CeO :Er3+ i an las n l 15/2 sity nsm these results were presented, respectively. 2015 Elsevier B.V. All rights reserved. cubic l stab cm1 ation, a iative and vacuum sintering method, many transparent ceramics, such as Y3Al5O12, MgAl2O4, Y2O3, Lu2O3, Sc2O3, and ZrO2, have been successfully fabricated [7–12]. To our best knowledge, there is still no reported work on the fabrication of transparent CeO2 ceramics.
Upconversion materials possess potential applications in solid state visible lasers, biological fluorescence labels, or
CeO2:1%Er, CeO2:1%Er, 5%Li and CeO2:1%Er, 10%Li nanoc were synthesized by glycine-nitrate gel-combustion m
Ce(NO3)3 (AR), Er2O3 (99.99%) and LiNO3 (AR) were used as starting materials. Firstly, a given amount of Er2O3 was dissolved with concentrated HNO3 to convert into Er(NO3)3 solution. The respective nitrate solutions with a cationic molar ratio for Ce3+:Er3+:Li+ of 0.99:0.01, 0.94:0.01:0.05, 0.89:0.01:0.10 and amount of glycine were mixed in a crucible, and boiled to dehydration. The mixture then ignites and the combustion process lasts only a few seconds. ⇑ Corresponding author. Tel./fax: +86 792 8337989.
E-mail address: email@example.com (D. Wang).
Optical Materials xxx (2015) xxx–xxx
Contents lists availab
Optical M .e lsbroad practical applications than that of the powders. However, it is extremely difficult to grow large-size CeO2 single crystal with high quality because of its very high melting point (2400 C). Fortunately, by newly developed nanocrystalline powder technology excitation. 2. Experimentalhttp://dx.doi.org/10.1016/j.optmat.2015.01.033 0925-3467/ 2015 Elsevier B.V. All rights reserved.
Please cite this article in press as: Y. Guo et al., Opt. Mater. (2015), http://dx.doi.org/10.1016/j.optmat.2015.01.033rystals ethod.result in a high quantum yield of upconversion process. Many recent studies have been carried out on the upconversion luminescence in CeO2:Er3+ nanopowders, CeO2:Er3+, Yb3+ nanorods, CeO2:Er3+, Tm3+, Yb3+ inverse opals, three-dimensional ordered macroporous (3DOM) CeO2:Er3+, Yb3+, and CeO2:Er3+, Yb3+ phosphors using 976–980 nm diode laser or 785 nm laser excitation [1–6]. But it is obvious that bulk transparent materials have more ble green and red upconversion emissions in Er /Yb :Y2O3 nanocrystals with Li+ ions tridoping are about 2 orders of magnitude higher than previous results [19–23].
In the present paper, CeO2:Er and CeO2:Er, Li translucent ceramics were fabricated for the first time. The effect of Li+ ions doping on microstructure and upconversion emission of CeO2:Er translucent ceramics were investigated under the 980 nm laser diode2 1. Introduction
Cerium oxide (CeO2) exists in the structure, and has excellent therma and low phonon cutoff energy (465 makes it suitable for practical applic decrease the possibility of nanoradform, having a fluorite ility, chemical stability ). The former property nd the later one would transitions and in turn three-dimensional volumetric displays [13–18], in which visible or UV light is generated from lower energy radiation through the doping of rare earth or transition metal ions. The trivalent erbium ion (Er3+) is a promising active ion for upconversion applications, as its energy level structure favors a lot of upconversion processes.
In recent years, the photoluminescence enhancement of Li+ doped materials has been investigated extensively. For instance, the visi3+ 3+Ceramics
Microstructure when Li ions were introduced as ceramics fluxing agent. The effect of Li ions doping on microstructure and upconversion emission of CeO2:Er translucent ceramics was investigated and the possible reasons forEffect of Li+ ions doping on microstructu luminescence of CeO2:Er3+ translucent ce
Yanyan Guo a, Dianyuan Wang b,⇑, Fang Wang a aCollege of Mechanical and Materials Engineering, Jiujiang University, Jiangxi 332005, P bCollege of Science, Jiujiang University, Jiujiang 332005, PR China a r t i c l e i n f o
Received 6 December 2014
Received in revised form 20 January 2015
Accepted 21 January 2015
Available online xxxx
Keywords: a b s t r a c t
CeO2:1%Er, CeO2:1%Er, 5%L
Under the 980 nm diode (640–680 nm) upconversio 4S3/2? 4I15/2 and 4F9/2? 4I version luminescence inten vation suggests that the tra + journal homepage: wwwmics ina d CeO2:1%Er, 10%Li translucent ceramics were fabricated for the first time. er excitation, the ceramics gave intense green (520–570 nm) and red uminescence, which were ascribed to the radiative transitions of 2H11/2, of Er3+ ions, respectively. It was worthy to point out that the above upconof CeO2:Er, Li ceramics was greatly enhanced, and the preliminary obserittance of CeO2:Er, Li ceramics in the visible spectral region was improved +and upconversion le at ScienceDirect aterials evier .com/locate /optmat
The voluminous and foamy product can be easily milled, becoming the precursor nanocrystalline powder of CeO2:Er and CeO2:Er, Li.
The dried precursors were calcined at 800 C for 1 h in air. Then the as-prepared nanocrystalline powders were uniaxially coldpressed into pellets in a steel die under 50 MPa pressure for 30 min. Such pellets were sintered in a furnace into translucent ceramics at 1100 C for 10 h in air.
The crystalline structure was identified using an X-ray diffractometer (SHIMADZU XD-D1, Rigaku, Japan) with Cu Ka-radiation.
The morphology and particle size of the powders were analyzed by a transmission electron microscope (Tecnai G2 20, FEI,
Netherlands). The microstructure of the ceramics was studied by a scanning electron microscope (VEGA II LSU, Tescan, Czech Republic). The upconversion emission spectra were measured and analyzed by using a fluorescence spectrometer (F-4500, Hitachi,
Japan) under 980 nm diode laser (Newport, USA, 100–500mW) excitation at room temperature. 3. Results and discussion
The XRD patterns of the products (Ce0.99xEr0.01Lix)O2 nanopowders calcined in air at 800 C for 1 h are presented in Fig. 1. It is apparent that the patterns exhibit the samples crystallized in face-centered cubic fluorite crystal structure (JCPDS 81-0792). In