School of Physics and Astronomy

Dr John Dennis

John

Reader in Molecular Nanostructural Materials

Email: j.dennis@qmul.ac.uk
Telephone: 020 7882 3412
Room Number: G.O. Jones Building, Room 119

Profile

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Research

Research Interests:

My research interests

Dr Dennis' research centers on the synthesis, purification, and spectroscopic characterization of novel fullerene related materials. Dr Dennis conducted pioneering work in the synthesis and purification of fullerenes. During August 1990 Dr Dennis beacme the first researcher to synthesize and purify the archetypal fullerene C60 (i.e., to do both) and since then was the first to purified more fullerenes isomers than all other researchers combined; including all 9 known isomers of the third most abundant fullerene C84. To this end he has developed several counter to proper practice HPLC techniques for fullerene purification that are now commonly used in many fullerene research labs throughout the world. His present research interest include:

Temperature-dependent structural studies: through NMR spectroscopy (molecular and dynamical) and XRD (crystal). Temperature-dependant vibrational studies via FTIR and FT-Raman.

Double-walled nanotubes: developing the production and purification of double-walled carbon nanotubes (by both pulsed arc, and CVD techniques), and to exploit the durability of double-walled nanotubes to produce more reliable nano-transistors, and materials with potential applications for field emission-based flat screen displays.

Carbon peapods: By encapsulating metal element containing endohedral fullerenes within carbon nanotubes tube, the band gap tubes can be narrowed (at the points corresponding to the positions of the endohedral fullerene). Preliminary results indicate these carbon peapods can be p-type, n-type, or am-bipolar, depending on the encapsulated atom. The effects of the encapsulated atom on the electronic transport of the fullerene is investigated.

Endohedral fullerenes as contrast agents for MRI.: Gadolinium-containing endohedral fullerenes are promising species for contrast enhancement in MRI, these species have several advantages over conventional agents. The incarcerated highly toxic Gd3+ ion is severely sterically hindered to dissociation, and they are about 20 times as effective, thus are required in much smaller doses. We, in collaboration with researchers at the Institute of Chemistry at the Chinese Academy of Sciences in Beijing are currently investigating functionalisation of these species to make them water-soluble and specific tissue targeting. For example, we have recently produced bone-targeting Gd-based endohedral fullerenes.

Quantum information processing: The ESR of the nitrogen-containing endohedral fullerene iNC60 has hyperfine lines at least two orders of magnitude narrower then any other known radical, making it a possible qubit candidate for quantum computation. Having recently performed the first (and still only) isolation of iNC60, I intend to systematically investigate the potential of nitrogen- and phosphorous-containing incar-fullerenes, as dimers as novel building-block materials for electron spin-based scalable solid-state quantum computation.

Isomer-pure fullerene and endohedral fullerene-based Transistors: Recently our group has begun researching the use of fullerenes and endohedral fullerenes in semi-conductor devices, including transistors.

Before joining QMUL, Dr Dennis conducted postdoctoral research under a series of personal research fellowships from the Australian Research Council, the Japan Society for the Promotion of Science, and the Alexander von Humboldt Foundation. He gained his D.Phil. under the supervision of Prof .Harry Kroto at the University of Sussex in 1993.

Publications

  • LIU T, ABRAHAMS I, DENNIS T (2018). Structural Identification of 19 Purified Isomers of the OPV Acceptor Material bisPCBM by 13C NMR and UV-Vis Absorption Spectroscopy and High Performance Liquid Chromatography. nameOfConference



    Citations: 0
  • Shu CY, Wang CR, Zhang JF et al. (2008). Organophosphonate functionalized Gd@C-82 as a magnetic resonance imaging contrast agent. nameOfConference


    QMRO: qmroHref

    Citations: 14
  • Kanai M, Porfyrakis K, Briggs GAD et al. (2004). Purification by HPLC and the UV/Vis absorption spectra of the nitrogen-containing incar-fullerenes iNC(60), and iNC(70). nameOfConference


