Nikos Tagmatarchis

Amino acid functionalisation of water soluble carbon nanotubes

High solubility of SWNTs and MWNTs in water is obtained by organic functionalisation; derivatisation with N-protected glycine is also easily achieved.

Functionalised single wall carbon nanotubes/polypyrrole composites for the preparation of amperometric glucose biosensors

Ferrocenyl-functionalised SWNTs are coupled to glucose oxidase within an amphiphilic polypyrrole matrix for the amperometric catalytic detection of glucose.

Linear and Nonlinear Optical Properties of (60)Fullerene Derivatives

Using a wide variety of quantum-chemical methods we have analyzed in detail the linear and non-linear optical properties of [60]fullerene-chromophore dyads of different electron-donor character. The dyads are composed of [60]fullerene covalently linked with 2,1,3-benzothiadiazole and carbazole derivatives. Linear scaling calculations of molecular (hyper)polarizabilities were performed using wave function theory as well as density functional theory (DFT). Within the former approach, we used both semiempirical (PM3) and ab initio (Hartree-Fock and second-order Møller-Plesset perturbation theory) methods. Within the latter approach only the recently proposed long-range (LRC) schemes successfully avoid a large overshoot in the value obtained for the first hyperpolarizability (β). Calculations on model fullerene derivatives establish a connection between this overshoot and the electron-donating capability of the substituent. Substitution of 2,1,3-benzothiadiazole by the triphenylamine group significantly increases the electronic first and second hyperpolarizabilities as well as the two-photon absorption cross section. For [60]fullerene-chromophore dyads we have, additionally, observed that the double harmonic vibrational contribution to the static beta is much larger than its electronic counterpart. The same is true for the dc-Pockels β as compared to the static electronic value, although the vibrational term is reduced in magnitude; for the intensity-dependent refractive index the vibrational and electronic terms are comparable. A nuclear relaxation treatment of vibrational anharmonicity for a model fulleropyrrolidine molecule yields a first-order contribution that is substantially more important than the double harmonic term for the static β.

Multiwalled carbon nanotubes in donor–acceptor nanohybrids—towards long-lived electron transfer products

Novel multiwalled carbon nanotube/metalloporphyrin nanohybrids are devised and probed as versatile donor-acceptor hybrids.

Nanosized inorganic/organic composites for solar energy conversion

Structural design of donor (i.e., size-quantized CdTe nanoparticle)–acceptor (i.e., water-soluble C60 derivative) systems led to promising layer-by-layer assembled photovoltaic thin films with photon-to-current conversion efficiencies of 5.4%.

Donor-acceptor nanoensembles of soluble carbon nanotubes{

Donor-acceptor nanoensembles, prepared via electrostatic interactions of single wall carbon nanotubes and porphyrin salts, give rise to photoinduced intra-complex charge separation that lasts tens of microseconds.

Chemical Functionalization of Exfoliated Graphene

Graphene is turning out to be the material that will effectively kick-start a new era for nanotechnology. The impressive properties of this atom-thick carbon layer are taking shape and form with early reports of successful applications based on it. The turning point for this material will be its low-cost mass production. In this report a chemists perspective on the production methods for graphene and the subsequent functionalization processes is discussed.

Carbon-based materials: From fullerene nanostructures to functionalized carbon nanotubes

Self-assembly in morphological organization of various fullerene derivatives affords different supramolecular architectures. Nanospheres, tubules, and bundles of nanorods are formed depending on the nature of the organic group in the fullerene unit. The current work highlights an efficient method to fabricate almost perfect and uniformly shaped nanocrystals in a novel connection between spherical fullerene-based materials and fibrous nanotubes. In a parallel research line, carbon nanotubes (CNTs) have been functionalized using 1,3-dipolar cycloaddition of azomethine ylides. The organically functionalized CNTs, having improved solubility and potential for applications, are characterized by standard analytical methods as well as microscopy techniques.

Solvent-free microwave-assisted Bingel reaction in carbon nanohorns

In this paper we exploit the benefits of microwave-assisted functionalization of carbon nanohorns (CNHs). Using Bingel reaction conditions we have successfully incorporated malonyl moieties in CNHs. The resulting hybrid materials were characterized by diverse and complementary analytical techniques, including Raman, UV-Vis and photoluminescence spectroscopy, transmission electron microscopy, thermogravimetric analysis, while electrochemistry was employed to determine possible variations in the energy levels when photoactive units were grafted onto the skeleton of CNHs.

Azafullerenes encapsulated within single-walled carbon nanotubes.

Methods of insertion of azafullerenes in single-walled carbon nanotubes (SWNTs) at different temperatures were investigated, while the effects of the conditions applied on the structure of azafullerene-based peapods, namely, C59N@SWNTs, were explored. Morphological characteristics of C59N@SWNTs were assessed and evaluated by means of high-resolution transmission electron microscopy (HR-TEM). Pathways and chemical reactions that occur upon encapsulation of C59N within SWNTs were evaluated. Monomeric azafullerenyl radical C59N. as inserted into SWNTs at high temperature, from purified (C59N)2 in the gas phase, can undergo a variety of different transformations forming dimers, oligomers or existing in its monomeric form inside SWNTs due to the stabilization effect by nanotube side walls. However, under milder conditions, that is, at lower temperature, bisazafullerene (C59N)2 can be inserted into SWNTs in its pristine dimeric form.