strong white light emission. Additionally, we have investigated the morphological crystal structure and luminescent properties of YVO4:0.01mol(Tm0.2Dy0.8) thin film phosphors deposited by RF magnetron sputtering deposition. In particular, the effects of pressure, power and annealing temperature on luminescent properties of YVO4:0.01mol(Tm0.2Dy0.8) thin film phosphors have been examined. We concluded that the best white-light emission is achieved under the following conditions: pure Ar atmosphere, pressure of 5mtorr, RF power of 200W, substrate temperature of 350℃ and annealing temperature of 800℃.
Han-LinHsu and 徐漢霖. "Synthesis and luminescent properties of rare-earth ion doped Li3Ba2La3(MoO4)8 phosphors." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/42024449184955709194.
Повний текст джерела國立成功大學
材料科學及工程學系碩博士班
98
Rare-earth (RE) ion doped phosphors, Li3Ba2La3-xREx(MoO4)8 (RE = Eu3+, Dy3+), were synthesized by a solid-state reaction process at 800C. The structural and photoluminescent properties of the prepared phosphors were investigated by X-ray diffraction, scanning electron microscopy, Raman scatter spectroscopy, UV-visible absorption, and photoluminescence (PL) spectroscopy. The aim of the research was to develop novel phosphors for the UV-LED to white light conversions. The experimental results showed that the dominant emissions of the Li3Ba2La3-xEux(MoO4)8 phosphors under the UV excitation (394 nm) were at 593 nm and 618 nm, originating from the electronic transitions between the trivalent RE states. Due to the high phonon frequency of the host lattice, the transitions from the emitting levels higher than 5D0 were not observed in the PL spectra. The above two observed emissions were due to the 5D0->7F1 (593 nm) and 5D0->7F2 (618 nm) transitions. In particular, the 5D0->7F2 emission was very strong and for the x=2.1 samples, its peak intensity was about 3.3 times more than the commercial phosphors ZnS:(Mn2+,Te2+). The CIE chromaticity coordinate of the Li3Ba2La0.9Eu2.1(MoO4)8 red emissions was calculated to be at (0.67, 0.33), which is almost the same as the standard red chromaticity of the NTSC system. In the Li3Ba2La3-xDyx(MoO4)8 (x=0.01-0.24) series, the dominant emissions under the UV excitation (388 nm) were from the 4F9/2->6H15/2 (blue) and 4F9/2->6H13/2 (yellow) transitions, and the intensity of the later was stronger. The mixture of all the emissions had the CIE chromaticity coordinates at (0.35, 0.40), which is at the yellowish-white color region.
Huang, Yun-Chi, and 黃云琪. "Synthesis, Luminescence Characterization and Potential Applications of Rare Earth Fluorosulfide and Fluorooxysulfide Phosphors." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/77206348880428747842.
Повний текст джерела國立交通大學
應用化學系碩博士班
101
White LEDs fabricated with blue or near-UV LED chips and compatible R/G/B phosphors is the main stream of current solid-state lighting device. This research is attempted to develop new fluorosulfide and oxyfluorosulfide phosphors undisclosed in the literature or patent application. We have prepared four series phosphors with compositions of CeSF:Lnn+ (Lnn+ = Gd3+, Y3+, Tb3+, Mn2+), La3OF3S2:Ce3+, Ce2CaF4S2:Tb3+ and (Ce1-xYx)2SrF4S2 by solid-state reactions in evacuated sealed quartz glass tubes at 900-1000℃, which were further characterized by powder X-ray diffraction, fluorescence spectroscopy, and electron microscopy to investigate their phase identity, luminescence, microstructures, chromaticity, quantum efficiency and thermal luminescence quenching behaviors. Based on the characterization results, we then evaluated their potential applications in fabrication of white light LEDs. This thesis first investigates the optimization of synthesis conditions and performs X-Ray diffraction characterization and phase identifications. The second part deals with the luminescence of La3OF3S2:Ce3+ and the third part investigates the luminescence of Mn2+-doped fluorosulfide and oxyfluorosulfide phosphors. Fourthly, this research investigates the luminescence of Ce3+/Tb3+-codoped fluorosulfides and studies the possibility of Ce3+ → Tb3+ energy transfer. Finally, we investigated the thermal luminescence quenching property of all synthesized phosphors and fabricated a white-light LED device using Ce2CaF4S2:Tb3+ and blue-emitting commodity phosphors in combination of a 365 nm near-UV LED chip.
Lin, Han-Yu, and 林含諭. "The Syntheses and Optical Investigations of New Phosphors: Calcium Vanadates Codoped with Alkaline Earth and Rare Earth Ions." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/13211703362314433240.
