scholarly journals Dynamics of the Green and Red Upconversion Emissions inYb3+-Er3+-CodopedY2O3Nanorods

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
O. Meza ◽  
L. A. Diaz-Torres ◽  
P. Salas ◽  
C. Angeles-Chavez ◽  
A. Martínez ◽  
...  

Efficient green and red upconversion emission inY2O3:Yb3+,Er3+nanorods under 978 nm radiation excitation is achieved. Experimental effective lifetimes, luminescent emissions, and nanorod sizes depend strongly on the solvent ratios used during the synthesis. A microscopic nonradiative energy transfer model is used to approach the dynamics of the green, red, and infrared emissions. The excellent agreement between simulated and experimental decay suggests that the energy transfer mechanisms responsible of the visible emission depend on the solvent ratio.

1992 ◽  
Vol 46 (9) ◽  
pp. 1376-1381 ◽  
Author(s):  
Huei-Yang D. Ke ◽  
Gary D. Rayson

The emission spectra and fluorescence decay curves of solid UO2+2- Datura at liquid nitrogen temperature have been measured. The linewidth of the emission peaks of UO2+2 ions in UO2+2- Datura decreases with the UO2+2 concentration. This linewidth broadening phenomenon can be explained by the existence of resonance interactions between adjacent UO2+2- Datura species. The analysis of the emission peak position of the bound ions has been used to provide a measure of the electronic factors contributing to the interaction between the uranyl ion and phosphoryl and dicarboxyl moieties on the cell wall material. An observed blue shift of the uranyl fluorescence spectrum as a function of solution pH has been ascribed to a distortion of the normally linear O-U-O bond. An inter- and intra-molecular nonradiative energy transfer model has been successfully used to interpret the measured lifetime data of UO2+2- Datura.


2009 ◽  
Vol 5 ◽  
pp. 121-134 ◽  
Author(s):  
O. Meza ◽  
L.A. Diaz-Torres ◽  
P. Salas ◽  
E. De la Rosa ◽  
C. Ángeles-Chávez ◽  
...  

The concentration luminescence quenching of the NIR emission of Yb3+ in nanocrystalline ZrO2 is studied. It is found that the quenching is dominated by cooperative energy transfer processes from isolated Yb3+ ions to Yb-Yb pairs (Yb dimers). The Yb dimer concentration depends on the crystallite phase and size, which on time depends on Yb concentration. An extended energy transfer model was developed to predict the IR and cooperative visible fluorescence emissions by taking in to account the crystalline phase, the nanocrystals size, and the geometrical construction of Yb dimers. Our model succeeds to fit simultaneously both experimental VIS and NIR emissions, and the corresponding interaction parameters are reported.


2013 ◽  
Vol 401-403 ◽  
pp. 1149-1152
Author(s):  
Yan Chen ◽  
Xian He Huang

To improve the accuracy of quartz crystal microbalance (QCM) immunosensor, it is the key to distinguish accurately and effectively about the effects of mass loading and damping loading of a quartz resonator vibrating in damping environment. The energy transfer model (ETM) is introduced to deduce functional relationship between the product of absolute viscosity and density of the liquid deposit and the maximum amplitude of vibration at the quartz-resonator surface. Then the effect of mass loading can be rapidly distinguished from damping loading by measuring the frequency shift and the amplitude of QCM. This method provides a new theoretical basis for the application of QCM immunosensor in medical diagnosis, especially in tumor diagnosis.


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