کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1522118 | 1511815 | 2014 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Effect of charge compensation on up-conversion and UV excited luminescence of Eu3+ in Yb3+-Eu3+ doped calcium aluminate CaAl4O7
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
مواد الکترونیکی، نوری و مغناطیسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Calcium aluminate powders co-doped with Yb3+ and Eu3+: Ca1âxâyYbxEuyAl4O7 (x = 0.02-0.06; y = 0.02), Ca1âxâyYbxEuyAl4O7 (x = 0.05, y = 0.01-0.07) were synthesized by a modified Pechini citrate process and their optical properties at 298 K and 77 K were investigated. Direct excitation of Yb3+ by means of 2F7/2 â 2F5/2 absorption at 980 nm leads to bluish-green luminescence centered around 488 nm due to the cooperative emission of Yb3+ and red emission of Eu3+ corresponding to 5D0 â 7FJ (J = 0-4) transitions. The near-infrared to red up-conversion luminescence of Eu3+ was assigned to a cooperative sensitization mechanism. The effect of activators concentration and charge compensation by co-doping with Na+ ions on luminescence properties were studied in detail. Na+ addition led to narrowing of luminescence bands, suggesting smaller disturbance/distribution of activator ions local symmetries. This was associated with significantly enhanced luminescence brightness of Eu3+ under UV excitation and, surprisingly, with noticeably reduced efficiency of Eu UC emission upon near-infrared excitation. It was also concluded that Yb3+ pairs transfer preferentially their excitation energy to Eu3+ ions with the local symmetry perturbed by certain defects present in the crystal lattice.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Chemistry and Physics - Volume 147, Issues 1â2, 15 September 2014, Pages 304-310
Journal: Materials Chemistry and Physics - Volume 147, Issues 1â2, 15 September 2014, Pages 304-310
نویسندگان
M. Puchalska, E. Zych, M. Sobczyk, A. Watras, P. Deren,