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A gyroid crystal possesses a peculiar structural feature that can be conceptualized as a triply periodic surface with a constant mean curvature of zero. The exotic optical properties such as the photonic bandgap and optical chirality can emerge from this three-dimensional (3D) morphological feature. As such, gyroid crystals have been considered as the promising structures for photonic crystals and optical metamaterials. To date, several methods have been proposed to materialize gyroid crystals, including 3D printing, layer-by-layer stacking, two-photon lithography, interference lithography, and self-assembly. Furthermore, the discovery of Weyl points in gyroid crystals has further stimulated these advancements. Among such methods, the self-assembly of block copolymers (BCPs) is unique, because this soft approach can provide an easy-to-craft gyroid, especially at the nanoscale. The unit-cell scale of a gyroid ranging within 30–300 nm can be effectively addressed by BCP self-assembly, whereas other methods would be challenging to achieve this size range. Therefore, a BCP gyroid has provided a material platform for metamaterials and photonic crystals functioning at optical frequencies. Currently, BCP gyroid nanophotonics is ready to take the next step toward topological photonics beyond the conventional photonic crystals and metamaterials. In particular, the intrinsic lattice transformations occurring during the self-assembly of BCP into a gyroid crystal could promise a compelling advantage for advancing Weyl photonics in the optical regime. Lattice transformations are routinely considered as limitations, but in this review, we argue that it is time to widen the scope of the lattice transformations for the future generation of nanophotonics. Thus, our review provides a comprehensive understanding of the gyroid crystal and its lattice transformations, the relevant optical properties, and the recent progress in BCP gyroid self-assembly.

High‐performance chiroptical synaptic phototransistors are successfully demonstrated using heterojunctions composed of a self‐assembled nanohelix of a π‐conjugated molecule and a metal oxide semiconductor. To impart strong chiroptical activity to the device, a diketopyrrolopyrrole‐based π‐conjugated molecule decorated with chiral glutamic acid is newly synthesized; this molecule is capable of supramolecular self‐assembly through noncovalent intermolecular interactions. In particular, nanohelix formed by intertwinded fibers with strong and stable chiroptical activity in a solid‐film state are obtained through hydrogen‐bonding‐driven, gelation‐assisted self‐assembly. Phototransistors based on interfacial charge transfer at the heterojunction from the chiroptical nanohelix to the metal oxide semiconductor show excellent chiroptical detection with a high photocurrent dissymmetry factor of 1.97 and a high photoresponsivity of 218 A W−1. The chiroptical phototransistor demonstrates photonic synapse‐like, time‐dependent photocurrent generation, along with persistent photoconductivity, which is attributed to the interfacial charge trapping. Through the advantage of synaptic functionality, a trained convolutional neural network successfully recognizes noise‐reduced circularly polarized images of handwritten alphabetic characters with better than 89.7% accuracy. [ABSTRACT FROM AUTHOR]

In this work, we present a theoretical framework that unifies polymer field theory and density functional theory in order to efficiently predict ordered nanostructure formation of systems having considerable complexity in terms of molecular structures and interactions. We validate our approach by comparing its predictions with previous simulation results for model systems. We illustrate the flexibility of our approach by applying it to hybrid systems composed of block copolymers and ligand coated nanoparticles. We expect that our approach will enable the treatment of multicomponent self-assembly with a level of molecular complexity that approaches experimental systems. [ABSTRACT FROM AUTHOR]

The hierarchically porous carbon fabrics with controlled conductivity and hydrophilicity have been fabricated by dual templating method of soft templates nested on hard templates. A non‐woven fabric coated with a solution of F127/resol has been carbonized for the synthesis of both macro‐porous structures of 10–15 µm in diameter having meso‐porous carbon structures of 4–6 nm, respectively. After carbonization treatment, not only conductivity is significantly improved, the hierarchically porous carbon also shows superhydrophilicity or water‐absorbing nature due to mild hydrophilic material and its dual scale roughness. The porous carbon becomes conductive with resistivity widely tuned from 5.4 × 103 Ωm to 3.1 × 10−3 Ωm by controlling the carbonization temperature. As the increased wettability for organic liquids could lead organic molecules deep into carbonized fabrics, the sensitivity of hierarchically porous carbon fabrics benefits the detection for methanol(CH3OH) or hydrogen peroxide (H2O2). This new design concept of hierarchically porous structures having the multi‐functionality of high wettability and conductivity can be highly effective for electroanalytical sensors. [ABSTRACT FROM AUTHOR]

An optically controlled energy‐harvesting smart window that incorporates a semitransparent solar cell with a photo­sensitive liquid crystal (LC) layer is demonstrated. The LC layer can switch between a transparent (day mode) and an opaque (night mode) state depending upon the incident solar radiation. Combined with a photovoltaic cell, this window provides a template for future smart window systems. [ABSTRACT FROM AUTHOR]

“Bottom up” type nanoparticle (NP) self-assemblyis expected to provide facile routes to nanostructured materials forvarious, for example, energy related, applications. Despite progressin simulations and theories, structure prediction of self-assembledmaterials beyond simple model systems remains challenging. Here weutilize a field theory approach for predicting nanostructure of complexand multicomponent hybrid systems with multiple types of short- andlong-range interactions. We propose design criteria for controllinga range of NP based nanomaterial structures. In good agreement withrecent experiments, the theory predicts that ABC triblock terpolymerdirected assemblies with ligand-stabilized NPs can lead to chiralNP network structures. Furthermore, we predict that long-range Coulombinteractions between NPs leading to simple NP lattices, when appliedto NP/block copolymer (BCP) assemblies, induce NP superlattice formationwithin the phase separated BCP nanostructure, a strategy not yet realizedexperimentally. We expect such superlattices to be of increasing interestto communities involved in research on, for example, energy generationand storage, metamaterials, as well as microelectronics and informationstorage. [ABSTRACT FROM AUTHOR]