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1.
With regard to phosphor thermometry, seven luminescent ceramic materials were synthesised and characterised, namely CaMoO4:Eu3+, CaTiO3:Pr3+, LaPO4:Eu3+, LaVO4:Eu3+, LiAl5O8:Fe3+, TiMg2O4:Mn4+ and ZnGa2O4:Mn2+. In this context, emission spectra and temperature lifetime characteristics are presented. Thus, a survey of phosphors novel for thermography is given in order to encourage further studies and more detailed characterisations of the respective materials. 相似文献
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Ying Guo Meng Sun Wanmei Guo Fuqiang Ren Donghua Chen 《Optics & Laser Technology》2010,42(8):1328-1331
A novel red-emission phosphor of Eu3+-doped tungstate was prepared at 950 °C by a modified solid-state reaction. Photoluminescence (PL) results showed that the phosphor can be efficiently excited by irradiation at wavelengths in the near-UV and blue regions of the spectrum. The material has potential application as the fluorescent material for ultraviolet light-emitting diodes (UV-LEDs). The crystallization and particle sizes of the phosphor have been investigated by using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). 相似文献
3.
The new trivalent dysprosium activated X6AlP5O20 (where X=Sr, Ba, Ca and Mg) phosphors were prepared by the combustion method. The prepared phosphors are characterized by XRD, photoluminescence and SEM techniques. Excited by 350 nm near-ultraviolet (NUV) light, the phosphors show an efficient blue and yellow band emissions, which originates from the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions of Dy3+ ion, respectively. The excitation spectra of the phosphors are broadband extending from 340 to 400 nm, which are characteristics of NUV excited LED. The effect of the Dy3+ concentration on the luminescence properties of X6AlP5O20:Dy3+ (where X=Sr, Ba, Ca and Mg) phosphors is studied. Ca6AlP5O20 phosphors show strong PL emission intensity around 25 times more as compared to Ba6AlP5O20, Sr6AlP5O20 and Mg6AlP5O20 phosphors. The investigated prepared phosphors are suitable for a NUV excited LED. 相似文献
4.
《Current Applied Physics》2010,10(4):1087-1091
Eu2+ and Mn2+ co-doped calcium aluminate silicate chloride phosphors with the chemical composition of Ca3Al2Si2O8Cl4:Eu2+, Mn2+ have been prepared by a solid-state method, and their luminescence properties have been investigated by tuning the En2+/Mn2+ ions concentration. The phase formation and microstructure of Ca3Al2Si2O8Cl4:Eu2+, Mn2+ phosphors have been illuminated by XRD and SEM analysis. Photoluminescence (PL) spectrum reveals that Ca3Al2Si2O8Cl4:Eu2+ exhibits a strong blue emission band centered at 431 nm, while Ca3Al2Si2O8Cl4:Eu2+, Mn2+ can emit bluish-white light by adjusting the Mn2+ content appropriately. The energy transfer mechanism involving Eu2+–Mn2+ have also been investigated. 相似文献
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Shinnosuke Kamei Yoshiyuki Kojima Nobuyuki Nishimiya 《Journal of luminescence》2010,130(11):2247-2250
This study reports the synthesis of novel red-emitting Eu3+-activated amorphous alkaline earth silicate phosphors with high emission intensities. Eu3+-activated barium (strontium) silicate hydrate phosphors were synthesized using a liquid phase reaction and then heated at 850 °C for 0.5 h to form amorphous barium (strontium) silicate phosphors. These amorphous phosphors emitted in the red region following near-UV (395 nm) irradiation. The internal quantum efficiencies of the Eu3+-activated amorphous barium silicate phosphor and strontium silicate phosphor were 56% and 60%, respectively, even though these phosphors were in the amorphous state. 相似文献
6.
