A5030133810- Graphene research and applications
- Advancements in Battery Materials
- Molecular Junctions and Nanostructures
- Semiconductor materials and devices
- Advanced Battery Materials and Technologies
- Organic Electronics and Photovoltaics
- Diamond and Carbon-based Materials Research
- Force Microscopy Techniques and Applications
- Carbon Nanotubes in Composites
- Ion-surface interactions and analysis
- Advanced battery technologies research
- Electron and X-Ray Spectroscopy Techniques
- 2D Materials and Applications
- Advanced Memory and Neural Computing
- ZnO doping and properties
- Electrocatalysts for Energy Conversion
- Thin-Film Transistor Technologies
- Transition Metal Oxide Nanomaterials
- Quantum Dots Synthesis And Properties
- Advanced Battery Technologies Research
- Catalytic Processes in Materials Science
- Semiconductor materials and interfaces
- Surface and Thin Film Phenomena
- Extraction and Separation Processes
- Ga2O3 and related materials
Pohang University of Science and Technology
2016-2025
Pohang Accelerator Laboratory
2015-2025
Pohang TechnoPark (South Korea)
2022
Hongik University
2003
Abstract In this study, we employ a combination of various in-situ surface analysis techniques to investigate the thermally induced degradation processes in MAPbI 3 perovskite solar cells (PeSCs) as function temperature under air-free conditions (no moisture and oxygen). Through comprehensive approach that combines grazing-incidence wide-angle X-ray diffraction (GIWAXD) high-resolution photoelectron spectroscopy (HR-XPS) measurements, confirm structure film changes an intermediate phase...
The polarity of oxide surfaces can dramatically impact their surface reactivity, in particular, with polar molecules such as water. species that result from this interaction change the electronic structure and chemical reactivity applications photoelectrochemistry but are challenging to probe experimentally. Here, we report a detailed study chemistry perovskite LaFeO3 humid conditions using ambient-pressure X-ray photoelectron spectroscopy. Comparing two possible terminations (001)-oriented...
Abstract A high‐rate of oxygen redox assisted by cobalt in layered sodium‐based compounds is achieved. The rationally designed Na 0.6 [Mg 0.2 Mn Co ]O 2 exhibits outstanding electrode performance, delivering a discharge capacity 214 mAh g −1 (26 mA ) with retention 87% after 100 cycles. High rate performance also achieved at 7C (1.82 107 . Surprisingly, the compound able to deliver for 1000 cycles 5C (at 1.3 ), retaining 72% its initial 108 X‐ray absorption spectroscopy analysis O K‐edge...
Potassium oxide (K2O) is used as a promotor in industrial ammonia synthesis, although metallic potassium (K) better theory. The reason K2O because K, which volatilizes around 400 °C, separates from the catalyst harsh synthesis conditions of Haber-Bosch process. To maximize efficiency using K with low temperature reaction below °C prerequisite. Here, we synthesize and Fe via mechanochemical process near ambient (45 1 bar). final concentration reaches high 94.5 vol%, was extraordinarily higher...
Boosting dielectric permittivity representing electrical polarizability of materials has been considered a keystone for achieving scientific breakthroughs as well technological advances in various multifunctional devices. Here, we demonstrate sizable enhancements low-frequency responses oxygen-deficient oxide ceramics through specific treatments under humid environments. Ultrahigh (~5.2 × 10 6 at 1 Hz) is achieved by hydrogenation, when Ni-substituted BaTiO 3 are exposed to high humidity....
To investigate the effects of metal penetration into organic semiconductors on electrical properties thin film transistors, gold was deposited onto pentacene films at various deposition rates. The sharp interface between electrode and that results from a fast rate found to produce lower contact resistance an increase in field-effect mobility.
Impressive optical properties of graphene have been attracting the interest researchers, and, recently, photovoltaic effects a heterojunction structure embedded with few layer (FLG) demonstrated. Here, we show direct dependence open-circuit voltage (Voc) on numbers layers. After unavoidably adsorbed contaminants were removed from FLGs, by means in situ annealing, prepared layer-by-layer transfer chemically grown layer, work functions FLGs showed sequential increase as layers increase,...
