| Title | Formation of Deep Electron Traps by Yb Codoping Leads to Super-Long Persistent Luminescence in Ce-Doped Yttrium Aluminum Gallium Garnet Phosphors. |
|---|---|
| Authors | J. Ueda; S. Miyano; S. Tanabe |
| Journal | ACS Appl Mater Interfaces |
| DOI | 10.1021/acsami.8b02758 |
| Abstract |
The YAlGaO:Ce-Cr compound is one of the brightest persistent phosphors, but its persistent luminescence duration is not so long because of the relatively shallow Cr electron trap. To compare the vacuum referred binding energy of the electron trapping state by Cr and lanthanide ions, we selected Yb as a deeper electron trapping center. The YAlGaO:Ce-Yb phosphors show Ce:5d ? 4f green persistent luminescence after blue light excitation. The formation of Yb was confirmed by the increased intensity of absorption due to Yb:4f-5d at 585 nm during the charging process. This result indicates that the Yb ions act as electron traps by capturing an electron. From the thermoluminescence glow curves, it was found that the Yb trap makes a much deeper electron trap with a 1.01 eV depth than the Cr electron trap with a 0.81 eV depth. This deeper Yb trap provides a much slower detrapping rate of filled electron traps than the Cr-codoped persistent phosphor. In addition, by preparing transparent ceramics and optimizing Ce and Yb concentrations, the YAlGaO:Ce(0.2%)-Yb(0.1%) as-made transparent ceramic phosphor showed super-long persistent luminescence for over 138.8 h after blue light charging. |
See more Aluminum products. Aluminum (or Aluminium) (atomic symbol: Al, atomic number: 13) is a Block P, Group 13, Period 3 element with an atomic weight of 26.9815386. It is the third most abundant element in the earth's crust and the most abundant metallic element. 
Aluminum's name is derived from alumina, the mineral from which Sir Humphrey Davy attempted to refine it from in 1812. Aluminum was first predicted by Antoine Lavoisier 1787 and first isolated by Hans Christian Øersted in 1825. Aluminum is a silvery gray metal that possesses many desirable characteristics. It is light, nonmagnetic and non-sparking. It stands second among metals in the scale of malleability, and sixth in ductility. It is extensively used in many industrial applications where a strong, light, easily constructed material is needed. 
Although it has only 60% of the electrical conductivity of copper, it is used in electrical transmission lines because of its light weight. Pure aluminum is soft and lacks strength, but alloyed with small amounts of copper, magnesium, silicon, manganese, or other elements, it imparts a variety of useful properties.
See more Gallium products. Gallium (atomic symbol: Ga, atomic number: 31) is a Block P, Group 13, Period 4 element with an atomic weight of 69.723.The number of electrons in each of Gallium's shells is 2, 8, 18, 3 and its electron configuration is [Ar] 3d10 4s2 4p1. The gallium atom has a radius of 122.1 pm and a Van der Waals radius of 187 pm. 
Gallium was predicted by Dmitri Mendeleev in 1871. It was first discovered and isolated by Lecoq de Boisbaudran in 1875. In its elemental form, gallium has a silvery appearance. 
Gallium is one of three elements that occur naturally as a liquid at room temperature, the other two being mercury and cesium. Gallium does not exist as a free element in nature and is sourced commercially from bauxite and sphalerite. Currently, gallium is used in semiconductor devices for microelectronics and optics. The element name originates from the Latin word 'Gallia' referring to Gaul, the old name of France.
See more Ytterbium products. Ytterbium (atomic symbol: Yb, atomic number: 70) is a Block F, Group 3, Period 6 element with an atomic weight of 173.054. 
The number of electrons in each of Ytterbium's shells is [2, 8, 18, 32, 8, 2] and its electron configuration is [Xe]4f14 6s2. The Ytterbium atom has a radius of 176 pm and a Van der Waals radius of 242 pm. Ytterbium was discovered by Jean Charles Galissard de Marignac in 1878 and first isolated by Georges Urbain in 1907.
In its elemental form, ytterbium has a silvery-white color. Ytterbium is found in monazite sand as well as the ores euxenite and xenotime. Ytterbium is named after Ytterby, a village in Sweden. Ytterbium can be used as a source for gamma rays, for the doping of stainless steel, or other active metals. Its electrical resistivity rises under stress, making it very useful for stress gauges that measure the deformation of the ground in the even of an earthquake.
See more Yttrium products. Yttrium (atomic symbol: Y, atomic number: 39) is a Block D, Group 3, Period 5 element with an atomic weight of 88.90585. 
The number of electrons in each of yttrium's shells is [2, 8, 18, 9, 2] and its electron configuration is [Kr] 4d1 5s2. The yttrium atom has a radius of 180 pm and a Van der Waals radius of 219 pm. Yttrium was discovered by Johann Gadolin in 1794 and first isolated by Carl Gustav Mosander in 1840. In its elemental form, Yttrium has a silvery white metallic appearance. Yttrium has the highest thermodynamic affinity for oxygen of any element. 
Yttrium is not found in nature as a free element and is almost always found combined with the lanthanides in rare earth minerals. While not part of the rare earth series, it resembles the heavy rare earths which are sometimes referred to as the "yttrics" for this reason. Another unique characteristic derives from its ability to form crystals with useful properties. The name yttrium originated from a Swedish village near Vaxholm called Yttbery where it was discovered.