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A series of heteroleptic bis(phthalocyaninato) europium(lll) complexes with one, two, three and four 15-crowns-5 voids attached at different positions of one of the two phthalocyninato ligands in the double-decker molecules are devised and prepared by Eu(Pc)(acac)-induced (Hacac = acetylacetone) mixed cyclization of the two corresponding phthalonitriles. Their electrochemistry and supramolecular structure-formation properties are studied.

A europium(III) DO3A-tris(amide) complex is described for imaging pH by MRI by using ratiometric chemical exchange saturation transfer (CEST) principles. The collection of two CEST images at two slightly different activation frequencies has provided a direct readout of solution pH without the need of a concentration marker.

Gadolinium doped europium sulfides ([Eu.sub.1-x][Gd.sub.x]S) are prepared by the thermal decomposition of the precursors Eu[([S.sub.2]CN[Et.sub.2]).sub.3]Phen/Gd[([S.sub.2]CN[Et.sub.2]).sub.3]Phen. The magnetic properties have helped in determining that the paramagnetic Curie temperature has varied with doping level, in a similar way to [Eu.sub.1-x][Gd.sub.x]O displaying an increase at low doping levels.

A near UV excitable phosphor [Sr.sub.2.85][Eu.sub.0.1][Al.sub.0.9][In.sub.0.1][O.sub.4-[alpha]][F.sub.1-[delta]] is made by reducing as-made [Sr.sub.2.85][Eu.sub.0.1][Al.sub.0.9][In.sub.0.1][O.sub.4]F, which has disclosed defect-induced broad-band photoluminescence emissions. The combined line and broad-band emitters have the potential when combined with another broad-band emitting phosphor to create white light by converting near-UV light from a [Ga.sub.1-x][In.sub.x]N light-emitting device.

The role of [Ce.sup.3+] concentration on the luminescence intensity of [Eu.sup.3+] in [Ce.sup.3+]- and [Eu.sup.3+]-doped YP[O.sub.4] is examined. A luminescent study is performed for the first time with a change of solvent from [H.sub.2]O to [D.sub.2]O and remarkable improvement is found in luminescence.

A hybrid chemical solution method is developed for preparing nanocomposite thin films composed of a ferroelectric [Bi.sub.3.6][Eu.sub.0.4][Ti.sub.3][O.sub.12] (BEuT) matrix and highly c-axis-oriented ZnO nanorods on Si substrates. The studies have helped in realizing highly efficient photoluminescent ferroelectric multifunctional integrated thin-film devices and the method has provided a new route for preparing new nanocomposite thin films consisting of other inorganic matrix and c-axis-oriented ZnO nanorods.

A new method is described for measuring the absolute standard hydrogen electrode (SHE) potential in which reduction energies of Eu[([H.sub.2]O).sub.n.sup.3+] (n = 55 to 140) are extrapolated as a function of the geometric dependence of the cluster reduction energy to infinite size. The results have shown that the environment of [Eu.sup.3+] in these nanodrops and the surface potential of the nanodrops are comparable to those of the condensed phase.

The synthesis, properties and the applications of the highly versatile rare earth tantalate pyrochlore nanophosphors are discussed. These materials are shown to be widely used in numerous energy and environment related applications, including the batteries and the fuel cells.

A double-superimposed charge density wave (CDW) distortion with modulation vectors oriented in the same direction seen in the square net of [Cu.sub.0.63]Eu[Te.sub.2] has represented the example of its kind among CDW materials with electronic Fermi surface instabilities.

The existence of a filling fraction limit (FFL) for single-element filling in caged compounds such as Co[Sb.sub.3] is established as a general phenomenon. The electronic structure analysis has shown that the Na-Eu cofilling has pushed the s states of Na and Eu closer to the bottom of the conduction band, increased the electron occupancy of these s orbitals, lowered the effective charge states of the fillers, affected the Na-Eu interaction and has led to the anomalous filling behavior.

[Bi.sub.4-x][Eu.sub.x][Ti.sub.3][O.sub.12] (BEuT) ferroelectric thin films are prepared on SrTi[O.sub.3] (STO) substrates with different orientations by using chemical solution deposition and the effects of Eu ion concentration crystallographic orientation on the photoluminescent property are examined. The orientation dependent photoluminescence is attributed to low light scattering of well-aligned grains with c-axis oriented growth.

The luminescence and phosphorescence properties of strontium aluminates, [Sr.sub.4][Al.sub.14][O.sub.25]:[Eu.sup.2+] and Sr[Al.sub.2][O.sub.4]:[Eu.sup.2+], codoped with rare earth ions is investigated in order to clarify the trapping mechanism of carriers in the phosphorescent process. The results have shown that the retrapping of the electron released from a trap plays a key role in the persistent phosphorescence process.

A methacrylate copolymer containing electron donor-acceptor (D-A) moieties and europium complexes (PCzOxEu) in the pendant groups is synthesized and characterized. Molecular simulations are carried out to elucidate the roles of oxadiazole moieties in improving the response time and retention time of the memory device.

The photoelectron spectra of the multiple-decker 1:1 sandwich clusters of Eu(sub n)[COT](sub n)(super -) (n=1-4) where COT=1,3,5,7-cyclooctatetraene synthesized in the gas phase and the bonding scheme, charge distribution, valence orbital energies and others were studied theoretically. The result showed that the characteristic behavior of the spectra is due to the strong ionic bonding and the charge distribution.

The unusual green photoluminescence (PL) of the N,N-dimethylformamide (DMF)/hydrochloric acid (HCL)/europium chloride solutions was investigated to clarify the emission mechanism. The result showed that the DMF/HCL pair alone can yield a green PL band under UV excitation and the emissions has features of that of excimers.