Articles de revues : « CAZ PHOSPHOR »

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Zhang, Xing Hua, Zun Ming Lu, Fan Bin Meng, Long Hu, Xue Wen Xu, Jing Lin et Cheng Chun Tang. « The Structure and Photoluminescence Properties of Ca₃Si₂O₇ : Eu²⁺Phosphor ». Advanced Materials Research 509 (avril 2012) : 192–96. http://dx.doi.org/10.4028/www.scientific.net/amr.509.192.

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A series of yellow-emitting phosphors based on a silicate host matrix, Ca3-xSi2O7: xEu2+, were prepared by solid-state reaction method. The structure and photoluminescent properties of the phosphors were investigated. The XRD results show that the Eu2+ substitution of Ca2+ does not change the structure of Ca3Si2O7 host. The SEM images display that phosphors aggregate obviously and the shape of the phosphor particle is irregular. The EDX results reveal that the phosphors consist of Ca, Si, O, and Eu elements. The Ca3-xSi2O7: xEu2+ phosphors can be excited at wavelength of 300-490 nm, which is suitable for the emission band of near ultraviolet or blue light-emitting-diode (LED) chips. The phosphors exhibit a broad emission region from 520 to 650 nm and the emission peak centered at 568 nm. The phosphor for has the strongest excitation and emission intensity, and the energy transfer style between Eu2+ ions is quadrupole-quadrupole interaction for higher concentration Eu2+ doped Ca3Si2O7 phosphor. The Ca3-xSi2O7: xEu2+ phosphors can be used as candidates for white LEDs.

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MORI, KENTAROU, YOSHIYUKI KOJIMA et NOBUYUKI NISHIMIYA. « EFFECT OF REDUCING ATMOSPHERE ON THE AFTERGLOW PROPERTIES OF RED-EMITTING CaS:Eu2+,Pr3+ PHOSPHORS ». Functional Materials Letters 05, n^o 02 (juin 2012) : 1260012. http://dx.doi.org/10.1142/s1793604712600120.

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The afterglow time of typical red-emitting phosphors is much shorter than those of green- or blue-emitting phosphors which afterglow time were longer than 1000 min. CaS has been used as an effective host material for afterglow phosphors because trapping centers can be easily created in the host by doping with an activator. This study reports on the effect of a reducing atmosphere on the afterglow properties of a red-emitting CaS:Eu2+,Pr3+ phosphor. The phosphor was prepared by reduction under an Ar-H2 (5%) or H2S atmosphere from a CaSO4:Eu3+,Pr3+ phosphor prepared using a liquid phase method. Heating the CaSO4:Eu3+,Pr3+ phosphor for 2 h under an Ar-H2 (5%) atmosphere at 1050°C gave CaO as by-product in addition to CaS . The resulting phosphor exhibited red-emission at 646 nm originating from Eu2+ ions upon visible light irradiation, and gave some afterglow after cessation of visible light irradiation. Addition of Li+ ions extended the afterglow time of the phosphor as a result of a slight change in the CaS host structure. For preparation of a CaSO4:Eu3+,Pr3+ phosphor under a H2S atmosphere, a CaS monophase was obtained. The emission and afterglow of the phosphor were similar to that prepared under the Ar-H2 (5%) atmosphere, but the afterglow time resulting from the CaS monophase was longer. The longest afterglow time obtained was about 60 min for a phosphor prepared under a H2S atmosphere with an initial Li/Ca atomic ratio of 0.04.

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Liu, Sheng, Bei Ying Zhou, Shi Jia Gu, Lian Jun Wang, Wan Jiang et Wei Luo. « A Promising Energy-Saving and Environmental-Friendly Lighting Device : High CRI White LED with Phosphor Materials ». Materials Science Forum 848 (mars 2016) : 446–53. http://dx.doi.org/10.4028/www.scientific.net/msf.848.446.

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Two kinds of commercial LED phosphors (green phosphor LuAG:Ce3+ and red phosphor CaAlSiN3:Eu2+) with polymethyl methacrylate (PMMA) powders were mixed to prepare film phosphors with tunable emission peak in photoluminescence spectrum by flat vulcanizing machine under the temperature of 170 oC and pressure of 2 MPa. The physical phase, surface morphology, transmittance, luminescence spectra of samples were characterized by means of X-ray diffraction (XRD), Environmental scanning electron microscopy (ESEM), Ultraviolet-Visible (UV-Vis) spectrophotometry and Fluorescence spectrometer. The results show that the film phosphors phase was consistent with raw phosphors, phosphor particles were uniformly distributed, and fluorescence spectra with different proportions of phosphors in different position can be adjusted. Tested by HSP 3000 spectrum analyzer, the white LEDs fabricated by blue chip and composite film phosphor containing 5 wt% green phosphor and 1.5 wt.% red phosphor, which refers to the remote excitation technique, possessed color coordinate of (0.3715, 0.3280) and color rendering index (CRI) of 87 when it was driven at power of 36 V/140 mA, reaching the international advanced level.

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Ye, Shenrui, Yukun Li, Ming Qiang, Wenhui Lou, Bo Dai, Hui Lin, Zhaoxia Han, Ruijin Hong et Dawei Zhang. « Color Tunable Composite Phosphor Ceramics Based on SrAlSiN3:Eu2+/Lu3Al5O12:Ce3+ for High-Power and High-Color-Rendering-Index White LEDs/LDs Lighting ». Materials 16, n^o 17 (31 août 2023) : 6007. http://dx.doi.org/10.3390/ma16176007.

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Lu3Al5O12:Ce3+ phosphor ceramics were fabricated by vacuum sintering. On this basis, a bi-layer composite phosphor was prepared by low-temperature sintering to cover the phosphor ceramics with a layer of SrAlSiN3:Eu2+-phosphor-in-glass (PiG). The optical, thermal, and colorimetric properties of LuAG:Ce3+ phosphor ceramics, SrAlSiN3:Eu2+ phosphors and SrAlSiN3:Eu2+-PiG were studied individually. Combining the bi-layer composite phosphors with the blue LED chip, it is found that the spectrum can be adjusted by varying the doping concentration of SrAlSiN3:Eu2+-PiG and the thickness of Lu3Al5O12:Ce3+ phosphor ceramics. The maximal color rendering index value of the white LED is 86, and the R9 is 61. Under the excitation of a laser diode, the maximum phosphor conversion efficacy of the bi-layer composite phosphors is 120 lm/W, the Ra is 83, and the correlated color temperature is 4534 K. These results show that the bi-layer composite phosphor ceramic is a candidate material to achieve high color rendering index for high brightness lighting.

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Rodionova, Anna V., Victor I. Kuular, Tamara S. Minakova, Parviz Sh Ustabaev et Vadim V. Bakhmetyev. « Acid-Base and Luminescent Properties of Gd₂O₂S : Tb Luminescent Phosphors Synthesized in a Reducing Atmosphere ». Key Engineering Materials 854 (juillet 2020) : 57–63. http://dx.doi.org/10.4028/www.scientific.net/kem.854.57.

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Gd2O2S:Tb phosphors with different terbium content are prepared in a reducing atmosphere at various synthesis conditions. The effect of an activator and Na4P2O7 flux concentrations upon photo-and X-ray induced luminescence of the synthesized samples as well as on their acid-base properties and morphology is studied. The addition of Na4P2O7 flux into the charge mixture leads to a significant increase of the phosphor particle size. A positive correlation is found between the particle size and pH value of the phosphor aqueous slurry. The photoluminescence intensity is found to mostly depend on the activator concentration, while X-ray luminescence intensity primarily depends on the particle size and crystal structure perfectness of the phosphor matrix. Charge mixture compositions and synthesis conditions providing Gd2O2S:Tb phosphors with the highest photo-and X-ray luminescence intensity are determined. A Gd2O2S:Tb phosphor with X-ray luminescence intensity exceeding the values for the commercial phosphor KEP-45 of a similar composition is developed. The obtained phosphors can be used for the manufacture of intensifying screens applied in industrial X-ray flaw detection.

