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http://cio.repositorioinstitucional.mx/jspui/handle/1002/390| SYNTHESIS AND CHARACTERIZATION OF OXIDES AND FLUORIDES DOPED NANOCRYSTALS WITH UV-VIS-NIR EMISSION | |
| ALEJANDRA URBINA FRIAS | |
| ELDER DE LA ROSA | |
| Acceso Abierto | |
| Atribución-NoComercial-SinDerivadas | |
| NANOMATERIALS, NANOPHOSPHORS, NANOCRYSTALS, LUMINESCENCE, RARE EARTH, SCANNING ELECTRON MICROSCOPY, UP CONVERSION EMISSION | |
| "In this thesis is presented a study of structural, morphological and optical properties of lanthanide-doped nanocrystalline oxides and fluorides. Ytterbium (Yb3+), Erbium (Er3+), Gadolinium (Gd3+), Bismuth (Bi3+), Boron (B3+), Europium (Eu3+), Holmium (Ho3+), and praseodymium (Pr3+) doped and co-doped ZrO2, Y2O3, Y2O2S, and NaYF4 were studied under UV and IR excitation. Most lanthanidedoped oxides were prepared by precipitation method combined with a hydrothermal process, and a few by combustion method. The crystal structure was investigated by X-Ray diffraction, and it was obtained tetragonal phase, cubic phase, and hexagonal phase for the lanthanide-doped and codoped ZrO2, Y2O3 and Y2O2S, respectively; two mixed phases, cubic and hexagonal were presented in lanthanides NaYF4. ZrO2: Yb3+, Er3+, Gd3+ nanocubes were synthesized with Na2S, where the enhancement of the UC signal with the use of Na2S was the result of the substitution of OH- by SO42- ions on the surface of nanoparticles. While the strong enhancement observed with the introduction of Gd3+ was the result of a forward and backward energy transfer process (Er3+ → Gd3+ → Er3+). Such increments are explained in terms of the surface passivation by using Na2S during the synthesis process and the role of Gd3+ as a reservoir of energy from Er3+. Tridoped ZrO2:Yb3+-Er3+-Bi3+ nanophosphors were synthesized and demonstrated the possibility to switch from green yellow to red emission by switching the excitation from 350 nm to 970 nm. The red band produced by the relaxation of transition 4F9/2+ 4I15/2 of Er3+ was enhanced by a factor of 3 as a result of the forward and backward energy transfer process (Er3+Bi3+Er3+). Also, it was observed NIR emission which was enhanced with the introduction of Bi3+ ion. It was obtained Y2O3: Yb3+, Er3+, M3+ (M3+: Bi3+, Gd3+, Eu3+, Ho3+, Pr3+) nanoparticles with cubic crystalline phase, under precipitation method combined with a hydrothermal process, and combustion synthesis. Besides enhancing considerably the intensity of luminescence, Bi3+ and Gd3+ present own emissions." | |
| 2016-02 | |
| Tesis de doctorado | |
| Inglés | |
| León, Guanajuato | |
| Público en general | |
| Urbina-Frías, (2016). "Synthesis and characterization of oxides and fluorides doped nanocrystals with UV-VIS-NIR emission". Tesis de Doctorado en Ciencias (Óptica). Centro de Investigaciones en Óptica, A.C. León, Guanajuato. 161 pp. | |
| ÓPTICA | |
| Aparece en las colecciones: | DOCTORADO EN CIENCIAS (ÓPTICA) |
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