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1.
Yttrium aluminum garnet (YAG) doped with Ce3+ ion is known as an excellent phosphor for light-emitting diode (LED), usually used as a powder form dispersed in organic resins. We have developed translucent glass-ceramics (GC) of YAG: Ce3+ microcrystals in 2004. The GC sheet with half millimeter thick can work efficiently to make identical emission spectra with conventional white LED when combined with a blue LED. This report reviews the development history of the GC materials and impact for all inorganic solution for solid-state lighting. 相似文献
2.
Setsuhisa Tanabe 《International Journal of Applied Glass Science》2015,6(4):305-328
Light-based technologies are strongly supported by various glass materials in general. This article focuses on glasses containing rare-earth elements, doped fibers, as well as their photonic functions such as optical amplifications in fiber telecommunication. Scientific progress and applications of rare-earth spectroscopy and technologies of doped glasses and fibers in recent 60 years have been more than dramatic. Development of various laser diodes has been strongly linked with realization of novel devices of rare-earth-doped glasses. In addition to many milestones listed in the resolution of International Year of Light, we should notice that 2015 is also the 50th anniversary of the erbium-doped glass laser, which is later transformed into the optical fiber amplifier, the enabler of today's information society. 相似文献
3.
Setsuhisa Tanabe† Teiichi Hanada† Masayuki Watanabe‡ Tetsusuke Hayashi‡ Naohiro Soga§ 《Journal of the American Ceramic Society》1995,78(11):2917-2922
Dysprosium-doped glasses were prepared in the system of gallium-based sulfide, tellurite, zirconium-baed and indium-based fluorides and their optical properties were studied. From the absorption cross sections of five f-f bands, three Judd-Ofelt parameters, ω t ( t = 2, 4, 6), of Dy3+ ion were determined. The compositional variaton of the ω2 value showed the order sulfide > tellurite > fluorozirconate > fluoroindate, whereas the ω6 value showed the opposite tendency. Compositional variaton of the fluorescence intensity ratio of the (4 F9/2 6 H13/2 )/(4 F9/2 )→6 H15/2 ) is explained by the ratio of ω2 /ω6 of doped Dy3+ . The emission probabilities A and the branching ratio β from 6 H9/2 and 6 F11/2 levels, which are the doublet initial level of the 1.3 μm luminescence, were calculated for the glasses, and it was found that both values showed a tendency similar to that of ω2 against the glass composition. In the sulfide glass, A was 2.6 × 103 S-1 and β was 93%, both the highest in all of the glasses investigated. By 1.06 μm pumping of a Nd: YAG laser, the sulfide glass showed strong 1.3 μm emission and the lifetime was 25 μs, resulting in a quantum efficiency of 7%. This value is higher than that of the Pr3+ :1 G4 level in ZBLAN glass with β= 60%. 相似文献
4.
Enhanced Light Storage of SrAl2O4 Glass‐Ceramics Controlled by Selective Europium Reduction
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Takayuki Nakanishi Kazune Watanabe Jumpei Ueda Koji Fushimi Setsuhisa Tanabe Yasuchika Hasegawa 《Journal of the American Ceramic Society》2015,98(2):423-429
A luminescent Eu, Dy: SrAl2O4 glass‐ceramics with high transparency in the visible region was successfully synthesized using the frozen sorbet technique with the control of O2 partial pressure () for the oxidation of Eu2+ ions. The glass‐ceramics include Eu2+, Eu3+, and Dy3+ ions, and thus exhibits three characteristic types of emission bands, 4f–5d at around 520 nm (Eu2+ ions), 4f–4f at 610 nm (Eu3+ ions), and 480 nm (Dy3+ ions). The Eu, Dy: SrAl2O4 glass‐ceramics provide remarkable long‐persistent luminescence under dark condition. The glass‐ceramics also exhibits color‐changing luminescence in the visible region based on their remarkable light storage properties. The luminescent Eu, Dy: SrAl2O4 glass‐ceramics using the frozen sorbet technique with control of are promising materials for application in novel photonic and light storage materials. 相似文献
5.
Yixi Zhuang Setsuhisa Tanabe Jianrong Qiu 《Journal of the American Ceramic Society》2014,97(11):3519-3523
Four Cr4+‐activated transparent glass‐ceramics containing different species of silicate nano‐crystals (Zn2SiO4, Mg2SiO4, Li2ZnSiO4, and Li2MgSiO4) were successfully prepared. Absorption spectra, photoluminescence spectra, lifetime decay curves, and quantum yield of these transparent glass‐ceramics were measured. According to the crystal field strength of Cr4+‐incorporated tetrahedral sites, the broadband near‐infrared (NIR) luminescence of Cr4+ can be tailored from 1130 to 1350 nm and the lifetime of Cr4+ luminescence can be prolonged from 6 to 100 μs. Quantum yield in the transparent glass‐ceramics containing Li2ZnSiO4 nano‐crystals reached at 17%, which is the highest value of NIR luminescence in transition‐metal‐activated glass materials. 相似文献
6.
Y. MORIWAKI T. TATSUKI A. TOKIWA-YAMAMOTO T. TAMURA S. ADACHI K. TANABE 《Journal of Materials Science Letters》1997,16(2):115-116
Abstracts are not published in this journal 相似文献
7.