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Tatte, S. P., N. S. Dhoble, G. C. Mishra et S. J. Dhoble. « Synthesis characterization and Luminescence Properties of B₂BiMg₂V₃O₁₂ based phosphors with rare earth activated Dy³⁺ phosphor for solid state lighting ». IOP Conference Series : Materials Science and Engineering 1258, n^o 1 (1 octobre 2022) : 012016. http://dx.doi.org/10.1088/1757-899x/1258/1/012016.

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Highly new efficient vanadate based phosphor B2BiMg2V3O12 (B= K & Na) material incapacitated through rare-earth Dysprosium (Dy) and it was characterized by high temperature solid-state synthesis. Equipped phosphor was established by X-ray diffraction method. In Photo-luminescence measurements shows that the prepared phosphors doped by Dy is excited by near UV ultraviolet light reaching after 300 nm to 380 nm efficiently acceptable to recognize the emission in visible spectrum (in the range 400 nm –570 nm. The highly efficient prepared phosphor doped with lanthanide doped with Dy phosphor likewise showed the exact emission point at 487 nm and 571 nm at the excitation point at 325 nm. Hence, these prepared phosphors can find numerous applications as green emitting phosphor in the field of solid-state lighting area.

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Chen, Yi Bo, Wei Cai, Yong Qiao Liu et Meng Lian Gong. « Ca₃Sc₂Si₃O₁₂:1%Ce³⁺, x%Ba²⁺ Green Phosphors for White Light-Emitting Diodes ». Advanced Materials Research 557-559 (juillet 2012) : 776–80. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.776.

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Low temperature-quenching and high-efficiency Ca3Sc2Si3O12:1%Ce3+, x%Ba2+ phosphors were prepared by solid state method and the properties of these phosphors were investigated. The results showed that co-doping of Ba2+ ions can improve the photoluminescence properties and decrease temperature-quenching of Ca3Sc2Si3O12:Ce3+ phosphor obviously. High-efficiency blue-green light-emitting diode was fabricated with the prepared phosphor and an InGaN blue-emitting (~460 nm) chip. Good performance of the prepared LED indicates that Ca3Sc2Si3O12:1%Ce3+, 0.5%Ba2+ phosphor is a suitable candidate for the fabrication of high-efficiency white LEDs.

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Segal, Ohad, Avner Shultzman, Yaniv Kurman et Ido Kaminer. « Optimizing the spontaneous-emission of far-UVC phosphors ». Applied Physics Letters 120, n^o 23 (6 juin 2022) : 231902. http://dx.doi.org/10.1063/5.0092109.

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Far-UVC light can enable virus-deactivation while remaining harmless to human tissues. This triggered great efforts to create far-UVC light sources with sufficient emission power and efficiency. However, current sources, such as mercury lamps, KrCl excimer lamps, and LEDs, are made from hazardous chemicals or are limited by low efficiency. Consequently, an alternative approach for reaching the far-UVC is now receiving renewed interest: using phosphors for converting higher frequencies to the desired range of far-UVC. However, this concept is limited by the phosphor's conversion efficiency. In this paper, we propose to utilize principles of nanophotonics to create far-UVC sources. Specifically, we design a phosphor-dielectric multilayer that increases the efficiency of far-UVC light conversion and controls the intrinsic emission properties, including the angular spectrum and emission rate, by shaping the local density of photonic states. To exemplify our approach, we design an aperiodic multilayer nanostructure made of the phosphor material YPO4:Pr3+, showing an increase in light extraction by a factor of 3 compared to naïve bulk structures. Our approach can be applied to any phosphor material and any emitter geometry, opening avenues for engineering nanophotonic light sources in the far-UVC and other spectral regimes.

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Yadav, Pooja J. « Long Persistent Afterglow Luminescence in Gd3Al3Ga2O12 ;:Ce3+, Green Emitting Aluminate Phosphor ». Materials Science Forum 1072 (25 octobre 2022) : 163–68. http://dx.doi.org/10.4028/p-t5bm75.

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Green LL is observed in Ce doped Gd3Al5O12: Ce, Ga garnet phosphors. LL is well correlated with Ce3+ emission and a peak around 150°C in the TL glow curve. In comparison with the commercial phosphor YAG, the Gd3Al5O12: Ce, Ga (GAG) is more stable and shows more intense TL properties, this phosphor can be used for dosimetry detections and measurements. Gd3Al5O12 activated with Ce (0.7 mol.%) phosphors were prepared by combustion synthesis. The long-lasting luminescence (LL) is also reported in Pr3+ and Ce3+ doped in reducing atmosphere in YAG phosphor. But YAG: Ce gives yellow emission which doesn’t suit LL applications. On the other hand, Ga substituted GdAG: Ce phosphor gives green emission at shorter wavelengths. In this paper we explored Ga substituted GdAG: Ce phosphor prepared by combustion synthesis for LL, results of these investigations are reported in this paper.

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Sun, Jia Yue, Jin Li Lai et Hai Yan Du. « Synthesis and Luminescence Properties of Red Emitting Phosphors Na₃CaB₅O₁₀:Eu³⁺ ». Advanced Materials Research 295-297 (juillet 2011) : 547–50. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.547.

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A series of new Na3CaB5O10:Eu3+ phosphor was synthesized by a solid-state reaction method, and its luminescent properties were investigated. The phase formation of phosphors was confirmed by X-ray powder diffraction (XRD). The excitation spectra exhibited that the phosphors could be effectively excited by near ultraviolet (392 nm) and blue (464 nm) light, which perfectly match the emission wavelength of near-UV light-emitting diodes (LEDs). The emission spectra showed that two characteristic red emission lines peaking at 592 and 613 nm can be obtained upon 394 and 463 excitation with the chromaticity coordinates of (0.6347, 0.3649), which are due to 5D0- 7F1 and 5D0-7F2transitions of Eu3+ ions. The effect of Eu3+ concentration on the emission spectrum of Na3CaB5O10:Eu3+ phosphor was studied. The results showed that the emission intensity increased with increasing Eu3+ concentration, and then decreased because of concentration quenching. The obtained results indicated that this phosphor could be a promising candidate for near-UV white LEDs.

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Rao, Ch Atchyutha, N. Bujji Babu et K. V. R. Murthy. « Synthesis and Optical Properties of Ce3+ Doped Gadolinium Silicate Phosphors ». European Journal of Theoretical and Applied Sciences 1, n^o 4 (6 juillet 2023) : 1288–95. http://dx.doi.org/10.59324/ejtas.2023.1(4).118.

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The present paper reports the optical properties of rare-earth-doped Gadolinium Silicate Phosphors. The Cerium Oxide (Ce3+) was used as rare-earth-doped. The phosphor is prepared by using the Solid-state reaction method (conventional method) heated at 1200oC for 2 hrs. The received cakes are grounded for 30 minutes each. The phosphors are prepared and the received powder is subjected to PL, XRD, SEM, and EDAX analysis. The following section discusses and the experimental results are mentioned in these phosphors. The present Phosphor can act as a host for blue light emission in many display devices and technological applications.

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Зуев, С. М., et А. В. Кретушев. « Исследование микроструктуры люминофоров для лазерных осветительных устройств ». Оптика и спектроскопия 131, n^o 3 (2023) : 370. http://dx.doi.org/10.21883/os.2023.03.55387.4616-22.

