Entropy-Driven Formation of the Gyroid Cubic Phase

Ellison, Laurence; Michel, D.; Barmes, F.; Cleaver, Douglas J.

doi:10.1103/physrevlett.97.237801

Cited by 52 publications

(41 citation statements)

References 18 publications

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“…In addition to this nanosegregation mechanism, the average molecular shape should be a tapered one, deviating slightly from a rod shape, which is, however, not so easily predicted from the actual chemical structure. By computer simulation, it was shown that tapered or pear‐shaped particles, interacting with each other through purely repulsive interactions, can self‐assemble to form a 3D network structure with Ia 3 d symmetry 25. For the semiclassical rod‐shaped molecules (which, strictly speaking, should be referred to as nearly rod‐shaped), introduction of chirality (as in 6 ),11c,14 CC double bonds,11h,22c and branching in the aliphatic tails(s)10h have also been examined.…”

Section: Molecular Structuresmentioning

confidence: 99%

Recent Progress in the Synthesis and Structural Clarification of Thermotropic Cubic Phases

Kutsumizu

2012

Israel Journal of Chemistry

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This review article focuses on recent advances and challenges in the field of thermotropic cubic phases of the bicontinuous type (Cub bi ) formed by low molecular mass molecules. In the Cub bi phases, the constituent molecules self-organize into 3D network structures, although local molecular diffusional motions are preserved to some extent. This review illustrates which types of molecules form such structures, and summarizes the latest developments in structural characterization. Moreover, their phase behaviors, and analogies and differences in comparison with other related systems such as lyotropic liquid crystals and block copolymers are discussed. Finally, potential applications utilizing the dynamically ordered 3D network structures are presented.

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Section: Molecular Structuresmentioning

confidence: 99%

Recent Progress in the Synthesis and Structural Clarification of Thermotropic Cubic Phases

Kutsumizu

2012

Israel Journal of Chemistry

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“…21 In principle, such systems should yield improved phase connectivity when compared with the basic percolation pathways offered by random blends. The observation that such phases can freely self-assemble from systems as simple as appropriately-shaped hard particles 22 indicates that there is no length-scale limitation on the periodicities of these phases. We speculate, therefore, that there are no fundamental materials problems that would prevent realisation of a hybrid solar cell device based on a gyroid morphology.…”

Section: Introductionmentioning

confidence: 99%

Bicontinuous minimal surface nanostructures for polymer blend solar cells

Kimber

Walker

Schröder‐Turk

et al. 2010

Phys. Chem. Chem. Phys.

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This paper presents the first examination of the potential for bicontinuous structures such as the gyroid structure to produce high efficiency solar cells based on conjugated polymers. The solar cell characteristics are predicted by a simulation model that shows how the morphology influences device performance through integration of all the processes occurring in organic photocells in a specified morphology. In bicontinuous phases, the surface defining the interface between the electron and hole transporting phases divides the volume into two disjoint subvolumes. Exciton loss is reduced because the interface at which charge separation occurs permeates the device so excitons have only a short distance to reach the interface. As each of the component phases is connected, charges will be able to reach the electrodes more easily. In simulations of the current-voltage characteristics of organic cells with gyroid, disordered blend and vertical rod (rods normal to the electrodes) morphologies, we find that gyroids have a lower than anticipated performance advantage over disordered blends, and that vertical rods are superior. These results are explored thoroughly, with geminate recombination, i.e. recombination of charges originating from the same exciton, identified as the primary source of loss. Thus, if an appropriate materials choice could reduce geminate recombination, gyroids show great promise for future research and applications.

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“…It is our hypothesis that explicit anisotropy measures such as the Minkowski tensors will turn out similarly useful for the identification of phase transitions in fluids and other particulate systems, while being more generic and robust in their definition than measures based on neighborhoods. Explicit anisotropy measures may also be more easily generalized to aspherical particles, relevant to liquid crystalline phases [18,19,20].…”

Section: Introductionmentioning

confidence: 99%

Local anisotropy of fluids using Minkowski tensors

Kapfer¹,

Mickel²,

Schaller³

et al. 2010

J. Stat. Mech.

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Statistics of the free volume available to individual particles have previously been studied for simple and complex fluids, granular matter, amorphous solids, and structural glasses. Minkowski tensors provide a set of shape measures that are based on strong mathematical theorems and easily computed for polygonal and polyhedral bodies such as free volume cells (Voronoi cells). They characterize the local structure beyond the two-point correlation function and are suitable to define indices 0 ≤ β a,b ν ≤ 1 of local anisotropy. Here, we analyze the statistics of Minkowski tensors for configurations of simple liquid models, including the ideal gas (Poisson point process), the hard disks and hard spheres ensemble, and the Lennard-Jones fluid. We show that Minkowski tensors provide a robust characterization of local anisotropy, which ranges from β a,b ν ≈ 0.3 for vapor phases to β a,b ν → 1 for ordered solids. We find that for fluids, local anisotropy decreases monotonously with increasing free volume and randomness of particle positions. Furthermore, the local anisotropy indices β a,b ν are sensitive to structural transitions in these simple fluids, as has been previously shown in granular systems for the transition from loose to jammed bead packs.

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Entropy-Driven Formation of the Gyroid Cubic Phase

Cited by 52 publications

References 18 publications

Recent Progress in the Synthesis and Structural Clarification of Thermotropic Cubic Phases

Recent Progress in the Synthesis and Structural Clarification of Thermotropic Cubic Phases

Bicontinuous minimal surface nanostructures for polymer blend solar cells

Local anisotropy of fluids using Minkowski tensors

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