This review summarizes recent work in nanostructured insulating materials that contain optically active lanthanide ions. These materials find applications in lasers, optical amplifiers, and optical-display phosphors. This review concentrates on the synthesis and luminescence spectroscopy of lanthanide-containing nanostructured particles, films, and composites. Spectroscopic studies range from basic luminescence spectroscopy and quantum efficiency measurements to high-resolution spectroscopic studies that investigate the phonon dynamics and electron−phonon interaction as a function of particle size. This review identifies several areas for further study, including the location, distribution, or segregation of dopants in nanoparticles; the efficiency of energy transfer across interfaces; and the effects of quantum confinement or changes in phonon dynamics and electron−phonon interactions on the radiative and nonradiative relaxation rates in localized luminescent dopants.

Synthesis and luminescence of lanthanide ions in nanoscale insulating hosts

Publisher Summary This chapter describes molecular, near infrared (NIR)-emitting compounds containing Nd III , Er III , or Yb III and discrete molecular edifices containing other ions emitting in this range. It also reviews various synthetic strategies proposed for encapsulation of ions into molecular edifices and making use of macrocyclic or acyclic ligands or of d-transition metal complexes. The chapter presents novel approaches resorting to inorganic clusters, inorganic–organic hybrids, nanoparticles, or ionic liquids, and potential applications including medical imaging. The chapter illustrates the potential of organic complexes and materials for NIR-luminescent probes and highlights the difficulty in achieving reasonable emission efficiency. Some promising systems for inclusion of NIR-emitting Ln III ions are ionic liquids in which tetrakis(β-diketonates) act as the anion or doped ionogels generated by the confinement of ionic liquids within a porous silica matrix. These gels have excellent mechanical, thermal, and optical properties and feature high ionic conductivity, a key factor for electroluminescent devices.

Chapter 235 Lanthanide Near-Infrared Luminescence in Molecular Probes and Devices

Er3N@C80 exhibits sharp optical emission lines in the near-infrared attributed to fluorescence from the Er3+ ion. Here we demonstrate that high magnetic fields cause this spectrum to split, corresponding to transitions from the lowest field-split Kramers doublet of the 4I13/2 manifold to the four lowest field-split levels of the 4I15/2 manifold. The internal structure of these fullerenes can be spatially aligned with a preferred orientation under high magnetic field; the effect of alignment is to reduce the broadening associated with the isotropic spatial averaging characteristic of powder or frozen-solution spectra. Using a tunable 1.5 μm laser, we directly observe non-cage-mediated optical interactions with the Er3+ ion. This spectroscopic method provides the opportunity to map the energy level structure of the incarcerated ion and to coherently control its quantum state. These qualities suggest that rare-earth endohedral fullerenes have characteristics that could be employed as a readout pathway for fullerene-based quantum information processing. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

PL, magneto‐PL and PLE of the trimetallic nitride template fullerene Er3N@C80

PL, magneto-PL and PLE of the trimetallic nitride template fullerene Er3N@C-80

One of the nanoscale structures of carbon is the carbon nanotubes. These structures of carbon display an attractive variation of structural characteristics, and many useful forms have been synthesized and identified. Carbon nanotubes are either single-wall (SWCNT) or multiwall (MWCNT); the former attract attention due to their unique electronic, optical, and spectroscopic properties. One of the main recognized structures of single-walled nanotubes is the (5,5) single-walled tube. Endohedral metallofullerenes (Mn@Cx) were introduced as a new class of spherical fullerenes group with unique properties. Formation of endohedral metallofullerenes is thought to involve the transfer of electrons from the encapsulated metal atom(s) to the surrounding fullerene cage. Two of these molecules are Er2@C82 (1) and Sc2@C84 (2). A topological index is a mathematical invariant of a chemical graph, which shows a significant correlation with some chemical or physical properties. Topological indices have been successfully use...

Theoretical and Quantitative Structural Relationship Study of the Electrochemical Properties of [M2@Cx]@[SWCNT(5,5)-Armchair-CnH20] (M = Er and Sc, x = 82 and 84, and n = 20−300) Complexes

K. DeLapp

Papers

Spectroscopic studies of fullerenes doped with rare earth and transition metal ions