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A brief description is given of phosphors from various manufacturers that can be used in lighting devices with laser injection in the range of 400–480 nm. An estimate of their energy output and inertia is given. The necessity of studying various types of luminescence to optimize the characteristics of phosphor lighting devices is described. It is known that the optical characteristics of laser lighting devices depend on the quality of the phosphor. However, at the moment there are no well-established methods for studying phosphors for compliance with the requirements for brightness, luminous flux, and thermal degradation. One of these methods can be microscopy, which allows you to study the microstructure of samples. The paper considers a method for determining the geometric and optical parameters of individual phosphor particles used for laser lighting devices using microscopy. On the example of a fine suspension of phosphors, images were obtained and some optical parameters of individual particles with diameters from 40 to 150 nm were determined. The conducted studies demonstrate the high resolution of the microscopy method, which can be used to visualize phosphor particles.

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Yin, Peng, Can Xue et Bin Guo. « Surface modification model of long afterglow phosphors by saturated fatty acid based Al-Zr coupling agent ». Pigment & ; Resin Technology 45, n^o 5 (5 septembre 2016) : 330–34. http://dx.doi.org/10.1108/prt-07-2015-0060.

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Purpose The purpose of this paper is to study the influence of different carbon chain lengths in coupling agents on the water resistance and compatibility of modified long afterglow phosphors and attempt to obtain their modification model and mechanism. Design/methodology/approach Three saturated-fatty-acid (caprylic, lauric, stearic acid)-based Al-Zr CAs (coupling agent) was synthesised and applied to modify the long afterglow phosphors SrMgAl4O8:Eu2+,Dy3+. Findings Results show that the coated amount on phosphors decreased from 13.41 to 6.53 per cent with the increased carbon chain length of fatty acid, and the better water resistant and suitability with organic resin can be obtained by lauric-based Al-Zr CA. Originality/value Considering that the decomposition process of modified phosphor was related with the decomposition performance of corresponding coupling agents and original phosphor, a method was first proposed to calculate the coated amount on phosphors by thermogravimetric analyser parameters.

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Jia, Lin Yan, Zhong Bao Shao et Jun Feng Han. « Luminescence Properties of ZnO:Eu³⁺ Red Emitting Phosphor Prepared by Precipitation Method ». Advanced Materials Research 690-693 (mai 2013) : 594–97. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.594.

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Zinc oxide doped with Eu3+ ions red emitting phosphors were prepared by precipitation method, and its luminescence properties were investigated. The phosphors were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectra. The ZnO:Eu3+ phosphors were obtained at 600°C by calcining precipitation precursor. These phosphors can be effectively excited at 465nm. In emission spectra, the strongest peak at 616nm correlating to red emission is due to the electric dipole transition 5D07F2 of Eu3+ ions. Eu3+ions replaced Zn2+ ions and occupied the non-centrosymmetric sites in the ZnO matrix lattice. The phosphor particles with narrow distribution range are approximately 100-200nm in size. The luminescence properties of ZnO:Eu3+ phosphor with 8 mol% doping concentration of Eu3+ is optimal.

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Atchyutha Rao, Ch, et K. V. R. Murthy. « SYNTHESIS, CHARACTERIZATION AND PHOTOLUMINESCENCE PROPERTIES OF EU3+DOPED CALCIUM SILICATE PHOSPHOR BY CONVENTIONAL SOLID STATE REACTION METHOD ». International Journal of Advanced Research 8, n^o 12 (31 décembre 2020) : 762–69. http://dx.doi.org/10.21474/ijar01/12209.

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Calcium Silicate phosphor acquires a higher luminous efficiency when it is doped with rare earth activated ions. Silicate phosphors are used for a fluorescent, a cathode-ray tube, a luminous body, a vacuum ultraviolet excitation light emitting element etc. The silicates of calcium are known for their thermal stability, high temperature strength, low thermal expansion, cheep residence and chemical inertness. The present paper reports on the synthesis, characterization and photoluminescence properties of Eu3+ doped calcium silicate phosphor prepared by conventional solid state reaction method heating at 12000C for 3 hrs. The received cakes are grounded for 30 minutes each. The phosphors are prepared and the received powder is subjected to PL, XRD, SEM, EDAX and CIE analysis. The following section discusses and the experimental results are mentioned in these phosphors. The present Phosphor can act as a host for red light emission in many display devices and technological applications.

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Atchyutha Rao, Ch, et K. V. R. Murthy. « SYNTHESIS, CHARACTERIZATION AND PHOTOLUMINESCENCE PROPERTIES OF EU3+DOPED CALCIUM SILICATE PHOSPHOR BY CONVENTIONAL SOLID STATE REACTION METHOD ». International Journal of Advanced Research 8, n^o 12 (31 décembre 2020) : 762–69. http://dx.doi.org/10.21474/ijar01/12209.

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Calcium Silicate phosphor acquires a higher luminous efficiency when it is doped with rare earth activated ions. Silicate phosphors are used for a fluorescent, a cathode-ray tube, a luminous body, a vacuum ultraviolet excitation light emitting element etc. The silicates of calcium are known for their thermal stability, high temperature strength, low thermal expansion, cheep residence and chemical inertness. The present paper reports on the synthesis, characterization and photoluminescence properties of Eu3+ doped calcium silicate phosphor prepared by conventional solid state reaction method heating at 12000C for 3 hrs. The received cakes are grounded for 30 minutes each. The phosphors are prepared and the received powder is subjected to PL, XRD, SEM, EDAX and CIE analysis. The following section discusses and the experimental results are mentioned in these phosphors. The present Phosphor can act as a host for red light emission in many display devices and technological applications.

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Wang, Jun-Feng, Hao Zu, Chuan-Wen Lin, Shou-Jun Ding, Peng-Yu Shao et Ye Xia. « Synthesis and Luminescence Properties of SrGd2O4:Eu3+ Red Phosphors ». International Journal of Optics 2020 (14 avril 2020) : 1–5. http://dx.doi.org/10.1155/2020/3095429.

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As one of the important raw materials for LED products, phosphors play an important role. At present, the spectrum of LED phosphors lacks red light, resulting in poor quality of white LED products and a low color rendering index (Ra <80), which affects lighting effects. To solve this problem, we synthesized the SrGd2O4:Eu3+ red phosphor by a high-temperature solid-phase method. The structure and luminescence properties of SrGd2O4:Eu3+ red phosphors were studied by means of X-ray diffraction (XRD) measurements of their emission and excitation spectra, and their spectra were analyzed. We also studied the Eu3+ doping concentration with the best luminous efficiency and the color coordinate of the SrGd2O4:Eu3+ phosphor. The experimental results show that SrGd2O4:Eu3+ is a new red phosphor material that can be used for near-ultraviolet or blue-light excitation and has good practicability.

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Gawande, A. B., R. P. Sonekar et S. K. Omanwar. « Synthesis and Photoluminescence Study of Bi3+and Pb2+Activated Ca3(BO3)2 ». International Journal of Optics 2014 (2014) : 1–6. http://dx.doi.org/10.1155/2014/418459.

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The photoluminescence properties of Pb2+and Bi3+doped Ca3(BO3)2prepared by solution combustion synthesis technique are discussed. The structure of the prepared phosphor is characterized and conformed by XRD and FTIR. SEM images of the prepared materials show irregular grains with agglomerate phenomena. Prepared phosphors achieved the band emissions, respectively, at 365 nm and 335 nm corresponding to the transitionP1→S013. Optimum concentration, critical transfer distance, and Stokes shift of the synthesized materials were measured. These phosphors may provide an efficient kind of luminescent materials for various applications in medical and industry.

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Baig, Nahida, N. S. Dhoble, N. S. Kokode et S. J. Dhoble. « Photoluminescence Properties of Eu3+ and Ce3+ Activated Calcium Chlorophosphate Via Combustion Synthesis Method ». Oriental Journal of Physical Sciences 1, n^o 1-2 (24 août 2016) : 10–15. http://dx.doi.org/10.13005/ojps01.0102.03.

