Synthesis and Characterization of Yttrium Titanate and Er doped Yttrium Titanate Nanofibers
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Synthesis and Characterization of Yttrium Titanate and Er doped Yttrium Titanate Nanofibers Kanchan Mondal1, Kaleb Hartman1, George Trifon1, Debalina Dasgupta2, Matthew Bolin1, Mallika Dasari3, Chung Ying Tsai1 1
Department of Mechanical Engineering and Energy Processes, Southern Illinois University, Carbondale, IL Illinios Clean Coal Institute, Carterville IL Department Of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL
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ABSTRACT Yttrium titanate belongs to a family of compounds called pyrochlores with significant properties such as ionic conduction, optical non-linearity and radiation tolerance that have resulted in applications thermal barrier coatings, high-permittivity dielectrics, and materials for safe disposal of actinide-containing nuclear waste, and hydrogen storage material. The application of these materials in ODS ferritic steels, photocatalytic water splitting and a more efficient host material than TiO2 for Er3+ luminescence have been evaluated. ErxY2-xTi2O7 has tremendous applications in fiber amplifiers, integrated optical devices and selective emitters for thermophotovoltaic applications. Since 1-D nanostructures are deemed to be important building blocks for future optical and optoelectronic nanodevices, we have used electrospinning methods to synthesize nanofibers and freestanding, non-woven nanofibers membranes of single phase yttrium titanate and ErxY2-xTi2O7 (Er/(Ti+Er) at. ratio= 0 -15 %) with diameters less than 150 nm and have characterized the physical, thermal and optical properties of these nanofibers. INTRODUCTION The pyrochlore subgroup minerals are classically represented by A2-mB2X6-wZ1-n and exhibit a space group Fd3m with a unit cell characterized by a § 10.4 Å and Z=8. In this formula, A is a large 8-coordinated cation. Although A is generally a trivalent cation, it may accommodate mono, divalent cation and H2O (sites 16d and 96g). B is a 6-coordinated cation (site 16c) while X is generally O, although it can include OH and F (site 48f). Finally, Z is typically an anion such as O, but can also include a vacancy, H2O or a very large (>>1.0 Å) monovalent cation (site 8b). Subscripts m, w and n are parameters referring to the incomplete occupancy of A, X and Z sites with values ranging from 0 to 1.7, 0 to 0.7 and 0 to1, respectively. It has been reported that the value of m can range up to even two. Generally, A2B2O7 is the accepted formula for pyrochlores. Due to their unique structural properties, pyrochlores have the potential of high chemical stability, high catalytic activity and excellent ion conductivity. Yttrium titanate (Y2Ti2O7) is one such pyrochlore and has received considerable attention in recent years. They have many potential applications, including thermal barrier coatings (Vassen et al, 2008), highpermittivity dielectrics (Ren et al, 2001), solid electrolytes in solid-oxide fuel cells (Wuensch et al, 2000) and materials for safe disposal of actinide-containing nuclear waste (Ewing et al, 2004). Investigations into the thermal propertie
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