Garnet structure (A3B2C3O12) with three different cation sites is a very flexible host material widely used for w‐LEDs, solid‐state lasers, scintillators, and so on. In this work, we have successfully developed six different Cr3+‐doped garnets: Y3Ga4.99Cr0.01O12 (YGG:Cr), Gd3Ga4.99Cr0.01O12 (GGG:Cr), Lu3Ga4.99Cr0.01O12 (LuGG:Cr), Y3Sc1.99Cr0.01Ga3O12 (YSGG:Cr), Gd3Sc1.99Cr0.01Ga3O12 (GSGG:Cr), and Lu3Sc1.99Cr0.01Ga3O12 (LuSGG:Cr), which exhibit persistent luminescence (PersL) due to Cr3+ emission matching well with both the response curve of the Si detector and the wavelength region of the first biological window (NIR‐I, 650‐950 nm). The main emission band of Cr3+ in these garnets can be easily tunable from the sharp R‐line emission due to the 2E (2G)→4A2 (4F) transition in the strong crystal field to the broad band emission due to the 4T2 (4F)→4A2 (4F) transition in the weak one when Lu3+ in the A site and Ga3+ in the B site are, respectively, replaced by larger cations, Y3+/Gd3+ and Sc3+. Furthermore, based on the knowledge of 4f energy levels of 15 lanthanide ions in the host‐referred binding energy (HRBE) diagram, we took the GSGG host as a typical example to discuss the feasibility of four trivalent lanthanides (Sm3+, Eu3+, Tm3+, Yb3+) as potential sensitizers for enhancing Cr3+ PersL. 相似文献
8.
K. KIDA H. TANABE H. OKANO 《Fatigue & Fracture of Engineering Materials & Structures》2009,32(3):180-188
Fatigue failure of steel occurs when small cracks form in a component and then continue to grow to a size large enough to cause failure. In order to understand the strength of steel components, it is important to find the cracks, which eventually grow to cause failures. However, at present, it is not easy to distinguish, in the early stages of growth, the cracks that will grow fast and cause failure.
We hypothesized that it may be possible to distinguish them by comparing changes in the magnetic flux density around the tips of those cracks that grew to failure. In order to measure these changes in magnetic flux density, we developed a scanning Hall probe microscope and observed the fatigue cracks growing from artificial slits in soft bearing steels. Note that we did not magnetize the specimens artificially but succeeded to measure the changes in magnetic flux density during the fatigue tests. We also compared the changes in magnetic flux density around crack tips, which grew under different loads, and found that there is a strong correlation between the magnetic flux density, crack growth and stress intensity factors. In order to understand this, we looked into the relation between stress field, residual strain and magnetic flux density, and concluded that the changes in magnetic flux density are caused not only by the residual strain occurring around the crack tips but also by the increase in the elastic stress. 相似文献
We hypothesized that it may be possible to distinguish them by comparing changes in the magnetic flux density around the tips of those cracks that grew to failure. In order to measure these changes in magnetic flux density, we developed a scanning Hall probe microscope and observed the fatigue cracks growing from artificial slits in soft bearing steels. Note that we did not magnetize the specimens artificially but succeeded to measure the changes in magnetic flux density during the fatigue tests. We also compared the changes in magnetic flux density around crack tips, which grew under different loads, and found that there is a strong correlation between the magnetic flux density, crack growth and stress intensity factors. In order to understand this, we looked into the relation between stress field, residual strain and magnetic flux density, and concluded that the changes in magnetic flux density are caused not only by the residual strain occurring around the crack tips but also by the increase in the elastic stress. 相似文献
9.
Haipeng Ji Jian Xu Kazuki Asami Jumpei Ueda Mikhail G. Brik Setsuhisa Tanabe 《Journal of the American Ceramic Society》2019,102(3):1316-1328
Sr2GdAlO5:Ce and Sr3AlO4F:Ce are isostructural phosphors in which the Ce3+ 4f-5d1 transition can be efficiently excited by a photon with energy lower than 3.1 eV. Herein, we analyze the crystal chemistry of the Ce3+ local coordination, compare the thermal quenching behavior and construct the electronic structure of Ce3+ in them. The Rietveld refinement on two occupancy models suggests that Gd3+ only occupies the 8h site in Sr2GdAlO5; this provides a hint on the preferred occupancy of dopant Ce3+ in this site. The large crystal filed splitting of Ce8h is mainly due to the fact that the 8h site is bonded to two oxygen with relatively short dSr/Gd-O and forms a quasi-square antiprism which experiences a large distortion. The Ce3+ 5d-4f luminescence in Sr3AlO4F is much more stable against thermal quenching than that in Sr2GdAlO5, as evidenced by the temperature-dependent luminescence intensity and luminescence decay studies. The energy of the O2−-Eu3+/2+ and O2−-Ce4+/3+ charge transfer as well as bandgap were estimated and the electronic structure of Ce3+ were constructed. A larger energy barrier ΔEdC between the Ce3+ 5d1 level and the conduction band bottom in Sr3AlO4F is seen from the Vacuum Referred Binding Energy (VRBE) diagrams which explains the higher thermal quenching temperature by thermal ionization model. 相似文献
10.
Teiichi Hanada Takuya Shinoda Setsuhisa Tanabe Naohiro Soga 《Journal of the American Ceramic Society》1995,78(5):1383-1386
Amorphous films in the SiO2 -Y2 O3 system were prepared by the rf-sputtering method. Transparent amorphous films were obtained in the region between 0 and 66 mol% Y2 O3 content, only in an oxygen atmosphere. The densities and elastic constants of the films were determined. As the amount of Y2 O3 addition increased, density and elastic constants increased up to about 45 mol% Y2 O3 , beyond which it held constant. From the relationship between the bulk modulus and the mean atomic volume, a structural change in the present films seems to occur at about 45 mol% Y2 O3 content. 相似文献