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Calcium chlorophosphate (Ca2PO4Cl) phosphors, activated by rare earth ions Eu3+ and Ce3+ were prepared by urea assisted combustion synthesis technique and their characterization and luminescent properties were studied. The synthesized phosphors were investigated by powdered XRD, SEM and Photoluminescence characterization (PL) methods. PL excitation spectra of Ca2PO4Cl:Eu3+/Ce3+ phosphor exhibit narrow bands in the near ultra violet (n-UV) range, and the PL emission spectra of Ca2PO4Cl: Eu3+/Ce3+ phosphor shows sharp narrow bands typical of rare earth ions. The bands observed in the PL emission and excitation spectra of Ca2PO4Cl: Eu3+/Ce3+ phosphors can be ascribed to the electronic transitions within 4f configurations of rare earth ions. The excitation peaks for Ca2PO4Cl: Eu3+ is in n-UV range. The obtained results suggest that these phosphors may be favorable for lamp industry.

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Zheng, Jianghui, Jia Feng, Qijin Cheng, Ziquan Guo, Lihan Cai et Chao Chen. « A novel high color purity yellow luminescent material NaBaBO3:Sm3+ ». Functional Materials Letters 08, n^o 04 (août 2015) : 1550042. http://dx.doi.org/10.1142/s1793604715500423.

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Yellow emitting Sm 3+-doped NaBa 1-x BO 3(0.01 ≤ x ≤ 0.13) phosphors were synthesized by conventional solid state reaction method. The phase structure and luminescence properties of the as-prepared phosphors were investigated. These phosphors can be effectively excited by 403 nm near-ultraviolet light and feature a satisfactory yellow performance. The emission peaks are observed at 560 nm, 603 nm and 650 nm, originating from the transitions of 4G5∕2→6H5∕2, 4G5∕2→6H7∕2 and 4G5∕2→6H9∕2 respectively. Investigation of Sm 3+ concentration-dependent emission spectra indicates that the NaBa 0.95 BO 3:0.05 Sm 3+ phosphor shows the strongest yellow emission intensity and exhibits the CIE value of x = 0.4760 and y = 0.5090. Through the theoretical calculation, a high color purity of 96.0% was determined for the NaBaBO 3: Sm 3+ phosphor, and the color purity of NaBaBO 3: Sm 3+ is much higher than that of the commercial yellow phosphor YAG : Ce 3+. This work is highly relevant to the development of a new type of potential down-conversion (DC) yellow phosphor for near ultraviolet white or yellow light-emitting diodes (LEDs).

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Wang, Haifeng, Jianwei Lu, Ruoxuan Wang, Yungu Dong et Linfeng Ding. « Synthesis and Characterization of the CaTiO3:Eu3+ Red Phosphor by an Optimized Microwave-Assisted Sintering Process ». Materials 13, n^o 4 (15 février 2020) : 874. http://dx.doi.org/10.3390/ma13040874.

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The synthesis process has a significant influence on the properties of Ca1-xTiO3:Eu3+x phosphors; thus, an optimized process will lead to a better performance of the Ca1-xTiO3:Eu3+x phosphors. In this work, the feasibility of synthesizing the Ca1-xTiO3:Eu3+x phosphor with a good luminescent performance by combining the chemical co-precipitation method and microwave-assisted sintering was studied. The precursor of Ca1-xTiO3:Eu3+x phosphors were prepared by the chemical co-precipitation method. To find an optimized process, we applied both of the traditional (furnace) sintering and the microwave-assisted sintering to synthesize the Ca1-xTiO3:Eu3+x phosphors. We found out that a sintering power of 528 W for 50 min (temperature around 950 °C) by a microwave oven resulted in similar emission intensity results compared to traditional furnace sintering at 900 °C for 2.5 h. The synthesized Ca1-xTiO3:Eu3+x phosphors has an emission peak at 617 nm (5D0→7F2), which corresponds to the red light band. This new synthesized method is an energy efficient, time saving, and environmentally friendly means for the preparation of Ca1-xTiO3:Eu3+x red phosphor with good luminescent performance.

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Kousaka, Shinichiro, Kenji Toda, Tadashi Ishigaki, Kazuyoshi Uematsu et Mineo Sato. « Development of New Red Phosphor Na₃YSi₂O₇:Eu³⁺ for a White LED ». Key Engineering Materials 421-422 (décembre 2009) : 360–63. http://dx.doi.org/10.4028/www.scientific.net/kem.421-422.360.

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New red phosphors Na3YSi2O7:Eu3+ was prepared by a conventional solid-state reaction. This silicate phosphor can be efficiently excited by near UV light, yielding an intense red emission. Under the excitation of near UV light, the emission intensity is higher than that of a commercial red phosphor Y2O2S:Eu3+.

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Lu, Juan, Chia-Ching Su, Cheng-Shong Hong, Guoxiang Peng et Cheng-Fu Yang. « Investigations of Photoluminescence Properties of CaxMg2-xSi2O6:yEu2+ (x = 0.5–1.25, y = 0.015–0.035) Phosphors ». Materials 16, n^o 5 (1 mars 2023) : 2032. http://dx.doi.org/10.3390/ma16052032.

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Previously, there were almost no relevant studies on developing the optimal CaxMg2-xSi2O6:yEu2+ phosphor composition for its finest optical properties. This study employs two steps to determine the optimal composition for CaxMg2-xSi2O6:yEu2+ phosphors. First, CaMgSi2O6:yEu2+ (y = 0.015, 0.020, 0.025, 0.030, 0.035) was used as the primary composition of specimens synthesised in a reducing atmosphere of 95% N2 + 5% H2 to investigate the effect of Eu2+ ions on the photoluminescence properties of each variant. The emission intensities of the entire photoluminescence excitation (PLE) and photoluminescence (PL) emission spectra of the CaMgSi2O6:yEu2+ phosphors initially increased as the concentration of the Eu2+ ions increased, peaking at y = 0.025. The cause of the variations across the entire PLE and PL spectra of all five CaMgSi2O6:yEu2+ phosphors was investigated. Because the CaMgSi2O6:0.025Eu2+ phosphor had the highest PLE and PL emission intensities, in the next step, CaxMg2-xSi2O6:0.025Eu2+ (x = 0.5, 0.75, 1.0, 1.25) was used as the primary composition to investigate the effect on the photoluminescence properties when the CaO content varied. We also show that the Ca content has an apparent effect on the photoluminescence properties of CaxMg2-xSi2O6:0.025Eu2+ phosphors, and the optimal phosphor composition is Ca0.75Mg1.25Si2O6:0.025Eu2+ because it has the largest PLE and PL values. X-ray diffraction (XRD) analyses of CaxMg2-xSi2O6:0.025Eu2+ phosphors were performed to identify the factors responsible for this outcome.

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Yan, Jun Ping, Zi Long Tang, Shao Hua Luo et Zhong Tai Zhang. « Surface Modification of Long Afterglow Sr₄Al₁₄O₂₅ : Dy,Eu Phosphor by Silica Coating ». Key Engineering Materials 280-283 (février 2007) : 509–12. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.509.

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In order to improve water resistance of phosphors and the stability of particles in aqueous suspensions, the phosphor particles were coated with varying amounts of silica via the hydrolysis of tetraethyl orthosilicate. The composite particles were characterized by transmission electron spectroscopy, BET N2 gas adsorption, sedimentation time studies and fluorescent spectrometer. The specific surface area of the silica-coated phosphor particles showed a non-systematic increase. In comparison to the uncoated phosphor (3.65m2/g), silica coatings of 13, 25, 50, 75wt% yielded specific surface areas of 15.19, 14.29, 37.90 and 226.12 m2/g respectively. This behavior can be explained based on a heterocoagulation coating mechanism in which silica clusters adsorb onto the phosphor particles surface. The sedimentation data display the stability of the coated particles improved as the silica content increased. The excitation and emission spectra show that the luminescent properties of the phosphors are unimpaired or even better. The optimum luminescent properties obtained when coating 50wt% silica after calcining at 400oC.

