Blue emission of Eu2+-doped translucent alumina

Abstract

a b s t r a c tInorganic scintillators are very important in medical and industrial measuring systems in the detection and measurement of ionizing radiation. In addition to Ce 3 þ , a widely used dopant ion in oxide scintillators, divalent Europium (Eu 2 þ ) has shown promise as a high-luminescence, fast-response luminescence center useful in the detection of ionizing radiation. In this research, aluminum oxide (Al 2 O 3 ) was studied as a host material for the divalent europium ion. Polycrystalline samples of Eu 2 þ -doped translucent Al 2 O 3 were fabricated, and room temperature luminescence behavior was observed. Al 2 O 3 ceramics doped with 0.1 at% Eu 2 þ were fabricated with a relative density of 99.75% theoretical density and in-line transmittance of 22% at a wavelength of 800 nm. The ceramics were processed by a gel-casting method, followed by sintering under high vacuum. The gelling agent, a copolymer of isobutylene and maleic anhydride, is marketed under the commercial name ISOBAM, and has the advantage of simultaneously acting as both a gelling agent and as a dispersant. The microstructure and composition of the vacuum-sintered Eu 2 þ :Al 2 O 3 were characterized by Scanning Electric Microscopy (SEM), Transmission Electron Microscopy (TEM), and Energy-dispersive X-ray spectroscopy (EDS). The phase composition was determined by X-ray diffraction measurements (XRD) combined with Rietveld analysis. The photoluminescence behavior of the Eu 2 þ :Al 2 O 3 was characterized using UV light as the excitation source, which emitted blue emission at 440 nm. The radio-luminescence of Eu 2 þ :Al 2 O 3 was investigated by illumination with X-ray radiation, showing three emission bands at 376 nm, 575 nm and 698 nm. Multiple level traps at different depths were detected in the Eu 2 þ :Al 2 O 3 by employing thermoluminescence measurements.

Reduction of Eu3+ to Eu2+ in α-Y2Si2O7 and X1-Y2SiO5 and their luminescent properties

“…The charge compensation is expected to occur through the formation of oxygen vacancies, which are common in a reducing atmosphere [14,28].In addition, it has been widely reported that this band is related with the 5݀ → 4݂ allowed transition of Eu 2+ ions. The reduction of europium in matrixes formed by trivalent cations and even the presence of a similar band due to Eu 2+ in the Y 2 Si 2 O 7 lattice is found in literature [14,28,33].…”

Investigation of room‐temperature super‐stabilized suspension casting system mechanism

“…Recently, a novel casting system using a water‐soluble, alternating block co‐polymer of isobutylene and maleic anhydride (see Figure ) (trade name: ISOBAM [#104, Kuraray America, Elastomer BU]) has gained interest. It is particularly advantageous because it uses one organic component that purportedly acts as both a binder and a dispersant, while producing dense green bodies with homogenous microstructures at high solids loading (up to 55 vol%), low added organic content (~0.1%‐1%), and low shrinkage and cracking …”

Structural and optical study of Fe3+‐doped Al2O3 nanocrystals prepared by new sol gel precursors

“…The catalytic, optical, and structural properties of alumina can be enhanced by doping small amounts of one of the transitional elements including Mn, Zn, Fe, and Cu. Among these transition metals, iron dopant in aluminum oxide improved its catalytic and magnetic properties owing to the increase in surface‐to‐volume ratio . When Fe 3+ ions lie at the alumina surface the absorptivity increases in relation to the volumetric state because of the addition of iron dopant.…”