Повний текст джерела國立成功大學
奈米科技暨微系統工程研究所
97
In this thesis, the (Ca, IIA)3(VO4)2: Eu3+ (IIA=Mg, Sr, Ba) red phosphors were prepared by the solid-state reaction method for the first time, and the preferable sintered condition was obtained at 1050 oC for 6 h. To improve the luminescence intensity of Ca2.82(VO4)2: 0.12Eu3+, an attempt was made to replace Ca2+ by (IIA)2+. It was found either of IIA substitution enhanced the PL intensity of Ca2.82(VO4)2: 0.12Eu3+ at different (IIA)2+ contents under 465 nm excitation. According to the changes of the lattice constants, this enhancement may originate from the lower site symmetry of the Eu3+ ion in the center with noninversion symmetry. It was noted Ba2+ was the best choice of (IIA)2+ ions (IIA=Mg, Sr, Ba) in partial substitution for Ca2+ to enhance the PL intensity. And the optimum value of the Ba2+ content (y) was at 9.9 mol% in (Ca1-yBay)2.82(VO4)2: 0.12Eu3+. The (Ca0.901Ba0.099)2.82(VO4)2: 0.12Eu3+ phosphor showed 136% improved integrated intensity than that of the Ca2.82(VO4)2: 0.12Eu3+ phosphor. Compared to commercial oxysulfide and sulfide red phosphors suitable for blue excitation, our synthesized phosphor (Ca, Ba)3(VO4)2: Eu3+ has the advantages of no chemical instability and sulfur pollution. The luminescence intensity of (Ca0.901Ba0.099)2.82(VO4)2: 0.12Eu3+ phosphor has been successfully further enhanced by adding the sensitizer, Sm3+ ion. We have discovered the energy transfer from Sm3+ to Eu3+ through the relative decline and growth in emission peaks of Sm3+ and Eu3+, respectively, as well as the variation of the decay behaviors of the Sm3+ 4G5/2→6H9/2 transition with the increasing Eu3+ content. The mechanism of the energy transfer from Sm3+ to Eu3+ was investigated and determined as the dipole-quadrupole interaction. The energy transfer efficiency, probability and the critical concentration in our Sm3+→Eu3+ system were also estimated. The optimized red phosphor (Ca0.89Ba0.099)2.82(VO4)2: 0.02Sm3+, 0.12Eu3+ is well-excited by the 465 nm blue lights, so it gives a potential for this phosphor to be applied on the phosphor-converted white LED with a blue chip (450-470 nm). Besides, the good overlap of the PLE and PL spectrum of (Ca0.89Ba0.099)2.82(VO4)2: 0.02Sm3+, 0.12Eu3+ phosphor and the absorption spectrum of CuPc indicates the potential use of the down-conversion phosphor coating to increase the performances of CuPc-based solar cells. We also synthesized the new infrared Ca3(VO4)2: Yb3+ phosphors suitable for UV excitation. The infrared emission peak at 983 nm under excitation of 310 nm was observed and the optimum Yb3+ content was 14 mol%. And the sufficiently large SR’s variation (~0.6 A/W) of a poly-Si solar cell for this phosphor indicates this phosphor can be used as a potential candidate to increase the power conversion efficiency of poly-Si solar cells.
Chen, Shing-Nian, and 陳星年. "The Synthesis and Luminescence Characterization of Some Rare Earth-Doped Fluorosulfide and Oxyfluorosulfide Phosphors." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/30524417694768071046.
Повний текст джерела國立交通大學
應用化學系分子科學碩博士班
100
Fluorosulfide and oxyfluorosulfide-based phosphors have relatively low synthetic temperature and appropriate excitation wavelengths for applications in fabricating white-light LEDs. To enhance the thermal stability of sulfides, we choose the fluorosulfides and oxyfluorosulfide as host matrices and activated with Ce3+ and Eu2+ as activator, respectively. In this study, we have prepared five series of fluorosulfide and oxyfluorosulfide phosphors, viz., Y3S2OF3:Ce3+, La2MF4S2:Ce3+ and La2MF4S2:Eu2+(M = Ca, Sr) using sealed quartz tube at 850-1000℃and 1150℃, respectively. These phosphors can be excited by radiation with wavelength ranging from 300 nm to 500 nm and their emission colors almost cover the whole visible spectral range. The content of this thesis can be divided into two parts. Firstly, we will introduce the background knowledge of phosphors used in LEDs, and then elaborate the design rules, the motivations and goals of the study. The synthetic methods and further characterization results will be discussed in the second part.