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Du, Jiang Nan, Deng Hui Xu, Zai Fa Yang, Xue Dong Gao et Jia Yue Sun. « Preparation and Luminescence Properties of Dy³⁺ Doped Sr₃Lu(PO₄)₃ as a New Single Phase White Light Emitting Phosphor ». Key Engineering Materials 727 (janvier 2017) : 612–17. http://dx.doi.org/10.4028/www.scientific.net/kem.727.612.

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The novel white light emitting phosphors Sr3Lu(1-x)Dyx(PO4)3 (x = 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized via a conventional high-temperature solid-state reaction method at 1250°C. The excitation spectrum indicated that these phosphors had a strong absorption in near UV region in the range from 260 to 460 nm. And under 350 nm excitation, the blue emission at 483nm (4F9/2→6H15/2) and yellow emission at 576 nm (4F9/2→6H13/2) were observed in the phosphors, respectively. We studied the effect of different doping concentrations of Dy3+ activator on the luminescence properties and found that the optimum doping concentration is 6 mol%. According to the Dexter’s theory, this quenching behavior is ascribed to be electric d-d interaction. Furthermore, the chromaticity coordinate (x = 0.28, y = 0.32) of Sr3Lu (PO4)3:0.06Dy3+ phosphor was very close to the “ideal white” (x = 0.33, y = 0.33) in the chromaticity diagram. Our results indicate that the Sr3Lu (PO4)3:Dy3+ phosphor can serve as a promising candidate for single-component white light emitting phosphor under near UV excitation.

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Yerojwar, R. M., N. S. Kokode, C. M. Nandanwar et D. K. Ingole. « Synthesis and Photoluminescence characterization of Sr3La(AlO)3(BO3)4:Eu3+,Sm3+ Phosphor for W-LED ». Physics and Chemistry of Solid State 24, n^o 1 (27 mars 2023) : 202–7. http://dx.doi.org/10.15330/pcss.24.1.202-207.

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A Red emitting with high efficiency Eu3+ doped Sr3La(AlO)3(BO3)4 and Sm3+ doped Sr3La(AlO)3(BO3)4 phosphors has been synthesized by combustion method, meanwhile, the photoluminescence properties of samples are investigated in detail. Morphology by SEM and chromaticity by CIE was studied. The results show that the excitation extends from 340 nm to 420 nm, with the highest excitation (394 nm and 406 nm) being in the violet area for Eu3+ and Sm3+ doping, indicating that the phosphor can correlate well with LED chips. Under violet light excitation of 394nm the phosphor Eu3+ doped Sr3La(AlO)3(BO3)4 and of 406 nm the phosphor Sm3+ doped Sr3La(AlO)3(BO3)4 can emit strong red light showing main emission peaks located at 617 nm and 602 nm are observed respectively. The PL properties implies the excellent stability of the phosphor. These results imply that the importance red phosphors Sr3La(AlO)3(BO3)4:Eu3+ and Sr3La(AlO)3(BO3)4:Sm3+ in W-LEDs under NUV excitation.

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Zhang, Xiao Qi, Li Min Dong, Xin Cheng Tang, Qin Li et Zhi Dong Han. « Preparation and Luminescent Properties of Single White Ca₂MgSi₂O₇ : Eu³⁺, Ce³⁺, Tb³⁺ Phosphor for WLED ». Advanced Materials Research 989-994 (juillet 2014) : 395–98. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.395.

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Ca2MgSi2O7: Eu3+, Ce3+, Tb3+, a single white Phosphor, was synthesized by the conventional solid-state reaction. The structure, surface morphology and luminescence properties of the prepared samples were investigated to evaluate its potentiality. XRD results confirm the orthorhombic phase of Ca2MgSi2O7: Eu3+, Ce3+, Tb3+ phosphors. The excitation spectra indicates the phosphor can be excited by 393 nm wavelength. The phosphor exhibits blue light at 467 nm, green light at 588 nm, red light at 618 nm. CIE chromaticity diagram indicates that Ca2MgSi2O7: Eu3+, Tb3+, Ce3+ exhibits white light. All properties show that the prepared phosphor is a single white phosphor suitable for near ultraviolet excitation which can be applied to new generation white LED lighting.

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Devi, Y. Rangeela, et S. Dorendrajit Singh. « Annealing effect on thermoluminescence (TL) glow curve of Ca0.99SO4:Eu0.005Dy0.005phosphor ». Science Vision 18, n^o 1 (31 mars 2018) : 32–36. http://dx.doi.org/10.33493/scivis.18.01.05.

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Ca1-x-ySO4:Eux,Dyy (0 < x < 0.04, 0 < y < 0.04) phosphors were prepared and characterized by XRD. The samples were well crystalline and exhibit orthorhombic structure. The phosphor Ca0.99SO4:Eu0.005Dy0.005 was found having highest TL intensity. The phosphor was annealed at different temperatures. All the TL glow curves have one prominent peak at 420K. TL intensity for this peak was found decreasing when the phosphor was annealed at a particular temperature for different durations.

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Chen, Bi Sang, Zi Shan Zheng, Yan Mei Lin, Guo Liang Chen, Liang Zhou, Hong Xu Guo et Ling Feng Huang. « Preparation of a Novel Red Long Lasting Phosphorescent Material CaAl₂Si₂O₈:Mn²⁺ and Investigation of its Luminescent Properties ». Applied Mechanics and Materials 71-78 (juillet 2011) : 3151–55. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.3151.

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A novel red long-lasting phosphor CaAl2Si2O8:Mn2+ was successfully synthesized by sol-gel method. X-ray diffractometer(XRD) and fluorescence spectrometer were used to characterize the structure and photoluminescence of the persistent phosphors, respectively. Under UV light irradiation, this phosphor showed obvious long-lasting phosphorescence that can be clearly seen with naked eyes in a dark room for 18 min after the irradiation source has been removed. Thermoluminescence measurement showed that the phosphor has an appropriate energy depth of 0.43 ev.

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Jang, Taehun, MaengJun Kim et Sang Ho Sohn. « Silica Nanoparticle Coating of NaYF4:(Yb3+, Er3+) Upconversion Phosphor ». Journal of Nanomaterials 2022 (28 juillet 2022) : 1–8. http://dx.doi.org/10.1155/2022/8961362.

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To improve its light conversion efficiency, NaYF4:(Yb3+, Er3+) upconversion (UC) phosphor, which generates one visible photon by absorbing two or more near-infrared photons, was coated with SiO2 nanoparticles. The surface modification of phosphor was performed by using a modified sol–gel method as a function of the concentration of colloidal silica employed as the surface coating precursor. It was found that the PL intensities depend on the concentration of colloidal silica. When a 2.7 wt% concentration of colloidal silica was used, the NaYF4:(Yb3+, Er3+) phosphor exhibited a homogeneous coating with silica and an approximately 9% increase in the PL intensity, as compared with that of the non-coated sample of NaYF4:(Yb3+, Er3+) phosphor. This increase in the PL intensity can be explained by the suppression of the nonradiative recombination of electron–hole pairs via surface defects. The experimental results suggest that the surface modification of upconversion phosphors with a silica coating of the appropriate concentration is a simple and effective solution to improve the light conversion efficiency of upconversion phosphors used in optoelectronic devices.