In situ exsolution of metal nanoparticles (NPs) is emerging as an alternative technique to deliver thermally stable and evenly dispersed NPs, which exhibit excellent adhesion with conducting perovskite oxide supports. Here we provide the first demonstration that Ni NPs high areal density (∼175 μm-2) fine size (∼38.65 nm) are exsolved from A-site-deficient stannate support (La0.2Ba0.7Sn0.9Ni0.1O3-δ (LBSNO)). The strongly anchored impart coking resistance, Ni-exsolved stannates show...
In the last few decades, numerous studies have focused on designing suitable hydrophilic materials to inhibit surface-induced fog or frost under extreme conditions. As fogging and condensation frosting a film involves molecular interaction with water prior forming discrete droplets surface, it is essential control extent of strongly bind molecules for antifogging coatings. While contact angle measurement commonly used probe hydrophilicity film, oftentimes fails predict antifrosting...
Transition metal dichalcogenides (TMDs) benefit electrical devices with spin-orbit coupling and valley- topology-related properties. However, TMD-based suffer from traps arising defect sites inside the channel gate oxide interface. Deactivating them requires independent treatments, because origins are dissimilar. This study introduces a single treatment to passivate defects in multilayer MoS2 FET. By applying back-gate bias, protons an H-TFSI droplet injected into MoS2, penetrating deeply...
Abstract This study explores the impact of introducing vacancy in transition metal layer rationally designed Na 0.6 [Ni 0.3 Ru Mn 0.4 ]O 2 (NRM) cathode material. The incorporation Ru, Ni, and enhances structural stability during extensive cycling, increases operation voltage, induces a capacity increase while also activating oxygen redox, respectively, 0.7 0.2 V Ni0.1 (V-NRM) compound. Various analytical techniques including transmission electron microscopy, X-ray absorption near edge...
We have investigated the effects of a buffer layer insertion on performance pentacene based thin film transistor with bottom contact structure. When molecules standing up coordination Au surface that is modified by benzenethiol or methanethiol, transition region in removed along boundary between and silicon oxide region, hole-injection barrier decreases 0.4eV. Pentacene various surfaces showed highly occupied molecular level 0.2–0.4eV lower than lying down coordination.
Polymer dielectric materials with hydroxyl functionalities such as poly(4-vinylphenol) and poly(vinyl alcohol) have been utilized widely in organic thin-film transistors (OTFTs) because of their excellent insulating performance gained by hydroxyl-mediated cross-linking. However, the polar functionality also deleteriously affects OTFTs significantly impairs device stability. In this study, a sub-20 nm, high-k copolymer functionality, poly(2-hydroxyethyl acrylate-co-di(ethylene glycol) divinyl...
van der Waals (vdW) materials have shown unique electrical and optical properties depending on the thickness due to strong interlayer interaction symmetry breaking at monolayer level. In contrast, study of tribological their thickness-insensitivity oxides are lacking difficulties in fabrication high quality two-dimensional investigation nanoscale properties. Here we investigated various properties, such as, friction, adhesion, work function, tunnel current, dielectric constant,...
Abstract Area‐selective deposition is a key method for enhancing precision in nanofabrication, particularly next‐generation semiconductor devices. (N,N‐dimethylamino)trimethylsilane (DMATMS) attracting increasing attention its ability to form selective inhibition layer on technologically important surfaces. However, direct observation of this molecular challenging because the limited analysis methods available tracing monolayer chemistry. This study employs situ spectroscopy investigate...
Carbon hydrogasification is the slowest reaction among all carbon-involved small-molecule transformations. Here, we demonstrate a mechanochemical method that results in both faster rate and new synthesis route. The was dramatically enhanced by up to 4 orders of magnitude compared traditional thermal method. Simultaneously, exhibited very high selectivity (99.8 % CH4 , versus 80 under conditions) with cobalt catalyst. Our study demonstrated this extreme increase originates from continuous...
Abstract Although metal exsolution from perovskite materials effectively improves catalytic activity, its high temperature and prolonged operation time present challenges for industrial synthesis efficiency scalability, emphasizing the necessity straightforward scalable fabrication methods at lower temperatures. Herein, a novel catalyst approach through bead milling of nanoparticles are introduced to achieve low‐temperature (300 °C) exsolution. The process reduces particle size less than 50...