Chang, Yee-Cheng, and 張翌誠. "Synthesis and photo-luminescence properties of rare earth ion doped Li3Ba2Gd3(MoO4)8 phosphors." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/03947122628165768871.
Повний текст джерела國立成功大學
材料科學及工程學系碩博士班
97
The objet of this study is to synthesize Li3Ba2Gd3(MoO4)8 doped with various activators(Eu3+,Tb3+,Dy3+,Er3+,Sm3+), and the raw material had been mechanically activated by grinding in high energy vibromill followed by calcined at temperature of 900℃ for 12 h. By using XRD, SEM, PL spectra, and UV-visable spectra, the characterization of structure, morphology of powders and photo-luminescent properties of phosphors were analized. The dominant emission peaks of Li3Ba2Gd3(MoO4)8:Eu3+ phosphor are 5D0→7F1(591nm)、5D0 →7F2(614nm) which are originate from intra-4f transitions of excited state. The intensity of the emission from 5D0 to 7F2 is stronger than 5D0 to 7F1 and three times more than commercial phosphors, ZnS:Mn2+,Te2+ when Eu3+ concentration in x=2.4. The CIE chromaticity coordinates of red emission of the Li3Ba2Gd0.6Eu2.4(MoO4)8 phosphor is (0.67, 0.33) which is just at NTSC system standard red chromaticity. There are two regions in the excitation spectra of Li3Ba2Gd2 Tb1(MoO4)8 phosphor;one is assigned from 4f��5d transition in 200 to 300 nm, and the others are from intra-4f transitions in 350 to 500 nm. The dominant emission peak of Li3Ba2Gd2Tb1(MoO4)8 phosphor is 5D4��7F5 under excitation of 307nm. The CIE chromaticity coordinates of green emission of the Li3Ba2Gd2 Tb1(MoO4)8 phosphor is (0.25, 0.58). The the other series of green phosphor is Li3Ba2Gd2.95Er0.05(MoO4)8.Because its emission peaks locates in the light of green region, it has better color rendering index than Li3Ba2Gd2 Tb1(MoO4)8. However, the valence electrons are shielded by the 5s and 5p outer electrons, the valance electrons of trivalent rare earth ions are weakly affected by ligand ions in crystals, so the features of optical spectra of the most phosphors doped with trivalent rare earth, such as Li3Ba2Gd3(MoO4)8:Dy3+ and Li3Ba2Gd3(MoO4)8:Sm3+ is similar to those expected for free ions.
Lee, Szu-Ping, and 李思屏. "The Synthesis, Luminescence Properties, and Applications of Novel Rare Earth-doped Thiosilicate-based Phosphors." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/99210465487605962405.
Повний текст джерела國立交通大學
應用化學系碩博士班
105
The thesis is divided into three parts. Firstly, the study of the blue LED-excitable cyan-emitting, green-emitting, and reddish orange-emitting thiosilicate phosphors. Secondly, the study of the blue LED-excitable cyan-emitting and reddish orange-emitting halothiosilicate phosphors. Finally, the study of the near-UV LED excitable cyan-emitting and green-emitting thiogallates. In Chapter 1, the research background and current status of sulfides and thiosilicates are introduced, and the motivations and goals of this thesis are elaborated. The literature review was focused on the fundamentals of phosphors, concentration quenching of activators, and mechanism of energy transfer of different types of phosphors. In Chapter 2, we describe the synthesis and characterization methods of the thiosilicate phosphors; BaLa2Si2S8:R (R = Ce3+ or Eu2+), CaY2Si2S8:Ce3+, La3Br(SiS4)2:R (R = Ce3+ or Eu2+), BaGa2SiS6:Eu2+, and Ba2Ga8SiS16:Eu2+. In Chapter 3, we discuss the crystal structure and spectroscopic properties of the BaLa2Si2S8:R (R = Ce3+, Eu2+), CaY2Si2S8:Ce3+, La3Br(SiS4)2:R’ (R’ = Ce3+ or Eu2+), BaGa2SiS6:Eu2+, and Ba2Ga8SiS16:Eu2+ phosphors and their LED lighting applications. In Chapter 4, the properties of the thiosilicate phosphors are summarized and the future work is discussed.
CHEN, HONG-RUI, and 陳宏睿. "Enhancement of Red Emission from LiY(MoO4)2 Phosphors Codoped by Rare Earth Elements." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/7saubc.