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Lin, Heng, Bi Sang Chen, Yuan Zhi Chen, Guo Liang Chen, Hua Lin, Zi Shan Zheng, Zhong Hui Chen, Hong Xu Guo, Lin Feng Huang et Zhi Chen. « Encapsulation of Polyethylene for Strontium Aluminate Phosphors to Enhance its Water Resistance ». Advanced Materials Research 393-395 (novembre 2011) : 84–87. http://dx.doi.org/10.4028/www.scientific.net/amr.393-395.84.

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Phosphors of SrAl2O4:Eu2+, Dy3+ were encapsulated with polyethylene plastic film by a physical technology. Water resistance measurements, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric (TG) analysis, and photoluminescence (PL) spectrophotometry were used to characterize the phosphors Results showed that the encapsulated layer was a thin film with an encapsulation amount of 4.0 wt%, and encapsulation can effectively improve the water-resistance for the phosphor without any destroy of crystal structure of phosphors.

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Yen, Clive H., et Rui Cheong. « Application of Green Solvents for Rare Earth Element Recovery from Aluminate Phosphors ». Minerals 11, n^o 3 (10 mars 2021) : 287. http://dx.doi.org/10.3390/min11030287.

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Two processes applying green solvents for recovering rare earth elements (REEs) from different types of aluminate phosphors are demonstrated in this report. For magnesium aluminate-type phosphors, a pretreatment with peroxide calcination was implemented first, and then followed by a supercritical fluid extraction (SFE) process. Supercritical carbon dioxide (sc-CO2) provides an effective and green medium for extracting REEs from dry materials. With the addition of a complex agent, tri-n-butyl phosphate-nitric acid complex, highly efficient and selective extraction of REEs using supercritical carbon dioxide can be achieved. The highest extraction efficiency was 92% for europium from the europium doped barium magnesium aluminate phosphor (BAM), whereas the highest extraction selectivity was more than 99% for the REEs combined from the trichromatic phosphor. On the other hand, for strontium aluminate type phosphors, a direct acid leaching process is suggested. It was found out that acetic acid, which is considerably green, could have high recovery rate for dysprosium (>99%) and europium (~83%) from this strontium aluminate phosphor materials. Nevertheless, both green processes showed promising results and could have high potential for industrial applications.

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Tian, Zifeng, Hongbin Liang, Lan Li, Qiang Su, Guobin Zhang et Yibing Fu. « Vacuum ultraviolet-visible spectroscopic properties of green phosphor NaGd0.3Y0.5Tb0.2FPO4 for application in plasma display panels ». Journal of Materials Research 23, n^o 6 (juin 2008) : 1537–42. http://dx.doi.org/10.1557/jmr.2008.0203.

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In this article, we present the vacuum ultraviolet-visible spectroscopic properties of NaRFPO4:Tb3+ (R = Gd and Y). Because the samples show intensive absorption near 172 nm and bright emission, the composition of the phosphors has been further optimized and an ideal phosphor NaGd0.3Y0.5Tb0.2FPO4 is obtained. This phosphor exhibits favorable characteristics such as a lower preparation temperature, an intensive emission under 172-nm excitation, a shorter decay time (τ1/10 = 8.7 ms) in comparison with the commercial green plasma display panel (PDP) phosphor Zn2SiO4:Mn2+ (τ1/10 = 10.8 ms), a good thermal stability for luminescence performance, and a uniform particle size around 2.3 μm. Hence, the phosphor NaGd0.3Y0.5Tb0.2FPO4 can be considered a promising green phosphor for use in PDPs.

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Huang, Chun Ying, et Man Hua Wan. « Spectral Analysis of Ca_2-XBO₃Cl :xDy³⁺ Phosphors ». Materials Science Forum 663-665 (novembre 2010) : 54–57. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.54.

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PL spectra of Ca2-xBO3Cl:xDy3+ phosphors excited by 390 nm n-UV light. The intensity of both blue and yellow emissions starts to increases with the growing contents of Dy3+ ions, the strongest intensity of Dy3+ emission courses in the Ca1.95BO3Cl:0.05Dy3+ phosphor, subsequently it decreases with further adding Dy3+ ions due to concentration quenching. it can be concluded that the environment of Dy3+ ions may be less influenced due to the clustering of Dy3+ ions in the investigated phosphors after concentration quenching.

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Mancuso, James F., William B. Maxwell, Russell E. Camp et Mark H. Ellisman. « Designing high-resolution slow scan CCD-based TEM camera systems ». Proceedings, annual meeting, Electron Microscopy Society of America 50, n^o 2 (août 1992) : 946–47. http://dx.doi.org/10.1017/s042482010012936x.

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The imaging requirements for 1000 line CCD camera systems include resolution, sensitivity, and field of view. In electronic camera systems these characteristics are determined primarily by the performance of the electro-optic interface. This component converts the electron image into a light image which is ultimately received by a camera sensor.Light production in the interface occurs when high energy electrons strike a phosphor or scintillator. Resolution is limited by electron scattering and absorption. For a constant resolution, more energy deposition occurs in denser phosphors (Figure 1). In this respect, high density x-ray phosphors such as Gd2O2S are better than ZnS based cathode ray tube phosphors. Scintillating fiber optics can be used instead of a discrete phosphor layer. The resolution of scintillating fiber optics that are used in x-ray imaging exceed 20 1p/mm and can be made very large. An example of a digital TEM image using a scintillating fiber optic plate is shown in Figure 2.

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Qu, Mingyang, Xiyan Zhang, Xiaoyun Mi, Quansheng Liu et Shaoqiu Xu. « Novel red-emitting Lu3Te2Li3O12 : Eu3+ phosphor with high color purity for n-UV WLEDs ». E3S Web of Conferences 185 (2020) : 04044. http://dx.doi.org/10.1051/e3sconf/202018504044.

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In this work, a series of red emitting Lu3Te2Li3O12: Eu3+ phosphors were synthesized for the first time by high temperature solid state reaction. The structure was characterized by X-ray diffraction. The excitation spectra, emission spectra and CIE chromaticity coordinate were studied. The phosphors show strong red emission at 611 nm due to the 5D0-7F2 transition of Eu3+ ions. The optimal doping concentration of Eu3+ in LTL host is x = 0.5 due to the concentration quenching mechanism of dipole-dipole interaction. The CIE chromaticity coordinates of the LTL: 0.5Eu3++ phosphor is (0.644,0.355), and the purity of the color is up to 93.61%. The phosphor can be considered as a potential red-emitting candidate for near UV WLEDs.

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Zhang, Dandan, Huaxing Xiao, Wei Jiang, Xia Cao, Lu Huang, Gang Liu, Manyu Ye et Zhiwei Zhang. « Enhancement of the red emission in Ba3(PO4)2:Eu3+ by addition of charge compensator Na+ ». Modern Physics Letters B 32, n^o 34n36 (30 décembre 2018) : 1840063. http://dx.doi.org/10.1142/s0217984918400638.

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Ba[Formula: see text](PO4)2:0.04Eu[Formula: see text] (S1) and Ba[Formula: see text]Na[Formula: see text](PO4)2:0.04Eu[Formula: see text] (S2) were prepared by solid state reaction. The phases and luminescent properties of the obtained phosphors were characterized. The results demonstrate that the phosphors particles emit an intensive red light under excitation at 395 nm. Both phosphors can be efficiently excited by ultraviolet and blue light, and the emission spectra mainly consist of two emission peaks at 591 nm and 611 nm. The crystallographic sites of Eu[Formula: see text] ions in Ba3(PO4)2 host were discussed on the base of emission spectra and its host crystal structure. By introducing the charge compensator Na[Formula: see text] into the S1 phosphor, its emission intensity was enhanced, indicating that S2 could serve as a promising red-emitting phosphor for UV LED applications.