A novel strategy to improve the sensitivity of aerosol phosphor thermometry using co-doped phosphors
《Proceedings of the Combustion Institute》2019,37(2):1393-1400
A novel strategy is presented to improve the temperature sensitivity and potentially extend the temperature range of aerosol phosphor thermometry (APT) by co-doping host materials with two rare-earth ions. The ratio of the emission bands from each ion are measured and calibrated versus temperature to utilize the high sensitivity of thermographic phosphor absolute signal levels. The potential of the technique is illustrated using trivalent cerium (Ce3+) and praseodymium (Pr3+) co-doped into yttrium aluminum garnet (Ce,Pr:YAG). The measured fractional sensitivity of this phosphor from 300–450 K was 0.004–0.006 K−1, a factor of 1.5–2 better than previously observed for Eu:BAM. Additionally, the single-shot precision (1σ) was between 9 and 25 K over the range of temperatures measured, illustrating the utility of this co-doping strategy. The level of temperature sensitivity and single-shot precision observed here should be achievable over different temperature ranges by doping Ce3+ and Pr3+ into different hosts. This new strategy should provide a pathway to ultimately extend the high-temperature single-shot measurement limit for APT to temperatures greater than 1000 K and push forward the state-of-the-art for planar temperature diagnostics in combustion applications. 相似文献
7.
Jin Young Park Hong Chae Jung G. Seeta Rama Raju Jung Hyun Jeong Byung Kee Moon Jung Hwan Kim Young Kuk Lee 《Current Applied Physics》2013,13(3):441-447
The color rendering index (CRI) and structural stability of cerium doped yttrium aluminum garnet (YAG:Ce) based phosphors have been enhanced by replacing Y3+ ions by larger radius ions (Tb3+, Gd3+, Eu3+, and Sm3+) at the dodecahedral site and replacing Al3+ ions by larger ones (Ga3+, Y3+, Tb3+, Gd3+, and Sm3+) at the octahedral site. These aluminum garnet crystalline powders were prepared by solvothermal reaction method at 300 °C for 48 h. The lattice constant values of synthetic aluminum garnet crystalline powders are larger than that of YAG and the emission wavelength of Ce3+ ion of these samples is longer than that of YAG:Ce. FESEM and TEM studies revealed that the Ln3Ga2Al3O12 and Ln3Al2Al3O12 crystalline powders have 3-dimensional star-like morphology with submicron size and good crystallinity, while, Ln3(LnAl)Al3O12 garnet crystalline powders were cubic crystalline phases and shaped as cubes with the round edge having an approximate diameter of about 200–400 nm. All the prepared powders were grown along (100) direction and crystallized into single crystal. Also, the effects of treatment time and reaction temperature on the structure of aluminum garnet crystalline powders have been investigated. 相似文献
8.
Willi Lehmann 《Journal of luminescence》1973,6(5):455-470
Preparation conditions, emission spectra, and optical absorption spectra are given for CaO-phosphors containing 17 different activators. Spectra and performances are compared to those of corresponding CaS phosphors. CaO is less versatile as a phosphor host material than CaS and, with few exceptions, CaO-phosphors are less efficient. Technical use of the few efficient CaO-phosphors is restricted because of chemical stability problems of CaO in open air. 相似文献
9.
Ion-implanted phosphors were prepared by implanting Sb in CaS at 25 keV with concentration ranging from 0.05 to 0.2% by weight.
Samples of similar concentration were also prepared using the conventional technique. The spectral response under UV excitation
of both types of samples is compared. 相似文献
10.
