Fabrication of WO Quantum Dots with Different Emitting Colors and Their Utilization in Luminescent Woods.

With a rising interest in smart windows and optical displays, the utilization of metal oxides (MOs) has garnered significant attention owing to their high active sites, flexibility, and tunable electronic and optical properties. Despite these advantages, achieving precise tuning of optical properties in MOs-based quantum dots and their mass production remains a challenge. In this study, we present an easily scalable approach to generate WO quantum dots with diverse sizes through sequential insertion/exfoliation processes in solvents with suitable surface tension.

An Ultramicroporous Graphene-Based 3D Structure Derived from Cellulose-Based Biomass for High-Performance CO Capture.

The use of powered activated carbon is often limited by inconsistent particle sizes and porosities, leading to reduced adsorption efficiencies. In this study, we demonstrated a practical and environmentally friendly method for creating a 3D graphene nanostructure with highly uniform ultramicropores from wood-based biomass through a series of delignification, carbonization, and activation processes. In addition, we evaluated the capture characteristics of this structure for CO, CH, and N gases as well as its selectivity for binary-mixture gases.

High-Performance Electrochromic Devices Based on Size-Controlled 2D WO Nanosheets Prepared Using the Intercalation Method.

It is difficult to obtain ultrathin two-dimensional (2D) tungsten trioxide (WO) nanosheets through direct exfoliation from bulk WO in solution due to the strong bonding between interlayers. Herein, WO nanosheets with controllable sizes were synthesized via K intercalation and the exfoliation of WO powder using sonication and temperature. Because of the intercalation and expansion in the interlayer distance, the intercalated WO could be successfully exfoliated to produce a large quantity of individual 2D WO nanosheets in -methyl-2-pyrrolidone under sonication.

Hierarchically Porous Carbon Networks Derived from Chitosan for High-Performance Electrochemical Double-Layer Capacitors.

Activated carbon (AC) compounds derived from biomass precursors have garnered significant attention as electrode materials in electric double-layer capacitors (EDLCs) due to their ready availability, cost-effectiveness, and potential for mass production. However, the accessibility of their active sites in electrochemistry has not been investigated in detail. In this study, we synthesized two novel macro/micro-porous carbon structures prepared from a chitosan precursor using an acid/potassium hydroxide activation process and then examined the relationship between their textural characteristics and capacitance as EDLCs.

Effect of Fluorination Position on the Crystalline Structure and Stretchability of Intrinsically Stretchable Polymer Semiconductors.

A clear understanding of the structure-property relationship of intrinsically stretchable polymer semiconductors (ISPSs) is essential for developing high-performance polymer-based electronics. Herein, we investigate the effect of the fluorination position on the crystalline structure, charge-carrier mobility, and stretchability of polymer semiconductors based on a benzodithiophene--benzotriazole configuration. Although four different polymer semiconductors showed similar field-effect mobilities for holes (μ ≈ 0.

Competitive Effects of Oxidation and Quantum Confinement on Modulation of the Photophysical Properties of Metallic-Phase Tungsten Dichalcogenide Quantum Dots.

Metallic-phase transition metal dichalcogenide quantum dots (TMDs-QDs) have been reported in recent years. However, a dominant mechanism for modulating their intrinsic exciton behaviors has not been determined yet as their size is close to the Bohr radius. Herein, we demonstrate that the oxidation effect prevails over quantum confinement on metallic-phase tungsten dichalcogenide QDs (WX-QDs; X = S, Se) when the QD size becomes larger than the exciton Bohr radius.

Graphene Quantum Dots with Blue and Yellow Luminescence Fabricated by Modulating Intercalation State.

The development of graphene quantum dots (GQDs) with low toxicity, excellent dispersibility, and high photostability has led to extensive progress in bio-imaging and optical sensing applications. However, one-pot synthesis and mass production of GQDs, and tuning their photoluminescence, remains a challenge. Here we demonstrate a simple and scalable method for fabricating GQDs with high size uniformity and chemical stability, via a sequential process of inserting alkali metal into graphite (Stage I: KC and Stage II: KC) and exfoliation to GQDs in a selected solvent.

pH-Dependent Photophysical Properties of Metallic Phase MoSe Quantum Dots.

