Science Daily March 19, 2024 Mesoporous metal oxides exhibit excellent physicochemical properties and are widely used in various fields, including energy storage/conversion, catalysis, and sensors. Although several soft-template approaches are reported, high-temperature calcination for both metal oxide formation and template removal is necessary, which limits direct synthesis on a plastic substrate for flexible devices. Researchers in South Korea developed a universal synthetic approach that combines thermal activation and oxygen plasma to synthesize diverse mesoporous metal oxides (V2O5, V6O13, TiO2, Nb2O5, WO3, and MoO3) at low temperatures (150–200 °C), which could be applied to a flexible polymeric substrate. To demonstrate their […]
Tag Archives: S&T South Korea
Researchers develop world’s most efficient quantum dot solar cell
Nanowerk February 21, 2024 Research has predominantly focused on inorganic cation perovskite-based colloidal quantum dots (PQDs) even though organic cation PQDs have more favorable bandgaps. Researchers in South Korea developed solar cells using narrow bandgap organic cation based PQDs and demonstrated substantially higher efficiency compared with their inorganic counterparts. They employed an alkyl ammonium iodide-based ligand exchange strategy, which proved to be substantially more efficient in replacing the long-chain oleyl ligands than conventional methyl acetate-based ligand exchange while stabilizing the α phase of organic PQDs in ambient conditions. They showed a solar cell with the organic cation PQDs with high […]
Joint research team develops edge-to-edge assembly technique for 2D nanosheets
Phys.org February 2, 2024 Despite remarkable advancements, the controlled assembly of highly anisotropic 2Dnanosheets is significantly challenging, primarily due to the limited availability of selective edge-to-edge connectivity compared to the abundant large faces. Researchers in South Korea have shown controlled self-assembly of 2D-silica nanosheets (2D-SiNSs) into hollow micron-sized soccer ball-like shells (SA-SiMS). The assembly was driven by the physical flexibility of the 2D-SiNSs and the differential electric double-layer charge gradient creating electrostatic bias on the edge and face regions. The resulting SA-SiMS structures exhibited high mechanical stability, even at high-temperatures, and exhibited excellent performance as catalyst support in the dry […]
Key innovation in photonic components could transform supercomputing technology
Phys.org February 5, 2024 Researchers in South Korea demonstrated the array-level tunable couplers and phase shifters with capacitive electrostatic microelectromechanical actuators in a recirculating mesh network. The overall fabrication process was compatible with the conventional wafer-level passive silicon photonics platform. Extremely low unit-level standby power consumption of and reconfiguration energy with <11 V programming voltages offered well-balanced, scalable routes for efficient phase and amplitude modulation of the guided lightwaves with sub-decibel optical losses. The extinction ratios of the continuously tunable directional coupler exceed 30 dB. Full 2π-phase shifting could be achieved with a modulation efficiency of less than 0.075 V cm and a phase-dependent […]
New ionic MOF materials boost hydrogen fuel cell efficiency
Nanowerk September 11, 2023 A few MOFs which typically use strong acids as proton sources, display superprotonic conductivity. However, they are rare due to the instability of MOFs in highly acidic conditions. Researchers in South Korea have shown superprotonic conductivity using a moderately acidic guest, zwitterionic sulfamic acid (HSA), which was encapsulated in MOF-808 and MIL-101. HSA acted not only as a proton source but also as a proton-conducting medium due to its extensive hydrogen bonding ability and zwitterion effect. A new sustained concentration gradient method resulted in higher HSA encapsulation compared to conventional methods. The MOFs showed impressive superprotonic […]
Scientists develop an energy-efficient wireless power and information transfer system
Science Daily September 5, 2023 A simultaneous wireless information and power transfer (SWIPT)-enabled nonorthogonal multiple access (NOMA) system has been recognized as a promising technology for enabling the Industrial Internet of Things (IIoT), as it extends the lifetime of small battery-driven sensors. However, its energy efficiency significantly decreases with distance from the central controller. Researchers in South Korea proposed a framework for applying SWIPT-aided NOMA system to a distributed antenna system (DAS) to improve the spectral efficiency and energy efficiency of the IIoT. They optimized the power allocation for the NOMA signaling and power splitting for SWIPT in the DAS […]
Micro-optical technology based on metamaterials takes center stage
Phys.org August 30, 2023 To date research on metasurfaces has mainly focused on the full control of electromagnetic characteristics, including polarization, phase, amplitude, and even frequencies. Consequently, versatile possibilities of electromagnetic wave control have been achieved, yielding practical optical components such as metalenses, beam-steerers, metaholograms, and sensors. Researchers in South Korea focused on integrating the metasurfaces with other standard optical components for commercialization with miniaturization trends of optical devices. In this review they described and classified metasurface-integrated optical components, and subsequently discussed their promising applications with metasurface-integrated optical platforms including those of augmented/virtual reality, light detection and ranging, and sensors. […]
Researchers take a closer look at ultra-high stability nanobubbles
Phys.org July 24, 2023 Bubble technology has proven to be an efficient technique of reducing environmental pollution, strengthening water treatment procedures, and increasing production in industrial and agricultural applications. Nanobubbles (NBs) in liquids have several intriguing properties, including low buoyancy, high mass transfer efficiency, and high reactivity. In particular, NBs smaller than 200 nm are unexpectedly stable. However, determining the underlying mechanism of the stability of NBs in a solution is difficult. Researchers in South Korea investigated the number and stability of high-concentration NBs under various conditions. The results showed that the number and concentration of NBs can be maintained […]
Three-dimensional structure control technology enables high-performance fuel cells with higher stability
Nanowerk July 26, 2023 Over the past few decades, considerable advances have been achieved in polymer electrolyte membrane fuel cells (PEMFCs) based on the development of material technology. Recently, an emerging multiscale architecting technology covering nanometer, micrometer, and millimeter scales has been regarded as an alternative strategy to overcome the hindrance to achieving high-performance and reliable PEMFCs. In their review article researchers in South Korea provided summaries of progress in the key components of PEMFCs based on a novel architecture strategy. In the first section, diverse architectural methods for patterning the membrane surface with random, single-scale, and multiscale structures as […]
Researchers develop a current collector for energy storage devices with high-efficiency and long cycling life
Nanowerk June 21, 2023 Researchers in South Korea used to prepare floating catalyst–chemical vapor deposition-derived CNT sheets for potential use as all-around current collectors in two representative energy storage devices: batteries and electrochemical capacitors. CNT-based current collectors enhance ion transport kinetics and provide many ion adsorption and desorption sites, which are crucial for improving the performance of batteries and electrochemical capacitors. They demonstrated high-performance lithium-ion hybrid capacitors (LIHCs) by assembling activated carbon–CNT cathodes and prelithiated graphite–CNT anodes. CNT-based LIHCs exhibit 170% larger volumetric capacities, 24% faster rate capabilities, and 21% enhanced cycling stabilities relative to LIHCs based on conventional metallic […]