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Tu, Huan, Guoying Zhao, Jingshan Hou, Yufeng Liu, Yan Zhou, Ganghua Zhang, Hong-Tao Sun, Ji-Guang Li et Yongzheng Fang. « A garnet-structured (Y, Ca)₃(Al, Mg)₂(Al, Si)₃O₁₂:Ce³⁺ phosphor-in-glass engineering for use in high color rendering white LEDs ». AIP Advances 12, n^o 5 (1 mai 2022) : 055113. http://dx.doi.org/10.1063/5.0084578.

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White light emitting diodes (LEDs) suffer from two most common drawbacks: the deficiency of the red component and the poor thermal stability of silicone. Ce3+-doped garnet phosphors with tailor-made luminescence properties can be achieved by variations in {A}, {B}, and {C} cation sites. Herein, a simultaneous ion co-substitution design strategy has been adopted to synthesize a series of (Y, Ca)3(Al, Mg)2(Al, Si)3O12 garnet phosphors and corresponding phosphor-in-glass (PiG) films. The co-substitution is finely restricted to the assigned sites. The emission peak is shifted from 529 to 565 nm, which is beneficial to obtain low color temperatures and high color rendering using a single phosphor for white LEDs. By employing the as-synthesized phosphor, the corresponding PiG films were fabricated by the low temperature co-sintering technology using the SiO2–B2O3–ZnO–Na2O glass system characterized with excellent thermal stability and moisture resistance. The morphological and elemental analyses demonstrated that the as-made phosphor powders were uniformly distributed in the glass host without any interfacial reactions. Finally, modular white LEDs with a high color rendering (Ra = 82.7) is achieved through the as-synthesized PiG film on an InGaN blue chip. This study may open up a facile approach to obtain high quality luminescence based on the mono-luminescence center, avoiding excitation energy wastage and low quantum efficiency aroused by multi-luminescence centers or color compensation phosphors in glass.

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Luo, Li Jun, Yi Wen Zhu et Ping Chen. « Luminescent Properties of Eu²⁺-Activated SrAl₂Si₂O₈as an Potential Blue Phosphor for near UV LED Chips ». Advanced Materials Research 750-752 (août 2013) : 956–60. http://dx.doi.org/10.4028/www.scientific.net/amr.750-752.956.

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The phosphors SrAl2Si2O8 doped with different Eu2+ concentration were prepared by solid-state reaction technique, and their photoluminescent properties at different temperature were investigated. With the increase of Eu2+ content, two emission bands can be observed and this can be interpreted as Eu2+ ions occupying two types of sites in the crystal lattice. And their lifetime is decreasing, this result can be due to energy transfer among Eu2+ ions nonradiately at higher concentration of Eu2+ ions in the host lattices. The phosphor SrAl2Si2O8:0.40Eu shares intense blue emitting with broad excitation in the near-UV range. This phosphor may be an excellent blue phosphor for near ultraviolet InGaN-based white diodes.

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Zhang, Yun Jie, Jie Zhao, Da Jian Wang et Jian Ma. « Effect of NH4Cl Flux on Structural and Luminescent Properties of CaS : Eu²⁺ Phosphors ». Advanced Materials Research 989-994 (juillet 2014) : 755–58. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.755.

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CaS:Eu2+phosphors were prepared by two steps method at a relatively low temperature (1050°C) using NH4Cl as a flux. The influences of NH4Cl flux concentrations on the crystal structure, morphology and photoluminescent properties of CaS:Eu2+phosphors were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL), respectively. XRD analysis shows that when the raw materials added with the NH4Cl flux, the crystal structure was not changed .The SEM images indicate that increase of the NH4Cl flux enlarged the grain size of the phosphor particles. The luminescence intensity of CaS:Eu2+was enhanced with adding NH4Cl flux and up to the maximum emission intensity when the addition of NH4Cl flux is 1wt%.

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Cheng, Dan, et Zhao Hai Yang. « Preparation and Characterization of Blue-Emitting (SrCaBa)₃(PO₄)₂•SrCl₂:Eu²⁺Phosphors ». Advanced Materials Research 750-752 (août 2013) : 890–93. http://dx.doi.org/10.4028/www.scientific.net/amr.750-752.890.

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For the demand of high color rendering W-LED, we chose (SrCaBa)3(PO4)2SrCl2:Eu2+blue-emitting phosphor powder as the object of our study, and use high-temperature solid-state reaction method to prepare the phosphor powders in a weak reducing atmosphere. A detailed investigation on the reaction parameters, including kinds and relative ratio of raw materials, sintering temperature and Eu2+activator concentration was conducted in terms of luminescent properties of phosphors powder. Research findings show that optimal reaction parameters are: sintering temperature is 1200°C, Eu2+doping level is 0.15mol. By these parameters, the (SrCaBa)3(PO4)2SrCl2:Eu2+phosphor powder show bright blue emission around 450nm and can be efficiently excited by violet and ultraviolet light (200nm-440nm). Further we employed the energy transfer between Tb3+and Eu2+and prepared a series of phosphors using (SrCaBa)3(PO4)2SrCl2as host material.Research findings show that emission color can be adjusted from blue to blue green by the ratio of Tb3+to Eu2+, with line-like Tb3+green emission overlapped on band-like Eu2+blue emission.

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Cao, Renping, Hongdong Xue, Xiaoguang Yu, Fen Xiao, Donglan Wu et Fenxiang Zhang. « Luminescence Properties and Synthesis of SrMgAl10O17:Mn4+ Red Phosphor for White Light-Emitting Diodes ». Journal of Nanoscience and Nanotechnology 16, n^o 4 (1 avril 2016) : 3489–93. http://dx.doi.org/10.1166/jnn.2016.11793.

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A series of Mn4+ doped SrMgAl10O17 phosphors are synthesized by a conventional solid-state reaction method in air, and their crystal structure, morphology, and fluorescence properties are investigated. The luminescence properties show clearly that SrMgAl10O17:Mn4+ phosphor can be excited by UV (200–380 nm), near UV (380–420 nm), and blue (420–480 nm) bands of LEDs chip, and emits red light in the range of 600 nm to 750 nm with satisfying CIE chromaticity coordinates (0.7207, 0.2793). The optimal doping concentration of Mn4+ ion is ∼1 mol%, and its lifetime is ∼1.15 ms. The possible luminous mechanism of Mn4+ ion is discussed by Tanabe-Sugano diagram. These experiment results indicate that Mn4+ doped SrMgAl10O17 phosphors can be a potential application as a red-emitting phosphor candidate in white LEDs.

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Shi, Tingxing, Feng Chen, Xiyu Zhao, Jiahua Zhang, Xiao-Jun Wang et Feng Liu. « Charging storage phosphors using a white flashlight via the upconversion approach ». Applied Physics Letters 121, n^o 19 (7 novembre 2022) : 191902. http://dx.doi.org/10.1063/5.0122858.

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As an emerging approach to charge storage phosphors, upconversion charging (UCC) is attracting increased attention owing to its fundamental and practical perspectives. Despite the potential, further development of the UCC technology is restricted by the limited types of excitation light sources. Here, we use a white flashlight as excitation to investigate the UCC performance of storage phosphors. We demonstrate, as an example, that a Y3Al2Ga3O12:Pr3+ phosphor exhibits long-lasting emissions in the ultraviolet and visible regions after intense illumination from the flashlight. Thermoluminescence investigations reveal that both excited-state absorption and energy-transfer upconversion are involved in the UCC process. Based on the luminescence performance of the white-light charged phosphor, a conceptual thermometry approach is introduced, which can remotely sense the local temperature by monitoring the afterglow intensity ratio. Considering the wide use of flashlight, such a white-light excitability and the associated glow emission may potentially revolutionize the way to utilize storage phosphors.