Повний текст джерела國立臺南大學
材料科學系碩士班
107
In this study, solid state reactions were performed to synthesize a series of lithium yttrium molybdate phosphors, i.e., 1) those co-doped by samarium (Sm) and europium (Eu), 2) those doped by either Sm or Eu, and 3) those not doped. The crystal structure, luminous characteristics, and surface structure of the above- mentioned phosphors were analyzed by means of X-ray diffractometers (XRD), photoluminescence (PL) spectrometers, and scanning electron microscopes (SEM) respectively. XRD analysis shows that both lithium yttrium molybdate phosphors and sodium yttrium molybdate phosphors belong to tetragonal scheelite-type crystallines, and that potassium yttrium molybdate phosphors belong to orthorhombic crystallines. As shown by the PL spectrums, LiY0.96(MoO4)2:4Sm has a strong absorption peak at 407 nm and a dark red emission at 651 nm; in addition, the sintering temperature maintained at 900 °C for 5 hours has the optimal luminous intensity. LiY0.91(MoO4)2:9Eu has two strong absorption peaks at 396 nm and 466 nm, with a strong red emission at 619 nm. Moreover, the sintering temperature maintained at 900 °C for 5 hours has the optimal luminous intensity. Lithium yttrium molybdate phosphors codoped by Sm and Eu display strong absorption peaks at 396 nm, 407 nm and 466 nm, with a strong red emission at 619 nm. Besides, the absorption peak at 466 nm is about two times as high as that at 396 nm. Excited at 466 nm and sintered at 900 °C for 5 hours, LiY0.87(MoO4)2:4Sm, 9Eu shows the optimal luminous intensity. After displacement of Na or K ion, LiY(MoO4)2 excited at 466 nm still has the optimal luminous intensity. SEM analysis shows that, whether doped by one rare earth element or codoped by two rare earth elements, all the phosphors exhibit irregular polyhedral grains and agglomeration. Meanwhile, the phenomenon of agglomeration tends to increase the luminous intensity of red-light phosphors.
Hsu, Fang-Jung, and 許芳榕. "Synthesis and Luminescence Characterizations of New Ultraviolet B&C-Emitting Rare Earth-Doped Phosphors." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/48097170080932342911.
Повний текст джерела國立交通大學
應用化學系碩博士班
102
With the gradual enhancement of environmental awareness, the development of green luminescent materials has been an important issue in phosphors research. This research is attempted to synthesize and investigate new UV-emitting materials, which can be excitated by 172 nm and used for the applications of phototherapy, sterilization, and disinfection. We have explored and investigated the luminescence mechanism of four series of UV-emitting phosphors, including nine types of rare earth-doped phosphates, silicates and borates. In this study, using the vacuum ultraviolet (VUV) light source provided by National Synchrotron Radiation Research Center (NSRRC), as well as the X-ray diffraction technique and electron microscopy analysis, we have prepared and investigated UVB-emitting NaCa(Y,Gd) (PO4)2, Na2(Y,Gd)2O(BO3)2, Li6(Y,Gd)(BO3)3, Na(Y,Gd)Si2O6, NaCa (Y,Pr,Gd)(PO4)2, Li6(Y,Pr,Gd)(BO3)3 and Na(Y,Pr,Gd)Si2O6; UVC- emitting NaCa(Y,Pr)(PO4)2 and Na(Y,Pr)Si2O6. Under excitation at 172 nm, the NaCa(Y,Gd)(PO4)2, Na2(Y,Gd)2O(BO3)2, Li6(Y,Gd)(BO3)3, Na(Y,Gd)Si2O6, NaCa(Y,Pr,Gd) (PO4)2, Li6(Y,Pr,Gd)(BO3)3 and Na(Y,Pr,Gd)Si2O6 phosphors were found to give sharp UVB emission centered at 313 nm, which was attributed to the 4f7→4f7 transition of Gd3+. Under the same excitation, NaCa(Y,Pr)(PO4)2 and Na(Y,Pr)Si2O6 were found to emit UVC light, which was found to be due to the 4f15d1 →4f 2 transition of Pr3+. With the co-doping of Pr3+ as a sensitizer, NaCa(Y,Pr,Gd)(PO4)2, Li6(Y,Pr,Gd)(BO3)3, and Na(Y,Pr,Gd) Si2O6 exhibit a much stronger emission at 313 nm. The emission intensity of the UVB-emitting NaCa(Y0.8293Pr0.0007Gd0.17)(PO4)2, Li6(Y0.695Pr0.005 Gd0.3)(BO3)3 and Na(Y0.775Pr0.005 Gd0.22)Si2O6 was found to be 1.6, 5.4, and 1.4 times that of the UVB emission of the patented LaB3O6:Bi3+,Gd3+ commodity, respectively. Our investigation results indicate that the above three Pr3+/Gd3+-coactivated phosphors may have great potential for practical application in phototherapy and tanning. The luminescence performance of all types of UV radiation was found to be crucially dependent on the chemical compositions, bonding and crystal structure of the host matrix.
