کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1692090 | 1510775 | 2016 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Photoluminescence of carbon dots from mesoporous silica
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
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چکیده انگلیسی
Photophysical properties of carbon dots were investigated under various excitation conditions and over a wide temperature region - from room to liquid helium temperatures. The carbon dots (CDs) were synthesized using mesoporous silica particles as a reactor and (3-aminopropyl)triethoxysilane (APTES) as a precursor. The photoluminescence spectra of CDs exhibit a strong dependence on the excitation wavelength and demonstrate a significant inhomogeneous broadening. Lowering sample temperature reveals the doublet structure of the spectra, which is associated with the vibronic structure of radiative transitions. The vibration energy â¼1200 cmâ1 is close to the energy of CO stretching vibration. Long-lived phosphorescence of carbon dots with its decay time â¼0.2 s at T = 80 K was observed. The fluorescence and phosphorescence spectra are shown to be spectrally separated. The long-lived component of the emission was ascribed to optically forbidden triplet-singlet transitions. The value of the singlet-triplet splitting was found to be about 0.3 eV. Photo-induced polarization of the luminescence of carbon dots was revealed. The degree of the linear polarization is dependent on the wavelengths of both excitation and emitted light. The effect indicates a hidden anisotropy of optical dipole transitions in the dots and demonstrates the loss of the dipole orientation during the electron energy relaxation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Optical Materials - Volume 59, September 2016, Pages 28-33
Journal: Optical Materials - Volume 59, September 2016, Pages 28-33
نویسندگان
D.K. Nelson, B.S. Razbirin, A.N. Starukhin, D.A. Eurov, D.A. Kurdyukov, E. Yu Stovpiaga, V.G. Golubev,