Lanthanide hybrids

For technological applications, the NIR-luminescent lanthanide complexes have to be incorporated into a stable matrix because of their poor thermal stability and low mechanical strength. So far, the incorporation of luminescent lanthanide complexes in matrices, as a result, the NIR-luminescent lanthanide hybrid materials, is of widespread interest in material science as it allows construction of functional materials with various optical properties. The study of NIR-luminescent lanthanide complexes in hybrid materials is not only of fundamental interest but these materials also have a high potential for different applications (optical amplifiers, optical waveguides, OLEDs, etc.). In general, these hybrid materials have superior mechanical properties and have a better processability than the pure lanthanide complexes. Moreover, embedding a lanthanide complex in a hybrid matrix is also beneficial for its thermal stability and luminescence output. ... 

In conclusion, recent research progress on the photofunctional rare earth materials based on ionic liquids has been summarized, which mainly consist of two important classes one is the rare earth compounds dispersed or dissolved in ionic liquids, even including the rare earth compounds of ionic liquids with exact crystal structures the other is the photofunctional rare earth hybrid materials using ionic liquids both as the chemical linkers and host. However, some problems still exist in the field of photofunctional rare earth materials based on ionic liquids. The first problem is the controlled preparation and fabrication of thin film materials of ionic gels based on luminescent rare earth compounds, which is important and necessary for the further applications in optical devices. The second problem is luminescent enhancement and functional integration of the photofunctional rare earth materials based on ionic liquids. Here it is worth pointing out that it is important to develop visible-excitation lanthanide hybrid system and obtain white luminescence through multicomponent assembly of rare earth species and ionic liquids. 

Lanthanides also have potential as DEFRET energy donors. Selvin et al. have reported the use of carbostyril-124 complexes (53) with europium and terbium as sensitizers for cyanine dyes (e.g., (54)) in a variety of immunoassays and DNA hybridization assays.138-140 The advantage of this is that the long lifetime of the lanthanide excited state means than it can transfer its excitation energy to the acceptor over a long distance (up to 100 A) sensitized emission from the acceptor, which occurs at a wavelength where there is minimal interference from residual lanthanide emission, is then measured. 

Lanthanide ions offer several salient properties that make them especially attractive as qubit candidates (i) their magnetic states provide proper definitions of the qubit basis (ii) they show reasonably long coherence times (iii) important qubit parameters, such as the energy gap AE and the Rabi frequency 2R, can be chemically tuned by the design of the lanthanide co-ordination shell and (iv) the same molecular structure can be realized with many different lanthanide ions (e.g. with or without nuclear spin), thus providing further versatility for the design of spin qubits or hybrid spin registers. 

Escribano P, Julian-Lopez B, Planelles-Arago J et al (2008) Photonic and nanobiophotonic properties of luminescent lanthanide-doped hybrid organic-inorganic materials. J Mater Chem 18 23-40... 

In light lanthanides (La, Ce, Pr, Nd) the pulled down 4f state is nearly localized and hybridizes only weakly with conduction states. The bandwidth W4f will be very narrow, U high and negative, and the occupation probabiUty by conduction electrons rather low. This results in the occurrence of shake-down satellites at a lower binding energy for lanthanides, accompanying a poorly screened main peak (Fig. 7 a). When proceeding to heavier lanthanides, the occupation probability and the intensity of the shake-down satellite are depressed the symmetric, poorly screened core level is left, i.e. the 4f states are completely localized. 

The 6 d-5 f hybridization of the conduction bands of light actinide metals, which is also predicted by theory, is also demonstrated in photoelectron spectra of Th, U and Pu. In Am metal, on the contrary, the emission at Ep is foimd to be non-f-like, as expected for a lanthanide-like actinide. 

Time-resolved RET is capable of very sensitive detection of DNA hybridization. With a lanthanide chelate as the donor and an organic fluorophore like tetramethylrhodamin as the acceptor, time-resolved measurements can indicate the hybridization by strong changes in the intensity decay of the donor [186]. The development of new dyes for time-resolved RET with improved properties still is a major task [187,188]. But, so far, the detection of biomolecular interactions by time-resolved RET has not entered real applications in the DNA or protein array market. 

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