    QMRO: qmroHref

    Citations: 17
  • Ardavan A, Austwick M, Benjamin SC et al. (2003). Nanoscale solid-state quantum computing. nameOfConference


    QMRO: qmroHref

    Citations: 37
  • Dennis TJS, Hulman M, Kuzmany H et al. (2000). Vibrational infrared spectra of the two major isomers of [84]fullerene: C-84{D-2(IV)} and C-84(D-2d(II)}. nameOfConference


    QMRO: qmroHref

    Citations: 28
  • Dennis TJS, Kai T, Asato K et al. (1999). Isolation and characterization by 13C NMR spectroscopy of [84]fullerene minor isomers. nameOfConference

    DOI: doi

    QMRO: qmroHref

    Citations: 90
  • Dennis TJS, Kai T, Asato K et al. (1999). Isolation and Characterization by13C NMR Spectroscopy of [84]Fullerene Minor Isomers. nameOfConference


    QMRO: qmroHref

    Citations: 0
  • Allen KM, Dennis TJS, Rosseinsky MJ et al. (1998). Isomer specific intercalation chemistry: Potassium insertion into the D2 and D(2d) isomers of C84. nameOfConference


    QMRO: qmroHref

    Citations: 24
  • Dennis TJS, Shinohara H (1998). Isolation and characterisation of the two major isomers of [84]fullerene (C84). nameOfConference


    QMRO: qmroHref

    Citations: 0
  • Dennis TJS, Shinohara H (1997). Production and isolation of endohedral strontium- and barium-based mono-metallofullerenes: Sr/Ba@C-82 and Sr/Ba@C-84. nameOfConference


    QMRO: qmroHref

    Citations: 0
  • Dennis TJS (1993). Structure and Dynamics of the Fullerenes C60 and C70. nameOfConference

    DOI: doi

    QMRO: qmroHref

    Citations: 0
  • Dennis TJS, Prassides K, Roduner E et al. (1993). Rotational dynamics of solid C70 monitored by positive muon spin labels. nameOfConference


    QMRO: qmroHref

    Citations: 36
  • TAYLOR R, LANGLEY GJ, AVENT AG et al. (1993). C-13 NMR-SPECTROSCOPY OF C-76, C-78, C-84 AND MIXTURES OF C-86-C102 - ANOMALOUS CHROMATOGRAPHIC BEHAVIOR OF C-82, AND EVIDENCE FOR C70H12. nameOfConference


    QMRO: qmroHref

    Citations: 93
  • DAVID WIF, IBBERSON RM, DENNIS TJS et al. (1992). STRUCTURAL PHASE-TRANSITIONS IN THE FULLERENE C-60. nameOfConference


    QMRO: qmroHref

    Citations: 0
  • LEACH S, VERVLOET M, DESPRES A et al. (1992). ELECTRONIC-SPECTRA AND TRANSITIONS OF THE FULLERENE C-60. nameOfConference


    QMRO: qmroHref

    Citations: 367
  • Prassides K, Dennis TJS, Christides C et al. (1992). Mu@C70: Monitoring the dynamics of fullerenes from inside the cage. nameOfConference


    QMRO: qmroHref

    Citations: 39
  • DAVID WIF, IBBERSON RM, MATTHEWMAN JC et al. (1991). CRYSTAL-STRUCTURE AND BONDING OF ORDERED C60. nameOfConference


    QMRO: qmroHref

    Citations: 687
  • TAYLOR R, PARSONS JP, AVENT AG et al. (1991). DEGRADATION OF C60 BY LIGHT. nameOfConference


    QMRO: qmroHref

    Citations: 135
  • HARE JP, DENNIS TJ, KROTO HW et al. (1991). THE IR-SPECTRA OF FULLERENE-60 AND FULLERENE-70. nameOfConference


    QMRO: qmroHref

    Citations: 107