Chen, Mu-Jung, and 陳慕蓉. "Synthesis and Luminescence of Novel Rare Earth-Activated Fluorophosphate and Fluorosilicate Phosphors for White-Light Emitting Diodes." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/75163197640627339962.
Повний текст джерела國立交通大學
應用化學系碩博士班
100
In this study, we have successfully synthesized several novel phosphors with compositions of Ca2(Ba1-xEux)3(PO4)3F, (Ca1-xEux)4Si2O7F2, Ca2(Ba1-2x- CexLix)3(PO4)3F, (Ca1-xCex)4Si2O7F2, Ca2(Ba0.99-yCe0.005Li0.005Euy)3(PO4)3F, and (Ca0.998-yCe0.002Euy)4Si2O7F2 by using solid-state method under reducing H2/Ar atmosphere. The crystal structure, luminescence and chromaticity properties of these phosphors were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DR), and photoluminescence spectroscopy. This thesis first reports the optimization of synthetic condition for all phosphors and the analysis of XRD profiles. Then, the spectroscopic properties and thermal-quenching behaviors of Eu2+-doped phosphors were investigated, which were then rationalized by considering nephelauxetic effect and crystal field strength. Furthermore, the luminescence properties and thermal- quenching behaviors of Ce3+-activated phosphors have also been investigated. On the other hand, the Ce3+→Eu2+ energy transfer in systems of Ca2Ba3(PO4)3F: Ce3+, Li+, Eu2+ and Ca4Si2O7F2: Ce3+, Eu2+ were also studied and the energy transfer mechanisms were determined to be the dipole-dipole type interactions. Finally, this thesis discusses the results of all phosphors that we have synthesized and evaluates its applicability in the fabrication of white-LEDs.
Huang, Zih-Cheng, and 黃子誠. "The Synthesis, Characterization and Application of Novel Eu2+ - and Ce3+ -activated Rare Earth Thiosilicate and Halothiosilicate Phosphors." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/9k2u2n.
Повний текст джерела國立交通大學
應用化學系碩博士班
108
In this study, solid-state synthesis was successfully used to prepare nine novel Ce3+ and Eu2+-activated rare earth thiosilicate and halothiosilicate phosphors such as La3X(SiS4)2:Eu2+(X = Cl, I), Y9Al5S21:Ce3+, Ba3AlS4Cl:Eu2+, Y6Al2SiS14:Ce3+, AM(SiS4):Ce3+ (A = K, Cs; M = La, Y), the excitation mainly locates in the near- ultraviolet to the blue region (350 nm-460 nm), the emission locates in the region of blue-green to orange. Our research results provide new choices of phosphors for application in fabrication of white light-emitting diodes (WLEDs). The above-mentioned phosphors were characterized by X-ray diffraction (XRD) and fluorescence spectroscopy to study the phase purity and optimal synthesis conditions and activator doping concentration. In particular, the crystal structure of CsY(SiS4) was determined by the single crystal XRD. Luminescence characterizations were performed to obtain diffuse reflectance spectra, variable temperature PL spectra, quantum efficiency measurement and chromaticity coordinates determination. The first part mainly introduces research background, phosphor design principle and motivations. The second chapter discusses the preparation methods and characteristics of the phosphors developed. The third chapter details the crystal structure and luminescence properties of all phosphors. The fourth chapter summarizes the characteristics of the phosphors for WLEDs fabrication developed in this research and finally discusses the work that can be continued in the future.
Colen, Manaka Mmakgabo. "Synthesis and characterization of long persistent phosphors using combustion method." Diss., 2015. http://hdl.handle.net/10500/20709.
Повний текст джерелаPhysics
M. Sc. (Physics)
Han-YuLin and 林含諭. "The Syntheses and Optical Analyses of Down-Shifting and Up-Conversion Phosphors: Calcium Vanadate-Based Hosts Doped with Trivalent Rare Earth Ions." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/b9mjyj.
