Graphullerite: A Thermally Conductive and Remarkably Ductile Allotrope of Polymerized Carbon.

The understanding of the fundamental relationships between chemical bonding and material properties, especially for carbon allotropes with diverse orbital hybridizations, is significant from both scientific and applicative standpoints. Here, we elucidate the influence of the intermolecular covalent bond configuration on the mechanical and thermal properties of polymerized fullerenes by performing systematic atomistic simulations on graphullerite, a newly synthesized crystalline polymer of C with a hexagonal lattice similar to that of graphene. Specifically, we show that the polymerization of C molecules into two-dimensional sheets (and three-dimensional layered structures) offers tunable control over their mechanical and thermal properties via the replacement of weak intermolecular van der Waals interactions between the fullerene molecules with strong sp covalent bonds.

Thermally Conductive Self-Healing Nanoporous Materials Based on Hydrogen-Bonded Organic Frameworks.

Hydrogen-bonded organic frameworks (HOFs) are a class of nanoporous crystalline materials formed by the assembly of organic building blocks that are held together by a network of hydrogen-bonding interactions. Herein, we show that the dynamic and responsive nature of these hydrogen-bonding interactions endows HOFs with a host of unique physical properties that combine ultraflexibility, high thermal conductivities, and the ability to "self-heal". Our systematic atomistic simulations reveal that their unique mechanical properties arise from the ability of the hydrogen-bond arrays to absorb and dissipate energy during deformation.

Supramolecular Interactions Lead to Remarkably High Thermal Conductivities in Interpenetrated Two-Dimensional Porous Crystals.

The design of innovative porous crystals with high porosities and large surface areas has garnered a great deal of attention over the past few decades due to their remarkable potential for a variety of applications. However, heat dissipation is key to realizing their potential. We use systematic atomistic simulations to reveal that interpenetrated porous crystals formed from two-dimensional (2D) frameworks possess remarkable thermal conductivities at high porosities in comparison to their three-dimensional (3D) single framework and interpenetrated 3D framework counterparts.

Highly Negative Poisson's Ratio in Thermally Conductive Covalent Organic Frameworks.

The prospect of combining two-dimensional materials in vertical stacks has created a new paradigm for materials scientists and engineers. Herein, we show that stacks of two-dimensional covalent organic frameworks are endowed with a host of unique physical properties that combine low densities, high thermal conductivities, and highly negative Poisson's ratios. Our systematic atomistic simulations demonstrate that the tunable mechanical and thermal properties arise from their singular layered architecture comprising strongly bonded light atoms and periodic laminar pores.

Uniquely anisotropic mechanical and thermal responses of hybrid organic-inorganic perovskites under uniaxial strain.

The complete understanding of the mechanical and thermal responses to strain in hybrid organic-inorganic perovskites holds great potential for their proper functionalities in a range of applications, such as in photovoltaics, thermoelectrics, and flexible electronics. In this work, we conduct systematic atomistic simulations on methyl ammonium lead iodide, which is the prototypical hybrid inorganic-organic perovskite, to investigate the changes in their mechanical and thermal transport responses under uniaxial strain. We find that the mechanical response and the deformation mechanisms are highly dependent on the direction of the applied uniaxial strain with a characteristic ductile- or brittle-like failure accompanying uniaxial tension.