Fluorescence properties of quantum dots (QDs) are critically affected by their redox states, which is important for practical applications. In this study, we investigated the optical properties of MoSe-metallic phase quantum-dots (MoSe-QDs) depending on the pH variation, in which the MoSe-QDs were dispersed in water with two sizes (Φ~3 nm and 12 nm). The larger MoSe-QDs exhibited a large red-shift and broadening of photoluminescence (PL) peak with a constant UV absorption spectra as varying the pH, while the smaller ones showed a small red-shift and peak broadening, but discrete absorption bands in the acidic solution.

Metallic Phase Transition Metal Dichalcogenide Quantum Dots as Promising Bio-Imaging Materials.

Transition metal dichalcogenide-based quantum dots are promising materials for applications in diverse fields, such as sensors, electronics, catalysis, and biomedicine, because of their outstanding physicochemical properties. In this study, we propose bio-imaging characteristics through utilizing water-soluble MoS quantum dots (MoS-QDs) with two different sizes (i.e.

Quaternary Artificial Nacre-Based Electronic Textiles with Enhanced Mechanical and Flame-Retardant Performance.

Interest in wearable electronics has led to extensive studies on woven textiles that are mechanically robust and stretchable, have high electrical conductivities, and exhibit fire resistance properties even at high temperatures. We demonstrate a highly easy and scalable method for fabricating defect-free graphene (G) nacre-based woven electronic textiles (e-textiles) with enhanced flame-retardant properties and high electronic conductivities. The as-prepared graphene shows perfect preservation of its inherent properties without any crystal damage during subsequent exfoliation and noncovalent melamine functionalization.

Synergistic Optimization of the Thermoelectric and Mechanical Properties of Large-Size Homogeneous BiSbTe Bulk Samples via Carrier Engineering for Efficient Energy Harvesting.

Manufacturing an economically viable, efficient commercial thermoelectric (TE) module is essential for power generation and refrigeration. However, mediocre TE properties, lack of good mechanical stability of the material, and significant difficulties involved in the manufacturing of large-scale powder as well as bulk samples hinder the potential applications of the modules. Herein, an economically feasible single-step water atomization (WA) is employed to synthesize BST powder (2 kg) by Cu doping within a short time and consolidated into large-scale bulk samples (500 g) for the first time with a diameter of 50 mm and a thickness of about 40 mm using spark plasma sintering (SPS).

Hydrogen-Bonding-Mediated Molecular Vibrational Suppression for Enhancing the Fluorescence Quantum Yield Applicable for Visual Phenol Detection.

It is generally accepted that while efficient suppression of molecular vibration is inevitable for purely organic phosphors due to their long emission lifetime in the regime of 1 ms or longer, fluorophores having a lifetime in the nanoseconds regime are not sensitive to collisional quenching. Here, however, we demonstrate that a fluorophore, 2,5-bis(hexyloxy)terephthaldehyde (BHTA), capable of having hydrogen bonding (H bonding) via its two aldehyde groups can have a largely enhanced (450%) fluorescence quantum yield (QY) in amorphous poly(acrylic acid) (PAA) matrix compared to its crystalline powder. We ascribe this enhanced QY to the efficient suppression of molecular vibrations via intermolecular H bonding.

Biological Potential of Polyethylene Glycol (PEG)-Functionalized Graphene Quantum Dots in In Vitro Neural Stem/Progenitor Cells.

Stem cell therapy is one of the novel and prospective fields. The ability of stem cells to differentiate into different lineages makes them attractive candidates for several therapies. It is essential to understand the cell fate, distribution, and function of transplanted cells in the local microenvironment before their applications.

Ti₃C₂T MXene-Based Three-Dimensional Architecture for Carbon Dioxide Capture.

Dramatic increases in fossil fuel consumption inevitably led to the emission of huge amounts of CO₂ gas, causing abnormalities in the climate system. Despite continuous efforts to resolve global atmospheric problems through CO₂ capture and separation, success has been limited by poor CO₂ selectivity in the CO₂/N₂ mixture. Herein, we demonstrate the fabrication of a three-dimensional (3D) nanostructure from two-dimensional transition metal carbides (Ti₃C₂T, MXene), and assess its utility as an adsorbent in a CO₂ capture system.

Highly luminescent polyethylene glycol-passivated graphene quantum dots for light emitting diodes.

The emergence of fluorescent graphene quantum dots (GQDs) is expected to enhance the usefulness of quantum dots (QDs), in terms of their unique luminescence, photostability, low toxicity, chemical resistance, and electron transport properties. Here we prepared blue-photoluminescent polyethylene glycol GQDs (PEG-GQDs) through PEG surface passivation. The photoluminescence (PL) quantum yield (QY) of PEG-GQDs with 320 nm excitation was about 4.

