Continuous transformations of C₆₀crystals: polymorphs, polymers, and the ideal strength of fullerites

Abstract

Application of pressure is a versatile method to tailor the properties of organic semiconductors. For example, it is known that high pressure can transform C60 face-centred-cubic (FCC) crystals to polymer structures with inter-molecular bonds. Here we use first-principles calculations to describe continuous crystalline transformation paths that include the FCC and polymer structures as distinct local energy minima. In addition to analysing the atomic-scale details of polymerization, we obtain the ideal strength of FCC-C60, identify metastable C60 crystalline polymorphs, and characterize their electronic properties-all key features for the performance of C60 crystals in organic electronic devices.

High‐Efficiency Fullerene Solar Cells Enabled by a Spontaneously Formed Mesostructured CuSCN‐Nanowire Heterointerface

“…To accommodate the C 60 molecules, a 2 × 1 tetragonal supercell was used. The center‐to‐center distance of the fullerenes on the super‐cell is 13.34 and 10.94 Å, which are slightly larger than the corresponding distance in FCC‐C 60 (≈10 Å) . The band alignment was calculated at the DFT‐PBE level and corrected by the HSE06 values from the calculations on the bulk β‐CuSCN and C 60 systems.…”

Impurity-related effects in poly(3-hexylthiophene) crystals

“…41 We have applied similar methodology in the past to study a range of problems in organic electronics. [44][45][46][47] The energy cut-off for the plane-wave basis was set at 400 eV. Total-energy calculations used the Mohnkhorst-Pack scheme 48 for sampling of reciprocal space and a 2 Â 2 Â 2 grid in the case of the primitive unit cell of a pristine (impurity-free) P3HT crystal.…”

“…It is well-known that, because DFT-LDA and DFT-GGA approaches suffer from the so-called band gap problem, higher level methods, such as those View Article Online based on hybrid exchange-correlation functionals, 46,47,63,64 are needed in order to obtain more accurate positions of defect states. However, hybrid functional calculations are not feasible at present for the large P3HT supercells used in this work and will have to be performed in future studies.…”

Mechanical properties of bulk carbon nanostructures: effect of loading and temperature

“…40 First-principle calculations have been used to analyze the polymerization of C 60 fullerites under hydrostatic pressure neglecting thermal fluctuations of the atoms. 41 It was shown that even a small deformation of the spherical geometry of fullerene C 240 can evoke a shift in its electronic spectra. 42 The deformation of CNTs by surface van der Waals forces was investigated.…”