Повний текст джерела國立成功大學
電機工程學系碩博士班
101
Our previous work [J. Am. Ceram. Soc., 93, 138 (2010)] reported a red phosphor Ca2.82(VO4)2:0.12Eu3+ which was well-excited by 465-nm blue light and was therefore a candidate for application to the phosphor-converted WLED (pc-WLED) with a blue chip (450-470 nm). On the basis of Ca2.82(VO4)2:0.12Eu3+, we sought to develop down-shifting (DS) inorganic phosphors for use in pc-WLEDs by the commonly-used solid-state reaction method, which was the main purpose of the present research. We found that substitution of not only a larger ion like Ba2+ [J. Am. Ceram. Soc., 93, 138 (2010)] but also a smaller one like Mg2+ (this research) replacing no > 14.9% Ca2+ ions could enhance the integrated DS emission intensity of red phosphor Ca3(VO4)2:0.12Eu3+, indicating that both lattice expansion and contraction could decrease the site symmetry of Eu3+ in Ca3(VO4)2:0.12Eu3+ phosphor. This finding is anticipated to improve the Eu3+ emission intensity of other Eu3+-doped phosphors. To further investigate Eu3+ up-conversion (UC) behaviors, Yb3+ ion was used as a sensitizer. Interestingly, the enhanced Eu3+ emission from 5D1,2,3 states under UC excitation was observed as compared to that under DC excitation. This phenomenon led to the variation in the emission color of the optimized (Ca0.742Mg0.067)2.82(VO4)2:0.36Yb3+,0.12Eu3+ phosphor from red to near warm white as the excitation mechanism changed from DS to UC. Additionally, it was found that substitution of 3% Sr2+ replacing Ca2+ enhanced the red emission intensity of Ca2.82(VO4)2:0.12Eu3+ by 14% under 465-nm excitation. The conventional methods to determine multipolar mechanisms responsible for the energy transfer between different ions (I0/I - C plot) and alike ions (log(C/I) - logC plot) supposed hypotheses of I0/I ≫ 1 and βCθ/3 ≫ 1, respectively, where I0 and I are the emission intensity of the energy donor in the absence and presence of the acceptor; C is the sum of both energy donor and acceptor contents; θ represents the type of multipolar interactions, and β is a constant for each interaction. Compared with the conventional methods, the modified methods for investigation of the multipolar energy transfer proposed in this research demonstrated more precise and valid results. Excluding the prerequisite of I0/I ≫ 1, the concentration-dependent dipole-dipole multipolar interactions for the Sm3+ → Eu3+ energy transfer were observed for the first time based on the fitting results of (I0/I - 1) - C plots. Additionally, the Harris model was found to be an alternative way to release us from the prerequisite of βCθ/3 ≫ 1 when fitting the I/C - C plot. And a dipole-dipole multipolar interaction of 3-body type was found to be responsible for the concentration quenching of Sm3+ emission around 951 nm in the (Ca0.97Sr0.03)3(VO4)2 host.
Nag, Abanti. "Charge-Transfer Associated Photoluminescence Of Rare-Earths Doped Oxide Phosphors." Thesis, 2004. http://hdl.handle.net/2005/335.
Повний текст джерелаYu, Chao-Jung, and 余昭蓉. "The synthesis and characterization of rare-earth doped Y3Al5O12 phosphor powders." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/28619383947181174130.
Повний текст джерела國立交通大學
應用化學研究所
85
This research is attempted to investigate the chemical synthesis and the effects of quantity and types of rare-earth activator (R3+) doping on the structural and luminescent properties of the Y3Al5O12(YAG) phosphors. Well crystalline and x-ray pure powers of R-doped (R=Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) YAG were synthesized by heat treatment of gel-precipitated precursors, first at 300℃ for 3 hours and then at 980℃ for 8 hours. The effects of sntering time and temperature on the purity of R-doped YAG was also investigated to determine the optimal preparation conditions. Cell parameters of R-doped YAG phases as a function of R3+ size were found to decrease, in general, as the atomic number of R increased due to lanthanide contraction, as indicated by x-ray diffraction data. The intensity of luminescent emission for R-doped YAG phase was found to first increase with increasing activator R concentration (i.e., x), then reach a maximum and finally decrease as x further increases. In order to investigate the concentration effect of Sm activator on the spectral properties and color characteristics, we have also prepared a series of (Y3-xSmx)Al5O12 phases with x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, respectively. The cell parameters (a0) of Sm-doped YAG as a function of activator concentration x were discovered to increase with increasing x. This observation was attributed to the larger size of Sm3+ compared to that of Y3+. On the contrary, the intensity of emission spectra of Sm-doped YAG was found to decrease with increasing x. To understand the boundaries of color mixing and compare colors with different intensity values, we have also established CIE chromaticity diagrams for two series of (Y2.95R0.05)Al5O12 and (Y3-xSmx)Al5O12 phosphors, based on the data extracted from photoluminescent emission and excitation spectra.
