Lanthanide ions photonics

Lanthanides activated luminescent materials are widely used for solid-state lasers, luminescent lamps, flat displays, optical fiber communication systems, and other photonic devices. It is because of the unique solid-state electronic properties that enable lanthanide ions in solids to emit photons efficiently in visible and near IR region. Due to the pioneer work by Dieke, Judd, Wyboume, and others in theoretical and experimental studies of the... 

Carboxylates With the aim of developing highly luminescent Er111 complexes for advanced photonic applications, some of the research concentrates on the synthesis of new ligands, based on simple molecular frameworks such as alkyl chains or benzene rings fitted with carboxylate groups for coordination to the lanthanide ions. For instance, the photophys-... 

Lanthanide ion lumophores have also been included in receptor,-spacer-receptor systems outside of the PET design principle. Nocera has targeted ionic or nonionic aromatic guests.187-189 The aromatic character of the guest is critical since receptor2 (as we as receptor,) is chosen to be optically transparent in this scheme. Since the guest serves to receive photonic excitation for subsequent EET to the lanthanide lumophore, the guest switches the luminescence on. ... 

Extension to the use of multi-photon induced luminescence lanthanide-based bioprobes adds new possibilities and challenges to the field. However, there are even fewer examples of multiphoton lanthanide bioprobes because achieving acceptable quantum yields is fairly difficult in view of the numerous nonradiative deactivation pathways created by a wealth of vibrations, including high energy oscillators located far from the emitting lanthanide ion. 

The unique luminescent properties of rare earth metal clathrochelates have been used in the development of luminescent materials (luminophores and laser materials). The luminescence of these clathrochelates in solution makes their application as biological probes and concentrators of the luminescence (i.e., the antenna effect ) promising. These complexes can also serve as efficient molecular devices to convert UV light absorbed by the ligand to lanthanide ion luminescence in the visible region. Even in very dilute (10-5 mol l-i) solutions, the conversion of irradiated photons to luminescent ones has been observed to occur at a rate of approximately 1%. For rare earth metal aqua ions at the same concentration, the efficiency of conversion is equal to 4 x IQ- % [212, 390-392]. 

Lanthanide ions exhibit long-lived, strong luminescence in the visible region. Their f f absorption bands are, however, very weak and FRET to lanthanide ions is thus inefficient. Efficient FRET and even two-photon absorption118 can be achieved by complexation with appropriate chromophores as an antenna. Lanthanide ion complexes (Figure 2.21) are used... 

In principle, all possible excitations contribute to the photoelectron spectrum and the proper quantum mechanical amplitude must be calculated. For the lanthanides, the atomic limit corresponds to the assumption that the photoelectron spectrum is dominated by those processes, where the photon hits a particular ion and causes an excitation on that ion without disturbing the remainder of the crystal. In the standard model, the lanthanide ion would initially be in its bivalent / configuration with the Hund s rule ground state multiplet (Table 1 in Section 2.2), and would be transferred into some multiplet within configuration... 

Another important parameter is the photostabUity of the luminophores as this determines the total number of photons that will be emitted by the complex before it is destroyed by a photoinduced process. Data on the photostability of lanthanide complexes is very scarce. The photostabUity of lanthanide complexes is expected to be superior to that of organic fluorophores since the excitation energy only remains on the organic ligand a very short time before it is transferred to the lanthanide ion, which usually does not undergo any photochemical transformations. 

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