Novel Exfoliation of High-Quality 2H-MoS Nanoflakes for Solution-Processed Photodetector.

Highly dispersive molybdenum disulfide nanoflakes (MoS NFs), without any phase transition during the exfoliation process, are desirable for full utilization of their semiconductor properties in practical applications. Here, we demonstrate an innovate approach for fabricating MoS NFs by using hydrazine-assisted ball milling via the synergetic effect of chemical intercalation and mechanical exfoliation. The NFs obtained have a lateral size of 600-800 nm, a thickness less than 3 nm, and high crystallinity in the 2H semiconducting phase.

In Situ Enhanced Raman and Photoluminescence of Bio-Hybrid Ag/Polymer Nanoparticles by Localized Surface Plasmon for Highly Sensitive DNA Sensors.

We experimentally demonstrate the simultaneous enhancement of Raman and photoluminescence (PL) of core-shell hybrid nanoparticles consisting of Ag (core) and polydiacetylene (PDA, shell) through the assistance of localized surface plasmon (LSP) effect for the effective biosensor. Core-shell nanoparticles (NPs) are fabricated in deionized water through a sequential process of reprecipitation and self-assembly. The Raman signal of PDA on core-shell NPs is enhanced more than 100 times.

Synergistic Effect of a Defect-Free Graphene Nanostructure as an Anode Material for Lithium Ion Batteries.

Graphene nanosheets have been among the most promising candidates for a high-performance anode material to replace graphite in lithium ion batteries (LIBs). Studies in this area have mainly focused on nanostructured electrodes synthesized by graphene oxide (GO) or reduced graphene oxide (rGO) and surface modifications by a chemical treatment. Herein, we propose a cost-effective and reliable route for generating a defect-free, nanoporous graphene nanostructure (-GNS) through the sequential insertion of pyridine into a potassium graphite intercalation compound (K-GIC).

Versatile and Tunable Electrical Properties of Doped Nonoxidized Graphene Using Alkali Metal Chlorides.

With the rapid development of wearable and flexible electronics, graphene has been intensively studied for the transparent, hole transport electrode layer (HTL) of field-effect transistors, light-emitting diodes, and organic photovoltaic (OPV) cells. To modulate the sheet resistance and the work function of graphene as a HTL, the surface doping is versatile while retaining high transparency. In this work, we used a chemical doping method to control the charge carrier density, band gap, and work function of graphene with minimizing the damage of the carbon network, for which metal chlorides (NaCl, KCl, and AuCl) were used as chemical dopants.

The Effect of Palm Oil-Based Hybrid Oils as Green Multifunctional Oils on the Properties of Elastomer Composites.

Hybrid oils in an elastomer matrix provide superior physical and chemical properties over conventional elastomer composites. In this study, we investigated the possibility of utilizing palm-based hybrid oil as a processing oil, with various other added oils such as methylester, palm monoglyceride and dammar, and their effects on the curing characteristics, mechanical, abrasion resistance and heat build-up properties of elastomer composites. The elastomer composites with the hybrid oils exhibit remarkable improvements in mechanical properties such as modulus, tensile strength, elongation and toughness, which were ascribed to the enhanced dispersion of the fillers in the elastomer matrix.

Two-Dimensional WO Nanosheets Chemically Converted from Layered WS for High-Performance Electrochromic Devices.

Two-dimensional (2D) transitional metal oxides (TMOs) are an attractive class of materials due to the combined advantages of high active surface area, enhanced electrochemical properties, and stability. Among the 2D TMOs, 2D tungsten oxide (WO) nanosheets possess great potential in electrochemical applications, particularly in electrochromic (EC) devices. However, feasible production of 2D WO nanosheets is challenging due to the innate 3D crystallographic structure of WO.

Tailored Combination of Low Dimensional Catalysts for Efficient Oxygen Reduction and Evolution in Li-O2 Batteries.

The development of efficient bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a key issue pertaining high performance Li-O2 batteries. Here, we propose a heterogeneous electrocatalyst consisting of LaMnO3 nanofibers (NFs) functionalized with RuO2 nanoparticles (NPs) and non-oxidized graphene nanoflakes (GNFs). The Li-O2 cell employing the tailored catalysts delivers an excellent electrochemical performance, affording significantly reduced discharge/charge voltage gaps (1.