Chen, Jhih-Hao, and 陳志豪. "Study on KZnPO4 phosphor doped with different rare earth activators (Eu3+,Tb3+,Sm3+,Dy3+)." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/29990435770308492562.
Повний текст джерела崑山科技大學
機械工程研究所
101
The main purpose of this thesis is to develope a new phosphate fluorescent material and to study its characteristics. potassium phosphate zinc (KZnPO4) with hexagonal structure doped with the rare earth ion Eu3+, Tb3+, Sm3+ and Dy3+ as activator was studied in this thesis. Additionally, we investigated the effects of the doping concentration and sintering temperature on the microstructural and optical properties of potassium phosphate zinc (KZnPO4) By X-ray diffraction (XRD), photoluminescence spectrum (PL), and scanning electron microscop (SEM). The results showed that the best doping concentration of the activator Eu3+ is 0.04, the best sintering temperature is 1200 ℃,and the best Package proportion is 1:8. When the Tb3+ activator was doped, the optimum doping concentration is 0.12, the best sintering temperature is 1200 ℃,and the best Package proportion is 1:8. When the Sm3+ activator was doped, the optimum doping concentration is 0.007, the best sintering temperature is 1100 ℃,and the best Package proportion is 1:8. When the Dy3+ activator was doped, the optimum doping concentration is 0.002,the best sintering temperature is 1000 ℃,and the best Package proportion is 1:8.
Chieh-SzuHuang and 黃捷思. "Non-Rare Earth and Fluoride-Free Red Emitting Phosphor: A combined Experimental and Ab Initio Study." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/442f23.
Повний текст джерела國立成功大學
電機工程學系
104
Red light phosphor is the key component for stimulating natural sunlight LEDs. Recent years, Mn4+ luminescence centers are commonly used to substitute environmentally hazardous rare-earth dopants. However, the choice of matrix materials is usually fluoride compound, e.g. K2TiF6, which derivate contaminate issues on silicon industry. In this paper, the ecofriendly “rare-earth-free” and “flouoride-free” red light luminance material, Mg2TiO4 (MTO) with the luminescent center of Mn4+ (MTO:Mn), is investigated. The atomistic models were constructed using ab initio calculations based on density functional theory. The density of states of MTO:Mn with varies potential sensitizers reveal that the best candidate for sensitizer is niobium (Nb). In addition, phosphors were fabricated via solid state sintering. X-ray diffraction spectrum shows no meta-stable phase and photoluminescence spectrum indicates the intensity of light is around 243% after sensitization. This report successfully proposes a novel method to understand optoelectronic properties of phosphors and in turn obtain desirable products. In addition, Mg2TiO4 thin films were as well discussed here. Fabricated by either sol-gel or radio frequency sputtering, annealed at various temperatures and characterized using photoluminescence spectroscopy. Essential physical and optoelectronic properties of the Mg2TiO4 luminance material as well as its optimal processing conditions were comprehensively reported.
CARRASCO, RUIZ IRENE. "Fast emitting oxide scintillators and phosphors." Doctoral thesis, 2017. http://hdl.handle.net/11562/956665.
Повний текст джерелаIn this thesis, various luminescent materials have been prepared and their structural and spectroscopic characterization has been performed in order to test their possible application as phosphors and/or scintillators. The samples under study were oxide based polycrystalline materials (silicates and phosphates) doped with different lanthanide ions. The luminescence properties of Tb3+ and Eu3+ at room temperature and their evolution in the 8 330 K range have been studied in various Tb based silicates with silico carnotite type structure. In the case of Ca3Tb2 xEuxSi3O12, efficient Tb3+ Eu3+ energy transfer has been observed upon UV excitation. Fast energy migration among Tb3+ ions has been found in Ca3Tb2Si3O12 and Ca3Tb2 xEuxSi3O12. A different series of silico carnotite type compounds has been also studied at room temperature. In this case, samples were Gd and Y based materials co doped with Tb3+ and Eu3+. The resulting emission colour of these systems can be modified by controlling the Tb3+/Eu3+ concentration ratio, leading to close to white emission in some of the analysed samples. The effect of the structural changes of the host lattice on the luminescence of Pr3+ has been analysed in two families of phosphates. For the Ca9M(PO4)7 (M = Al, Lu) powders it has been found that the optical properties of the Pr3+ 4f→4f transitions are quite insensitive to the nature of the M cation, but depend strongly on the dopant content: at high Pr3+ concentration the emission from the 1D2 level is quenched due to the presence of cross relaxation processes, whereas no evident changes were observed in the transitions originated in the 3P0 level. In the case of K3Lu1-xYx(PO4)2:Pr3+ samples, it has been found that the emission upon UV excitation is dominated by the 5d→4f intraconfigurational transitions of Pr3+, and that increasing Y content causes the blue shift of the emission band. This shift is linked to the structural changes induced in the host lattice because of the substitution of Lu by Y. Upon X ray excitation the favourable overlap between the defect emission of the host and the Pr3+ 4f→4f transitions causes the progressive variation of the ratio between the 5d→4f and the 4f→4f transitions.
