Luminescence of lanthanide ions

Luminescence of Lanthanide Ions in Coordination Compounds and Nanomaterials... 

Three types of transitions luminescence of lanthanide ions ... 

Another way for turning on the luminescence of lanthanides ions is the encapsulation of macrocyclic Eu(iii) chelates by discrete, monodisperse SiOj nanoparticle. The free complex, see Fig. 14, exhibits primarily weak ligand-derived emission at room temperature, typical for these compounds, and displays intense metal-centered luminescence from the Eu only in rigid matrix at 77 K. Upon encapsulation by the NPs, Eu-derived luminescence is switched on at room temperature, yielding strong emission bands characteristic of Eu(m) complexes with a corresponding enhancement factor of 6 x... 

Quantum yield measurements are simple in their principle, but very difficult to carry out experimentally, particularly when it comes to the luminescence of lanthanide ions and to intrinsic quantum yield, f-f absorptions being faint. There are two main methods the comparative method in which the sample under examination is compared to a standard with known quantum yield, and the absolute method which... 

The luminescence of lanthanide ions in solids has been the subject of several books or chapters [1-12] and has an immense scope. Since 1 was asked to write this review within a short time, I have failed to give a comprehensive survey but have given a qualitative overview of several areas with some references to more quantitative treatments. Topics such as lanthanide luminescence of laser materials [4,8,13,14], sensors [15], hybrid materials [16], organolanthanide, and coordination compounds [17] are missing. So what is here in October 2009 - basically, a description of the luminescence spectra of lanthanide ions in the solid state and some applications of phosphor materials. 

The luminescence of lanthanide ions in solids is characterized by several types of electronic transition, which differ markedly in spectral intensity and linewidth. Some of these are now illustrated. 

The luminescence of Ln ion from the f-f transitions can be classified as two types of transitions the parity-allowed magnetic dipole transitions and the parity-forbidden electric dipole transitions. When the Ln " ion is inserted into a chemical enviromnent, noncentrosymmetric interactions allow the mixing of electronic states of opposite parity into the 4f wave functions, and electric dipole transitions become partly allowed. The intensity of some of these transitions is particularly sensitive to the nature of the metal ion environment, and these transitions are called hypersensitive transition a typical example is the Dq p2 transition of Eu [106]. Thus, the luminescence of lanthanide ions can provide valuable information about the local enviromnent and make them very suitable for acting as a structural probe deciphering the symmetry of the chemical environment and the coordination sphere. 

Luminescence of Lanthanide ions in Coordination Compounds and Nanomaterials Table 1.5 Expectation values in a.u. [38]... 

Luminescence of Lanthanide Ions In Coordination Compounds and Nanomaterials Table 1.9 Selected doubly reduced matrix elements yfrsrWu Wv rs L ) for the f Pr ion [34 ... 

Luminescence of Lanthanide Ions in Coordination Compounds and Nanomaterials below, as demonstrated in Section 1.3.4 ... 

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