Molecular Engineering of Coordination Ligand for Multifunctional Sol-Gel Oxides.

Here a ligand exchange strategy for synthesizing sol-gel oxides is demonstrated to achieve multifunctionality including direct photolithography, high dielectric strength, and high charge carrier mobility, which is challenging to obtain in such oxides. For this purpose, a series of bidentate ligands with azide termini and ethylene-glycol bridges is synthesized, and these ligands are universally applicable to the synthesis of a variety of dielectric and semiconductor oxides. Optimized photolithography conditions yield a high-quality ZrO dielectric film with a high dielectric constant and strength of ≈18 and ≈7 MV cm, respectively.

Hydrophilic Photocrosslinkers as a Universal Solution to Endow Water Affinity to a Polymer Photocatalyst for an Enhanced Hydrogen Evolution Rate.

A universal approach for enhancing water affinity in polymer photocatalysts by covalently attaching hydrophilic photocrosslinkers to polymer chains is presented. A series of bisdiazirine photocrosslinkers, each comprising bisdiazirine photophores linked by various aliphatic (CL-R) or ethylene glycol-based bridge chains (CL-TEG), is designed to prevent crosslinked polymer photocatalysts from degradation through a safe and efficient photocrosslinking reaction at a wavelength of 365 nm. When employing the hydrophilic CL-TEG as a photocrosslinker with polymer photocatalysts (F8BT), the hydrogen evolution reaction (HER) rate is considerably enhanced by 2.

Revealing the three-dimensional arrangement of polar topology in nanoparticles.

In the early 2000s, low dimensional ferroelectric systems were predicted to have topologically nontrivial polar structures, such as vortices or skyrmions, depending on mechanical or electrical boundary conditions. A few variants of these structures have been experimentally observed in thin film model systems, where they are engineered by balancing electrostatic charge and elastic distortion energies. However, the measurement and classification of topological textures for general ferroelectric nanostructures have remained elusive, as it requires mapping the local polarization at the atomic scale in three dimensions.

Photophore-Anchored Molecular Switch for High-Performance Nonvolatile Organic Memory Transistor.

Over the past decade, molecular-switch-embedded memory devices, particularly field-effect transistors (FETs), have gained significant interest. Molecular switches are integrated to regulate the resistance or current levels in FETs. Despite substantial efforts, realizing large memory window with a long retention time, a critical factor in memory device functionality, remains a challenge.

Liquid-Film Rupture for Web-like Ag Nanowires toward High-Performance Organic Schottky Barrier Transistors.

Organic vertical transistors are promising device with benefits such as high operation speed, high saturation current density, and low-voltage operation owing to their short channel length. However, a short channel length leads to a high off-current, which is undesirable because it affects the on-off ratio and power consumption. This study presents a breakthrough in the development of high-performance organic Schottky barrier transistors (OSBTs) with a low off-current by utilizing a near-ideal source electrode with a web-like Ag nanowire (AgNW) morphology.

Shortwave Infrared Organic Photodiodes Realized by Polaron Engineering.

A novel approach for developing shortwave IR (SWIR) organic photodiodes (OPDs) using doped polymers is presented. SWIR OPDs are challenging to produce because of the limitations in extending the absorption of conjugated molecules and the high dark currents of SWIR-absorbing materials. Herein, it is shown that the conversion of bound polarons to free polarons by light energy can be utilized as an SWIR photodetection mechanism.

Synergistic Contribution of Oligo(ethylene glycol) and Fluorine Substitution of Conjugated Polymer Photocatalysts toward Solar Driven Sacrificial Hydrogen Evolution.

To separately explore the importance of hydrophilicity and backbone planarity of polymer photocatalyst, a series of benzothiadiazole-based donor-acceptor alternating copolymers incorporating alkoxy, linear oligo(ethylene glycol) (OEG) side chain, and backbone fluorine substituents is presented. The OEG side chains in the polymer backbone increase the surface energy of the polymer nanoparticles, thereby improving the interaction with water and facilitating electron transfer to water. Moreover, the OEG-attached copolymers exhibit enhanced intermolecular packing compared to polymers with alkoxy side chains, which is possibly attributed to the self-assembly properties of the side chains.

