کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9778019 | 1510568 | 2005 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Luminescence activity of surface and interior Ge-oxygen deficient centers in silica
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
We report a comparative study on the optical activity of surface and interior Ge-oxygen deficient centers in pressed porous and sol-gel Ge-doped silica, respectively. The experimental approach is based on the temperature dependence of the two photoluminescence bands at 4.2 (singlet-singlet emission, S1 â S0) and 3.1 eV (triplet-singlet emission, T1 â S0), excited within the absorption band at about 5 eV. Our data show that the phonon assisted intersystem crossing process, linking the two excited electronic states, is more effective for surface than for interior centers in the temperature range 5-300 K. For both centers, a distribution of the activation energies of the process is found. Based on the results of quantum chemical calculations of the electronic structure of (HO)2Ge: molecule it is suggested that the electronic de-excitation pathway involves two excited triplet states (S1 â T2 â T1 â S0) and shows a structural dependence on the O-Ge-O angle.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Crystalline Solids - Volume 351, Issues 21â23, 15 July 2005, Pages 1805-1809
Journal: Journal of Non-Crystalline Solids - Volume 351, Issues 21â23, 15 July 2005, Pages 1805-1809
نویسندگان
A. Cannizzo, S. Agnello, S. Grandi, M. Leone, A. Magistris, V.A. Radzig,