arXiv subjects

Wookjin Jung

Publications and source records attributed to Wookjin Jung.

3 recordsLinked to original sources

arXiv2026

Chiropiezoelectric Energy Harvesting from Lattice-Handedness-Controlled Selenium Nanowires

The growth of wearable electronics, soft robotics, and Internet-of-Things systems has intensified the demand for inorganic piezoelectric materials that harvest weak biomechanical energy. Advances through composition optimization, defect engineering, strain engineering, and orientation control have improved existing electromechanical responses, but have not introduced a new mechanism for enhancing piezoelectricity. Here we propose atomic chirality engineering as a design principle for inorganic piezoelectric nanomaterials. Unlike conventional strategies that modify composition or morphology, atomic chirality alters the handedness of the crystal lattice itself, adding a degree of freedom for controlling dipole alignment, electromechanical coupling, and potentially spin-dependent transport. Using atomically chiral trigonal selenium nanowires as a model system, we show that crystal handedness alone changes piezoelectric performance at identical chemical composition. Piezoresponse force microscopy resolved a consistent enantiomeric difference, with right-handed D-Se nanowires reaching a higher effective piezoelectric coefficient than their left-handed counterparts, and flexible nanogenerators and self-powered acoustic sensors built from the two enantiomers produced distinct outputs under identical deformation. This work establishes atomic chirality as a distinct route for designing piezoelectric materials, one that may extend across non-centrosymmetric inorganic semiconductors for sustainable energy harvesting and wearable sensing.

cond-mat.mtrl-sci↗

arXiv2026

Chiroptical Ternary Entropy Harvesting from Self-Assembled Block Copolymer Nanopatterns

Nanoscale fabrication inevitably produces local stochasticity that is commonly treated as a defect, but can instead be harnessed as a material resource for information security. Here we report a chiroptical platform for ternary entropy harvesting based on stochastic Au nanopatterns formed by block copolymer self-assembly. By transducing fabrication-induced stochastic microstates into handedness-dependent optical responses through chiroptical mapping, our platform enables native ternary digitization rather than conventional binary encoding, allowing physically harvested ternary random sequences to be used for key generation. This raises the information density to log2(3) = 1.585 bits per trit, approximately 58.5% higher than the binary limit, enabling more entropy to be harvested from a limited physical footprint. The harvested outputs exhibit near-balanced symbol populations, negligible spatial and inter-sample correlations, Shannon entropy approaching the ternary ideal, and resistance to statistical and machine-learning-based prediction. These results establish self-assembled chiroptical nanostructures as a scalable platform for cryptographic key generation, secure edge devices, and distributed Internet-of-Things platforms.

cond-mat.mtrl-sci↗

arXiv2025

Translating Chirality into Multidirectional Motion through Broadband Chiroptical MXenes

The integration of chirality into functional materials enables control of light-matter interactions beyond binary illumination (on/off). Conventional photoactuators rely on binary modulation, limiting them to unidirectional motion. In contrast, we introduce a ternary optical logic paradigm where actuation direction is encoded by the handedness of circularly polarized light (CPL). Here, we establish a chiral Ti$_{3}$C$_{2}$T$_{x}$ MXene platform bridging molecular chirality and mechanical actuation. Phenylalanine enantiomers are covalently anchored onto MXene nanoflakes via chiral nanopainting. The 2D confinement forces ligands into vertically aligned supramolecular networks. Interlayer-spacing analysis and simulations corroborate that such supramolecular networks unlock exceptionally broadband circular dichroism from the ultraviolet to the near-infrared. This supramolecular chirality synergizes with MXene's plasmonic properties to drive handedness-dependent photothermal conversion, with a 30\% differential temperature rise between matched and mismatched CPL. Embedding this chiral MXene into thermoresponsive hydrogels realizes, to the best of our knowledge, the first CPL-driven soft actuator that implements LCP/RCP/off as a ternary input to program multidirectional deformation based on a photothermal mechanism. This molecular-to-macroscopic translation demonstrates a new paradigm for chirality-encoded soft robotics and adaptive photonics.

cond-mat.mtrl-sci↗