Azide-functionalized ligand enabling organic-inorganic hybrid dielectric for high-performance solution-processed oxide transistors.

We propose a highly efficient crosslinking strategy for organic-inorganic hybrid dielectric layers using azide-functionalized acetylacetonate, which covalently connect inorganic particles to polymers, enabling highly efficient inter- and intra-crosslinking of organic and inorganic inclusions, resulting in a dense and defect-free thin-film morphology. From the optimized processing conditions, we obtained an excellent dielectric strength of over 4.0 MV cm, a high dielectric constant of ~14, and a low surface energy of 38 mN m.

Direct strain correlations at the single-atom level in three-dimensional core-shell interface structures.

Nanomaterials with core-shell architectures are prominent examples of strain-engineered materials. The lattice mismatch between the core and shell materials can cause strong interface strain, which affects the surface structures. Therefore, surface functional properties such as catalytic activities can be designed by fine-tuning the misfit strain at the interface.

Comparative study of PMS oxidation with Fenton oxidation as an advanced oxidation process for Co-EDTA decomplexation.

In nuclear industry, Co-EDTA complex is generated due to the decontamination activities of nuclear power plants (NPPs). This complex is extremely refractory to the convention methods and can escalate the mobility of Co radionuclide in the environment. Due to its hazardous impact on human and environment, the effective treatments of Co-EDTA complexes are highly recommended.

Direct Observation of Three-Dimensional Atomic Structure of Twinned Metallic Nanoparticles and Their Catalytic Properties.

We determined a full 3D atomic structure of a dumbbell-shaped Pt nanoparticle formed by a coalescence of two nanoclusters using deep learning assisted atomic electron tomography. Formation of a double twin boundary was clearly observed at the interface, while substantial anisotropy and disorder were also found throughout the nanodumbbell. This suggests that the diffusion of interfacial atoms mainly governed the coalescence process, but other dynamic processes such as surface restructuring and plastic deformation were also involved.

Co/PMS based sulfate-radical treatment for effective mineralization of spent ion exchange resin.

Sulfate radical advance oxidation processes (SR-AOPs) have attracted a greater attention as a suitable alternative of the hydroxyl radical based advance oxidation process (HR-AOPs). In this study, for the first time we report liquid phase mineralization of nuclear grade cationic IRN-77 resin in Co/peroxymonosulfate (PMS) based SR-AOPs. After the dissolution of cationic IRN-77 resin, 30 volatile and 15 semi-volatile organic compounds were analyzed/detected using non-targeted GC-MS analysis.

Sublimation-doping with super bases for high-performance solution-processed heterojunction oxide thin film transistors.

We elucidate how non-destructive sublimation-doping of InO/ZnO heterojunctions with various amidine-based organic dopants affects the degree of band bending of the heterojunction and thus the overall performance of solution-processed heterojunction oxide thin-film transistors (TFTs). Ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy analyses show that the stronger the basicity of the dopant, the smaller the - of ZnO that can be induced within a short doping time, resulting in a high electron mobility due to the increased electron density of the InO layer at the vicinity of the heterointerface. Mott-Schottky analysis combined with secondary ion mass spectroscopy shows the preferential modification of - selectively for the ZnO layer.

Development of geopolymer waste form for immobilization of radioactive borate waste.

Radioactive borate waste containing a high concentration of boron (B) is problematic to be solidified using cement because soluble borate such as boric acid hinders the hydration reaction. In this study, borate waste was used as a raw material for metakaolin-based geopolymer according to the characteristic that B replaces a part of Si. Geopolymers using KOH alkaline activator (K-geopolymers) showed higher compressive strength than geopolymers using NaOH alkaline activator (Na-geopolymer).

Single-atom level determination of 3-dimensional surface atomic structure via neural network-assisted atomic electron tomography.

Functional properties of nanomaterials strongly depend on their surface atomic structures, but they often become largely different from their bulk structures, exhibiting surface reconstructions and relaxations. However, most of the surface characterization methods are either limited to 2D measurements or not reaching to true 3D atomic-scale resolution, and single-atom level determination of the 3D surface atomic structure for general 3D nanomaterials still remains elusive. Here we demonstrate the measurement of 3D atomic structure at 15 pm precision using a Pt nanoparticle as a model system.