C60 field effect transistor with electrodes modified by La@C82

Stability computations for isomers of La@C(n) (n = 72, 74, 76)

Density-functional theory calculations are presented for low-energy La@C₇₂, La@C₇₄ and La@C₇₆ isomers with IPR (isolated pentagon rule) and non-IPR cages. The relative isomeric production yields at high temperatures are evaluated using the calculated terms, and the relationships to observations are discussed.

DFT calculations on the structural stability and infrared spectroscopy of endohedral metallofullerenes

Endohedral metallofullerenes M@C(24) (M = Li(0/+), Na(0/+), K(0/+), Be(0/2+), Mg(0/2+) and Ca(0/2+)) with different spin configurations have been systematically investigated using the hybrid DFT-B3PW91 functional in conjunction with 6-31 G(d) basis sets. Our theoretical studies show that Li@C(24), Be@C(24), Be(2+)@C(24), and Mg(2+)@C(24) are energetically favorable. In these endohedral metallofullerenes, only the encapsulated Be and Ca atoms can donate the electrons to the cage. With exception of Be(2+)@C(24), the energy gaps of other charged compounds are larger than that of corresponding neutral compounds. We also find that some endohedral metallofullerenes have high energy gaps, but they are unlikely to show high thermodynamic stability. Additionally, the vibrational frequencies and active infrared intensities are also used as evidence to identify these endohedral metallofullerenes.

Electrical Conductance Tuning and Bistable Switching in Poly(N-vinylcarbazole)-Carbon Nanotube Composite Films

By varying the carbon nanotube (CNT) content in poly(N-vinylcarbazole) (PVK) composite thin films, the electrical conductance behavior of an indium-tin oxide/PVK-CNT/aluminum (ITO/PVK-CNT/Al) sandwich structure can be tuned in a controlled manner. Distinctly different electrical conductance behaviors, such as (i) insulator behavior, (ii) bistable electrical conductance switching effects (write-once read-many-times (WORM) memory effect and rewritable memory effect), and (iii) conductor behavior, are discernible from the current density-voltage characteristics of the composite films. The turn-on voltage of the two bistable conductance switching devices decreases and the ON/OFF state current ratio of the WORM device increases with the increase in CNT content of the composite film. Both the WORM and rewritable devices are stable under a constant voltage stress or a continuous pulse voltage stress, with an ON/OFF state current ratio in excess of 10(3). The conductance switching effects of the composite films have been attributed to electron trapping in the CNTs of the electron-donating/hole-transporting PVK matrix.

Effects of doping on electronic structure and correlations in carbon peapods

Sc@C(82) peapods, which form encapsulated spin-1/2 antiferromagnetic chains under doping with electrons or holes are investigated using hybrid density functional theory. The narrow fullerene bands become shifted relative to nanotube bands resulting in charge transfer and conducting channels along both the fullerene chain and the nanotube. This is accompanied by a reduction in the magnetic moments on the fullerenes, consistent with a 1D Hubbard-Anderson model description.

Controlled surface ordering of endohedral fullerenes with a SrTiO(3) template

The ability to select the way in which atoms and molecules self-organize on a surface is important for synthesizing nanometre scale devices. Here we show how endohedral fullerenes (Er(3)N@C(80)) can be assembled into four distinctive arrangements on a strontium titanate surface template. Each template pattern correlates to a particular reconstruction on n-doped SrTiO(3)(001), made in whole or in part by self-assembled arrays of non-stoichiometric oxide nanostructures. Close-packed assemblies of Er(3)N@C(80) molecules are formed, as well as one-dimensional chains and two-dimensional grids. This method of template-assisted molecular ordering provides a new platform for the development of experimental schemes of classical and quantum information processing at the molecular level.

Unexpected Chemical and Electrochemical Properties of M3N@C80 (M = Sc, Y, Er)

The unexpected isomerization of N-ethyl [6,6]-pyrrolidino-Y3N@C80 to the [5,6] regioisomer is reported, as well as the synthesis, characterization, and electrochemical analysis of Er3N@C80 derivatives. A complete electrochemical study of the M3N@C80 species (M = Sc, Y, Er) and their derivatives is presented. We introduce electrochemistry as a new tool in the characterization of the [5,6] and [6,6] regioisomers of trimetallic nitride endohedral metallofullerenes.