Synthesis and high pressure studies of white luminescence host-guest complex nanocrystals based on C60 and p-But-calix[8]arene

Host-guest structured nanocrystals consisting of p-But-calix[8]arene and fullerene C₆₀ were fabricated with the facial solution deposition method. The as-prepared host-guest complex nanocrystals are well crystallized in a tetragonal structure, in which the guest C₆₀ and host p-But-calix[8]arene molecules interact with each other via the van der Waals force. The host-guest crystal has a wider band gap compared to that of C₆₀ crystals. The luminescence range of the host-guest structured nanocrystals was widely extended, and its photoluminescence (PL) intensity was highly enhanced by one order of magnitude. High pressure studies on such host-guest nanocrystals were carried out using the diamond anvil cell technique with the associated spectroscopic measurements. Raman and PL spectra show a phase transition occurred on the samples owing to the deformation of fullerene molecules. A PL behavior change was also observed synchronously with the phase transition. The host-guest structure strongly influences the structure and optical behaviors of C₆₀ under pressure.

Revealing unusual rigid diamond net analogues in superhard titanium carbides

We found three diamond net analogues in titanium carbides firstly, including hard TiC₂, superhard TiC₃ and TiC₄. Their hardness mainly originates from the strong covalent interactions of diamond-like C-layers.

Photoluminescence changes of C70 nano/submicro-crystals induced by high pressure and high temperature

Hollow C₇₀ nano/submicro-crystals with a fcc lattice structure were treated under various high pressure and high temperature conditions. The energy band structure was visibly changed by the high pressure and high temperature treatment, and the luminescence of the treated C₇₀ nano/submicro-crystals were tuned from the visible to the near infrared range. In-situ high pressure experiments at room temperature indicate that pressure plays a key role in the tuning of the band gap and PL properties in C₇₀ nanocrystals, and temperature plays an important role in the formation of stable intermolecular bonds and thus to define the final red-shift of the PL peaks. The polymeric phases of C₇₀ nanocrystals treated at high pressure and high temperature were identified from their Raman spectra, which showed a change from monomers to a dimer-rich phase and finally to a phase containing larger, disordered C₇₀ oligomers.

Graphene mediated self-assembly of fullerene nanorods

A simple procedure for solution-based self-assembly of C₆₀ fullerene nanorods on graphene substrates is presented.