The published data on photostimulated luminescence and some new results obtained by the authors with the KCl-Tl phosphor are analyzed. It is shown that for phosphors with associated donor-acceptor pairs photo stimulated luminescence appears as a consequence of an inter-impurity electronic transition. The kinetic aspects of the luminescence depend upon the Coulomb attraction between a quasi-free electron and a charged donor. The character of the radiative recombination is determined by the interaction energy between the two partners and by the trap depth. This enables us to consider various well-known phosphor models from a general point of view. It is emphasized that the coexistence of various mechanisms in the same phosphor must be taken into account to obtain a correct interpretation of the luminescence characteristics. It is also shown that, for the mechanism involving free holes, an exciton must be created before the recombination energy can be transferred to the luminescent center. 相似文献
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G. M. Ivanii 《Journal of Applied Spectroscopy》1971,15(5):1535-1536
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Understanding the structural origins of the photoelastic response in oxide glasses is important for discovering new families of zero-stress optic glasses and for developing a predictive physical model. In this Letter, we have investigated the composition dependence of the stress optic coefficient C of 32 sodium aluminosilicate glasses with different types of alkaline earth oxides (MgO, CaO, SrO, and BaO). We find that most of the composition dependence of the stress optic response can be captured by a linear regression model and that the individual contributions from the alkaline earths to C depend on the alkaline earth-oxygen bond metallicity. High bond metallicity is required to allow bonds to be distorted along both the bonding direction and perpendicular to it. These findings are valuable for understanding the photoelastic response of oxide glasses. 相似文献
15.
The temperature, magnetic field, and frequency dependences of the ac susceptibility for an aluminosilicate glass containing 14.3 at% cobalt have been measured. These results show significant differences with the dc measurements in very low fields at all temperatures above and below the spin glass freezing temperature Tf. 相似文献
16.
《Radiation measurements》2007,42(4-5):582-585
The dose response of three LiF TLDs: standard LiF:Mg,Ti (denoted MTS), high-sensitive LiF:Mg,Cu,P (MCP) and a recently developed in Kraków version of LiF:Mg,Ti with modified activator composition (MTT) and increased high-LET response was measured. The TLDs have been exposed to 60Co gamma-rays, up to dose of 10 000 Gy, i.e. beyond saturation dose of the main dosimetric peaks, which corresponds to ca. 1000 Gy. The measured glow-curves were deconvolved into separate peaks with first order kinetic function (using self-developed GlowFit software). The dose response of the main peaks was found to be supralinear for MTS and sublinear for MCP detectors, as expected. The dose response of MTT was found to be even more supralinear than that of MTS. An interesting effect has been observed with regard to glow-curve shape of MCP detectors. Up to a dose of 1 kGy it remains practically unchanged, while for higher doses a strong growth of high-temperature peaks is observed. In the same dose region a decrease of the main peak of MCP with increasing dose is observed, unlike LiF:Mg,Ti detectors. 相似文献
17.
Excitation and emission spectra of KCl : Tl phosphors having higher Tl content (Tl ≈ 0.01 m.f. and above) were examined with the help of Aminco-Bowman spectrophotofluorometer. Measurements also included the luminescence study of TlCl powder and TlCl solution. It is observed that there is parallelism in the excitation and emission spectra of heavily-doped KCl : Tl phosphor, TlCl powder and aqueous TlCl-solution. It is concluded that heavily-doped KCl : Tl phosphor contains undissociated TlCl molecules which act as luminescence centres. 相似文献
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Heinz von Seggern Sabine Hesse J?rg Zimmermann Graham A. Appleby Xianguo Meng Claudia Fasel Ralf Riedel 《Radiation measurements》2010,45(3-6):478-484
We present a single step synthesis method for the photostimulable X-ray storage phosphor BaFBr:Eu2+ which results in a highly sensitive powder with a relatively small average grain size of 5.4 μm. The starting chemical reagents are BaCO3, NH4F, NH4Br and EuF3. The reaction initiated by the decomposition of the ammonium materials leads to highly volatile hydrogen halide gases which react with the BaCO3 to form BaFBr at temperatures up to 300 °C. Further heating results in the incorporation of Eu2+ and the formation of halide vacancies at temperatures in between 390 and 580 °C. The resulting photostimulated luminescence (PSL) efficiency is optimized after sintering at 800 °C. The reaction process is monitored by differential thermal analysis (DTA) and the reaction products are detected by mass-spectroscopy which confirms the proposed chemical reactions. Intermediate and final products are identified using X-ray diffraction. Photoluminescence (PL) and PSL spectra show the incorporation of Eu2+ into the lattice, as well as a PL peak at 470 nm which is not present in the PSL spectrum. This peak is shown to originate from O2? in the lattice and directly affects the PSL sensitivity. 相似文献