کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10623938 989582 2016 34 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Electrical properties and light up conversion effects in Bi3.79Er0.03Yb0.18Ti3−xWxO12 ferroelectric ceramics
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Electrical properties and light up conversion effects in Bi3.79Er0.03Yb0.18Ti3−xWxO12 ferroelectric ceramics
چکیده انگلیسی
Modified ceramic compositions of Bi3.79Er0.03Yb0.18Ti3−xWxO12 with fixed Er and Yb content, and a varying W content (x=0.0, 0.01, 0.03, 0.06 and 0.10) are prepared. The site selectivity of Er3+, Yb3+, and W6+ cations is analyzed, and their influence on the electrical and light up conversion properties is studied. Formation of single phase orthorhombic structure is confirmed with enhanced grain growth up to x=0.03, and for (x≥0.04-0.10) the grain growth is inhibited, and the orthorhombic distortion is relaxed. Raman spectroscopy reveals W6+ cation substitutes preferentially at the B-site replacing Ti4+ ions in the Bi4Ti3O12 lattice structure. Increasing W6+ donor concentration reduces the conductivity effects by lowering the oxygen vacancies. Reduced dielectric losses (tan δ=0.003) and dispersion with frequency in the range (10−2-10 Hz) are observed, and improvements in the remnant polarization (2Pr=28.86 μC/cm2) are seen up to an optimum content of x=0.03. At higher W content (x>0.03), the properties tend to degrade due to structural relaxation and microstructural changes. Up conversion photoluminescence (UC-PL) under 980 nm excitation shows strong emission in the green and red bands due to enhanced crystal field around the Er3+ ions for an optimum W content of x=0.06. A weak blue emission band around (~492 nm) is observed by cooperative emission (CE) due to radiative relaxation of an excited Yb-Yb pair from a virtual level. Variation of UC emission intensity with pump-power confirms a two-photon mechanism for the up conversion process.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ceramics International - Volume 42, Issue 5, April 2016, Pages 5718-5730
نویسندگان
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