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organized structures enable the expression of completely different physical properties, which are absent in the basic material, and endow many biological materials with remarkable mechanical strength, [4] flexibility, [5] super-hydrophobicity, [6] and optical properties, [7] such as structural color. Therefore, many researchers have made great efforts to develop novel materials with unique physical properties and improved performance over conventional materials by mimicking these natural hierarchical structures. Although various biomaterials, such as DNA, [8] bacteriophages, [9] proteins, [10] carbohydrates, [11] and peptides, [12] are being researched and developed for this purpose, self-assembled peptide nanostructures [13] are most actively studied among them owing to their versatile properties. Diphenylalanine (FF) molecules, especially those derived from the dipeptide motif (-F19-F20-), which is a major contributing factor in amyloid fibril formation that causes Alzheimer's disease, are widely used to form peptide hierarchical nanostructures through a self-assembly process that induces the aggregation of FF molecules in water. [14] This molecular self-assembly approach enables us to build diverse peptide nanostructures with functional physical and chemical properties, including piezoelectricity, [15] ferroelectricity, [16] and photoluminescence, [17] as well as robust An effective strategy is developed to create peptide-based hierarchical nanostructures through the meniscus-driven self-assembly in a large area and fabricate antiferroelectric devices based on these nanostructures for the first time. The diphenylalanine hierarchical nanostructures (FF-HNs) are self-assembled by vertically pulling a substrate from a diphenylalanine (FF) solution dissolved in a miscible solvent under precisely controlled conditions. Owing to the unique structural properties of FF nanostructures, including high crystallinity and α-helix structures, FF-HNs possess a net electrical dipole moment, which can be switched in an external electric field. The mass production of antiferroelectric devices based on FF-HNs can be successfully achieved by means of this biomimetic assembly technique. The devices show an evident antiferroelectric to ferroelectric transition under dark conditions, while the ferroelectricity is found to be tunable by light. Notably, it is discovered that the modulation of antiferroelectric behaviors of FF-HNs under glutaraldehyde exposure is due to the FF molecules that are transformed into cyclophenylalanine by glutaraldehyde. This work provides a stepping stone toward the mass production of self-assembled hierarchical nanostructures based on biomolecules as well as the mass fabrication of electronic devices based on biomolecular nanostructures for practical applications.

Boosting dielectric permittivity representing electrical polarizability of dielectric materials has been considered a keystone for achieving scientific breakthroughs as well as technological advances in various multifunctional devices. Here, we demonstrate sizable enhancements of low-frequency dielectric responses in oxygen-deficient oxide ceramics through specific treatments under humid environments. Ultrahigh dielectric permittivity (~5.2 × 10 6 at 1 Hz) is achieved by hydrogenation, when Ni-substituted BaTiO 3 ceramics are exposed to high humidity. Intriguingly, thermal annealing can restore the dielectric on-state (exhibiting huge polarizability in the treated ceramics) to the initial dielectric off-state (displaying low polarizability of ~10 3 in the pristine ceramics after sintering). The conversion between these two dielectric states via the ambient environment–mediated treatments and the successive application of external stimuli allows us to realize reversible control of dielectric relaxation characteristics in oxide ceramics. Conceptually, our findings are of practical interest for applications to highly efficient dielectric-based humidity sensors.