Npg Asia Materials最新文献

A block copolymer (BCP) with specific monomer structures of fluoroacrylate polymers was designed by exploiting the inorganic superhydrophobicity and low glass transition temperature of polydimethylsiloxane (PDMS). With the use of a fluorine-containing block providing a surface tension as low as that of PDMS (19.9 < (gamma) < 21.5 mN/m), PDMS-b-poly(2,2,3,3,3-pentafluoropropyl acrylate) (PDMS-b-PPeFPA) copolymer was synthesized to create a volume-symmetric lamellar structure. The compositional randomness of the BCP chains adsorbed onto the substrates provided well-balanced interfacial interactions toward the overlaid PDMS-b-PPeFPA ((gamma)_PDMS-ads ≈ (gamma)_PPeFPA-ads). Under this symmetric confinement with simultaneous dual neutral interfaces, lamellar microdomains with a sub-10 nm half-pitch feature size were successfully oriented perpendicular to the interfaces at room temperature. We showed the response of the BCP films to a lateral electric field, demonstrating that the perpendicular lamellae were adaptively aligned along the electric vector within a short treatment period. Furthermore, the PDMS-b-PPeFPA system exhibited a remarkable etch contrast for O₂ reactive ion etching, yielding unidirectionally aligned air–inorganic nanoarrays emanating from the perpendicular lamellae between the electrodes. This study reports a system engineering approach for conceiving highly immiscible, silicon- and fluorine-containing BCP whose components exhibit identical surface tensions ((gamma)_PDMS ≈ (gamma)_PPeFPA) and for generating perpendicularly oriented lamellar microdomains due to substrate neutrality.

Oxide-based thermoelectric materials that show a high figure of merit are promising because of their good chemical and thermal stabilities and their relative harmlessness compared with chalcogenide-based state-of-the-art thermoelectric materials. Although several high-ZT thermoelectric oxides (ZT > 1) have been reported thus far, their reliability levels are low due to the lack of careful observations of their stabilities at elevated temperatures. Herein, we review the epitaxial film growth and thermoelectric properties of representative p-type layered cobalt oxides: Na_3/4CoO₂, Ca_1/3CoO₂, Sr_1/3CoO₂, Ba_1/3CoO₂, and Ca₃Co₄O₉. Among these specimens, Ba_1/3CoO₂ and Ca₃Co₄O₉ are stable in air at elevated temperatures (~600 °C). The ZT of Ba_1/3CoO₂ reaches ~ 0.55 at 600 °C in air, which is reliable and the highest among thermoelectric oxides. Moreover, this value is comparable to those of p-type PbTe and p-type SiGe.

Shape-memory polymers (SMPs) are smart materials that have gained significant attention in recent years owing to their widespread application in smart structures and devices. Digital light processing (DLP), a vat-photopolymerization-based technique, is a significantly faster technology for printing a complete layer in a single step. The current study reports a facile and fast method for the 3D printing of SMP-based smart structures using a DLP 3D printer and a customized resin. A liquid crystal (LC, RM257) was combined with the resin to introduce shape-memory properties. The combination of LCs in photocurable resin provides the opportunity to directly 3D-print thermoresponsive structures, avoiding the complexity of SMP resin preparation. The structures were printed with different geometries, and the shape-memory response was measured. Lattice structures were fabricated and programmed to obtain tunable mechanical properties. Furthermore, the strain-sensing response was measured to demonstrate the utility of these lattice structures as smart patches for joint-movement sensing. The SMPs can be prepared conveniently and can potentially be used for various applications, such as smart tools, toys, and meta-material sensors.

Ionogels are crosslinked networks—typically polymeric networks—swollen with ionic liquids. The unique properties of ionogels, such as nonvolatility, ionic conductivity, nonflammability, and high thermal and electrochemical stability, make them promising for a variety of applications. Examples include sensors, adhesives, energy storage devices, and ionotronics. While many ionogels require complex syntheses and suffer from poor mechanical properties, simpler strategies are emerging to produce tough ionogels, thereby improving the durability, enabling 3D printing, and broadening the application space of ionogels. This perspective highlights promising applications and future opportunities of ionogels.

Osmotic energy generation with reverse electrodialysis through membranes provides a worldwide free energy resource. Photo-driven proton transport in photosynthesis supplies basal energy for plants and living organisms on the planet. Here, we utilized aramid nanofiber (ANF) semiconductor-based membranes to enable light-driven proton transport for osmotic energy generation. Under unilateral illumination, the light-driven proton transport system converted light energy into electrical energy and showed wavelength- and intensity-dependent transmembrane potentials and currents. Interestingly, the synergistic effects of simultaneous illumination and pressure provided a five-fold increase in the voltage and a three-fold increase in the current relative to pressure alone. Density functional theory calculations and spectroscopic measurements demonstrated that the ANF and photoinduced electrons enabled proton transport during illumination and generated a transmembrane potential and current. The light-driven proton transport system supports the development of devices with flexible and stable ANF membranes.

Transparent conductors with electromagnetic shielding capabilities (TC-EMS) are rare, despite their significant potential for creating new functionalities in energy and military applications. Here, we investigate the potential of La-doped BaSnO₃ (BLSO) for TC-EMS since its epitaxial film has been known to have low sheet resistance and high visible transmittance. However, films grown on industrially practical Al₂O₃ substrates exhibit a sheet resistance three orders of magnitude higher than that of reported films grown on perovskites. Here, this problem is addressed by templating a BaZrO₃/MgO bilayer on (0001)-oriented Al₂O₃ substrates to yield single-crystalline BLSO epitaxial films. The absence of grain boundaries in the epitaxial films minimizes the electron scattering. Due to the affirmative correlation between the conductivity and crystallinity, 5% La doping is optimal among the 5−20% La concentrations studied; these 480-nm-thick films have the highest crystallinity and the lowest sheet resistances of ~28 Ω ▯⁻¹; this value is similar to that of single-crystalline levels. Due to their very high transmittances (~82% in a range 400−1000 nm) and effective X-band electromagnetic shielding (~18.6 dB), the BLSO epitaxial films grown on Al₂O₃ have great potential to be used for inexpensive TC-EMS applications.

Controlling molecular spin quantum bits optically offers the potential to effectively reduce decoherence and raise the working temperature of quantum computers. Here, exchange interactions and spin dynamics, as mediated by an optically driven triplet state, are calculated for a molecule that consists of a pair of radicals and represents a potential quantum-circuit building block. Consistent with the previous experimental observation of spin coherence induced by the triplet state, our work demonstrates an optically driven quantum gate operation scheme in a molecule. A technological blueprint combining a two-dimensional molecular network and programmable nanophotonics, both of which are sufficiently developed, is proposed. We thus realize computational exploration of chemical databases to identify suitable candidates for molecular spin quantum bits and couplers to be hybridized with nanophotonic devices. The work presented here is proposed to realize a new approach for exploring molecular excited states and click chemistry, toward advancing molecular quantum technology.