Kuo, Chien-Hung, and 郭建宏. "Environmental Impact and Carbon Footprint Assessment of Rare Earth Recycling Technologies - A Case Study of Recycling Yttrium and Europium From Phosphor." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/22296553767447314842.
Повний текст джерела國立臺北科技大學
環境工程與管理研究所
102
Rare earth elements are the key raw materials of high-tech industries; however, their mining have long been creating lots of environmental impacts ,such as soil erosion, destruction of vegetation and water pollution, etc. Due to the global shortage of rare earth resources, it will be difficult to sustain their long-term supply. Thus, in recent years, rare earth and their supply has become hot issue. Many industrialzed countries have regarded rare earth resources as important strategic resources for economic growth. In light of the facts mentioned above, this study intends to explore the environmental impact and carbon footprints of recovering Yttrium and Europium from phosphor. Two extraction recovery methods, namely acid extraction and solvent extraction, were selected for analysis and comparison. Two LCA commercial softwares were applied and two functional units, same ammounts of phosphor and specific recovery concentrations of Yttrium and Europium, were used. Regarding the acid extraction method, two acidic solutions (H2SO4 and HCl) in two different temperatures (60 ℃, 90 ℃) were used, which were compared with solvent extraction method. Results of acid extracton method showed that the carbon emissions of raw material stage is 58 kgCO2-eq, and the carbon emissions of manufacturing stage are 9.76 kgCO2-eq, 10 kgCO2-eq; 9.26 kgCO2-eq and 9.54 kgCO2-eq for H2SO4, 60 ℃, H2SO4, 90 ℃, HCl, 60 ℃ and HCl, 90 ℃, respectively. For solvent extraction method, the carbon emissions of raw material stage and manufacturing stage are 69 kgCO2-eq and 10.6 kgCO2-eq, respectively. After comparing the carbon emissions of two extraction methods, it is found that although acid extraction method has lower carbon footprints, however, solvent extraction method has much higher extraction efficiency. These results may be used for crafting strategies in implementing life cycle management of rare earth resources for realizing a sustainable use of rare earth resources.
Chung-WeiHsueh and 薛忠偉. "Effect of Baking Treatment on the Change of Rust Structure Formed on High Phosphorous and Rare Earth Containing Weathering Steels." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/86821351048626891546.
Повний текст джерела國立成功大學
材料科學及工程學系碩博士班
98
The structure, morphology, and composition of rust formed after wet/dry cyclic exposure tests and different baking treatments, were determined and analyzed by using SEM、XRD、FTIR、XPS、TGA / DTA and EDS. The steels included carbon steel and weathering steels containing various phosphorus and rare earth elements. Furthermore, rust layer formation mechanism was also discussed. SEM observation showed that the as-formed rust film consisted of two distinct layers. The inner layer was compact while the outer was porous. A more compact rust film was observed with baking, especially for that formed on the steel surface with a higher phosphorus content. XRD, FTIR, and XPS analysis showed that the as-formed and 120 ℃ baking rust consisted of α-FeOOH、γ-FeOOH、amorphous ferric oxyhydroxide and Fe3O4. The results also indicated that α-FeOOH and Fe3O4 were the major species at the inner layer, while γ-FeOOH was dominant at the outer layer. For the steels with higher phosphorous contents, a higher diffraction intensity ratio between α-FeOOH and γ-FeOOH (Iα / Iγ) was found and the formation of β-FeOOH was inhibited. When baked at temperature above 150 ℃, phase transformation in the rust occurred, resulting in the formation of amorphous product. TGA / DTA analysis showed that at a higher baking temperature, dehydrated reaction occurred and phase transformation in the rust occurred, resulting in the formation of amorphous product. EDS analysis showed that P were uniformly distributed within the rust film while rare earth elements almost was not detected. Comprehensively, weathering steels with higher P addition assisted in structure transformation. The morphology and composition were improved, but the effect of rare earth was not remarkable. With baking treatment was above 150 ℃, phase transformation in the rust occurred, resulting in the formation of amorphous product.
Štípek, Radek. "Prvková analýza plochých zobrazovacích zařízení pro urban mining." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-351394.
Повний текст джерела