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Sun, Wen-Shing, et Chuen-Lin Tien. « Optical Modeling Analysis of Red, Green, and Yellow Phosphors with a Blue LED ». Advances in Condensed Matter Physics 2018 (1 août 2018) : 1–10. http://dx.doi.org/10.1155/2018/5716259.

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The luminous properties of red, green, and yellow phosphors with a blue LED are evaluated and a corresponding optical model is constructed using the optical simulation software LightTools®. According to the phosphor particle model, the desired chromaticity coordinate of the multicomponent light which is excited by a blue LED can be achieved by modifying the weight concentration of the phosphors. A comparison of the four types of LED package modules tested shows that the yellow phosphor encapsulated with a semispherical module takes up a lesser percentage of the total weight percentage of a constructed white light with a correlated color temperature of around 4000 K. The simulation and experimental results provide a cross-reference for better packaging and encapsulating designs for lumen improvement.

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Lin, Chih-Hao, Che-Hsuan Huang, Yung-Min Pai, Chung-Fu Lee, Chien-Chung Lin, Chia-Wei Sun, Cheng-Huan Chen, Chin-Wei Sher et Hao-Chung Kuo. « Novel Method for Estimating Phosphor Conversion Efficiency of Light-Emitting Diodes ». Crystals 8, n^o 12 (27 novembre 2018) : 442. http://dx.doi.org/10.3390/cryst8120442.

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This study presents a novel method for estimating the phosphor conversion efficiency of white light-emitting diodes (WLEDs) with different ratios of phosphors. Numerous attempts have been made for predicting the phosphor conversion efficiency of WLEDs using Monte Carlo ray tracing and the Mie scattering theory. However, because efficiency depends on the phosphor concentration, obtaining a tight match between this model and the experimental results remains a major challenge. An accurate prediction depends on various parameters, including particle size, morphology, and packaging process criteria. Therefore, we developed an efficient model that can successfully correlate the total absorption ratio to the phosphor concentration using a simple equation for estimating the spectra and lumen output. The novel and efficient method proposed here can accelerate WLED development by reducing costs and saving fabrication time.

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Jargus, Vitasek, Nedoma, Vasinek et Martinek. « Effect of Selected Luminescent Layers on CCT, CRI, and Response Times ». Materials 12, n^o 13 (28 juin 2019) : 2095. http://dx.doi.org/10.3390/ma12132095.

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Phosphors have been used as wavelength converters in illumination for many years. When it is excited with blue light, the frequently used yttrium aluminium garnet doped with cerium (YAG:Ce) phosphor converts a part of blue light to a wideband yellow light, resulting in the generated light having a white color. By combining an appropriate concentration of the YAG:Ce phosphor and blue excitant light, white light of a desired correlated color temperature (CCT) can be obtained. However, this type of illumination has a lower color rendering index value (CRI). In an attempt to improve the CRI value, we mixed the YAG:Ce phosphor with europium-doped calcium sulfide phosphor (CaS:Eu), which resulted in a considerably increased CRI value. This article examines an experiment with luminescent layers consisting of a mixture of selected phosphors and polydimethylsiloxane (PDMS). Different thicknesses in these layers were achieved by changing the speed of rotation during their accumulation onto laboratory glass using the method of spin coating. The spectral characteristics of these luminescent layers as they were excited with blue light emitting diode (LED) and laser diode (LD) were then determined. A suitable combination of the YAG:Ce phosphor with a phosphor containing europium, as it was excited with a blue LED, yielded a source of white light with a CRI value of greater than 85. The response time in the tested luminescent layers to a rectangular excitant impulse (generated by a signal generator and transmitted by LD) was also measured in order to examine their potential use in visible light communications (VLC).

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Noel, B. W., H. M. Borella, W. Lewis, W. D. Turley, D. L. Beshears, G. J. Capps, M. R. Cates, J. D. Muhs et K. W. Tobin. « Evaluating Thermographic Phosphors in an Operating Turbine Engine ». Journal of Engineering for Gas Turbines and Power 113, n^o 2 (1 avril 1991) : 242–45. http://dx.doi.org/10.1115/1.2906554.

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The results of a field test in a commercial turbine engine showed that we can remotely measure the temperature of engine components in operating engines using thermographic phosphors. The remote-measurement method exploits the temperature dependence of the characteristic decay time of the laser-induced fluorescence of thermographic phosphors. This paper summarizes recent work leading up to and including a successful test of the thermographic-phosphor method in an operating turbine engine.

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Wang, Qun Si, Jun Feng Ma, Tian Qing Cui, Dong Bin Tang et Qi Zhou. « Preparation of M2SiO4 ;:Tb3+, Mn2+, Nd3+ ; White-Emitting Phosphors (M = Mg2+, Ca2+, Sr2+, and Ba2+) and the Influence of M2+ ; Cations on their Luminescent Performance ». Key Engineering Materials 904 (22 novembre 2021) : 329–33. http://dx.doi.org/10.4028/www.scientific.net/kem.904.329.

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M2SiO4: Tb3+, Mn2+, Nd3+ (M = Mg2+, Ca2+, Sr2+, and Ba2+) phosphors suitable for near-ultraviolet-violet radiation excitation were successfully prepared at 1400 °C in N2 atmosphere by a high-temperature solid-state reaction, and their phase compositions and luminescent performance were also studied by X-ray diffraction (XRD), photoluminescence spectra. Results show that their emission intensity increases in the order of Ca2SiO4 > Mg2SiO4 > Sr2SiO4 > Ba2SiO4 matrix phosphor. Ca1.94SiO4: 0.02Tb3 +, 0.02Mn2+, 0.02Nd2+ phosphor exhibits the best luminescence performance.

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Yan, Xiao Song, Wan Wan Li et Kang Sun. « White-Light-Emitting Phosphate Phosphors of SrZn₂(PO₄)₂ : Eu²⁺, Mn²⁺ Synthesized through Combustion Process ». Materials Science Forum 688 (juin 2011) : 344–48. http://dx.doi.org/10.4028/www.scientific.net/msf.688.344.

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The SrZn2(PO4)2: Eu2+, Mn2+ phosphors were synthesized through combustion process with varying mixture ratio of Eu2+, Mn2+. The SrZn2(PO4)2: Eu2+, Mn2+ phosphor presents three emission bands under 365nm radiation: the blue emission band of 416 nm from Eu2+ occupying the Sr2+ site, the green emission band of 538 nm and the red emission band of 630 nm from Mn2+ occupying two different Zn2+ sites. Compared with the SrZn2(PO4)2: Eu2+, Mn2+ phosphor prepared through solid state reaction, the luminous intensity of the phosphor is greatly improved through the combustion reaction. White emission light with a high color rending index of 84.7 can be obtained from the phosphor of SrZn2(PO4)2: Eu2+, Mn2+, and the emission color tone of the phosphor varies from blue, white, and finally yellow by increasing the ratio of the concentrations of Eu2+ and Mn2+.

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Luo, Lijun, Fenfen Hu, Li Xiong, Xiaofan Li, Meili Zhou et Zhengliang Wang. « Luminescent Properties of Y2O3:Eu3+Nanocrystals Prepared by Molten Salt Synthesis ». Journal of Nanomaterials 2013 (2013) : 1–4. http://dx.doi.org/10.1155/2013/952623.

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A series of red phosphors Y2O3:Eu3+were prepared by the molten salt method with different surfactants. Their structures, morphologies, and the photoluminescent properties were investigated at room temperature. The particles size of Y2O3:Eu3+can be controlled by adjusting the kinds of surfactants. The phosphor Y2O3:Eu3+prepared with NP-10 [polyoxyethylene (10) nonyl phenyl ether] shows regular morphology and higher crystallinity, and its average particle size is about 200 nm. Bright red light can be observed by naked eyes from the red phosphor under 254 nm excitation.

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