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Simple strategy to stably preserve the smaller Ni nanoparticles (NPs) having homogeneous crystallite size of ∼5 nm was proposed using ordered mesoporous supports under dry reforming of methane with CO2 (DRM). The NPs-impregnated ordered mesoporous SBA-15 was effective to preserve the smaller Ni nanoparticles with their lower thermal aggregations and less coke depositions by their spatial confinement effects inside of the ordered mesopore structures compared to the irregular conventional SiO2 support. Although the highly ordered mesoporous NPs-impregnated Al2O3 was also found to be effective, the acidic natures of the Al2O3 surfaces accelerated coke depositions by preferentially forming inactive phases.

A pseudocubic-tetragonal-orthorhombic (PC-T-O) multi-structure was developed in the 0.96(K0.5Na0.47Li0.03) (Nb0.92Sb0.08)O3-0.04(Ca0.5Sr0.5)ZrO3 [(KN0.47L0.03)NS-CSZ] lead-free piezoceramic. The PC structure observed in this sample was deemed to have an R3m rhombohedral structure. This sample demonstrated a large d33 (560 pC/N) owing to the existence of the PC-T-O multi-structure. The (KN0.47L0.03)NS-CSZ thick film also exhibited a large d33 (560 pC/N) and strain (0.19% at 4.0 kV/mm). The large strain was sustained even after the application of 106 electric-field cycles. Therefore, the (KN0.47L0.03)NS-CSZ thick film exhibited excellent fatigue characteristics and was utilized to fabricate a planar-type actuator, which achieved a large displacement (300 μm) and acceleration (872 G) at 125 V/mm. A cantilever-type multilayer actuator was also prepared using five layers of the (KN0.47L0.03)NS-CSZ thick film and demonstrated a large displacement (3500 μm) and acceleration (42.96 G) at 250 V/mm. Therefore, the (KN0.47L0.03)NS-CSZ thick film is a good candidate for fabricating various piezoelectric actuators.

This study examines the effect of MgO content on the crystallization behavior of lithium–aluminum–germanium–phosphate glasses using differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The DTA results show that the crystallization temperature decreased with an increasing MgO content and increased with increasing heating rates. The crystalline phase is investigated with XRD to determine the presence of LiGe2(PO4)3 and LiMgPO4. The activation energy, as the kinetic parameter, is obtained using the Kissinger and Marotta methods, and the SEM results confirm the change in the Avrami index with the MgO content.

The relationships between the structural characteristics and the microwave dielectric properties of the specimens with stoichiometric and non-stoichiometric substitutions were investigated. A single phase with a corundum structure was observed for all compositions of specimens sintered at 1400 °C for 5 h. The microwave dielectric properties of the sintered specimens strongly depended on the type and content of pentavalent cations (e.g., Na5+, Ta5+, Sb5+) in Mg4(NbxTaySbz)O9 ceramics. The Qf value of specimens with stoichiometric substitutions at the Nb site of Mg4Nb2O9 depended on the B-site (i.e., Nb site) bond valence, whereas that of specimens with non-stoichiometric substitutions depended on the packing fraction of the unit cell. The dielectric constants (K) of the specimens did not change remarkably with the composition, and the temperature coefficient of resonant frequency (TCF) depended on the average octahedral distortion.

Hydrogen embrittlement has been recognized as one of major degradation mechanisms causing the decrease of ductility and fracture toughness of several kinds of materials. In accordance with the demand for hydrogen fuels, it becomes more important to ensure safety of relevant facilities like pressure vessels, storage tanks and so on. The objective of this study is to examine fracture resistance of American Petroleum Institute (API)-X70 steel under highly pressurized hydrogen gaseous condition. The extended finite element method (XFEM) was adopted to predict J-R curves via a crack growth simulation approach. At first, preliminary analyses for SM490A carbon steel were carried out to demonstrate applicability of the XFEM, of which result was comparable to test data within 14 %. Subsequently, iterative numerical analyses were conducted to calibrate appropriate damage parameters for the API-X70 steel by using notched round bar specimens. Finally, crack growth simulations of 1T-compact tension (CT) specimens were performed adopting the calibrated parameters. JIC values determined from predicted J-R curves were compared with 1/2T-CT CTOD test data and relevant constraint effect was discussed.

In recent years, two-dimensional transition metal dichalcogenides (TMDs) have been attracted promising candidates for imminent electrical and optical device applications owing to their remarkable properties and unique structures. In this study, we report the optical and electrical characteristics of the newest member of the TMD family, i.e. monolayer of rhenium disulfide (ReS2) field effect transistor on a SiO2/Si substrate developed using the chemical vapor deposition technique. The quality of the as-grown monolayer of ReS2 was evaluated through Raman spectroscopy, whereas the surface elemental composition was analyzed thorough X-ray photoelectron spectroscopy. The optical properties of this monolayer TMD were analyzed using photoluminescence spectroscopy, and the contact resistance between the as-grown semiconducting monolayer and the metal electrodes was examined using the transmission line modeling method. Ti/Au electrodes form an excellent ohmic contact with the monolayers of the ReS2 film. The electron mobility of the monolayer ReS2 FETs fabricated through transmission line patterning was investigated at room temperature (300 K) and found to be $$2.91\hspace{0.17em}\times \hspace{0.17em}$$ 10–2 cm2 V−1 s−1 whereas the on/off ratio of the device was 9.8 × 102.

Functional separators, which are chemically modified and coated with nanostructured materials, are considered an effective and economical approach to suppressing the shuttle effect of lithium polysulfide (LiPS) and promoting the conversion kinetics of sulfur cathodes. Herein, we report cobalt-aluminum-layered double hydroxide quantum dots (LDH-QDs) deposited with nitrogen-doped graphene (NG) as a bifunctional separator for lithium-sulfur batteries (LSBs). The mesoporous LDH-QDs/NG hybrids possess abundant active sites of Co2+ and hydroxide groups, which result in capturing LiPSs through strong chemical interactions and accelerating the redox kinetics of the conversion reaction, as confirmed through X-ray photoelectron spectroscopy, adsorption tests, Li2S nucleation tests, and electrokinetic analyses of the LiPS conversion. The resulting LDH-QDs/NG hybrid-coated polypropylene (LDH-QDs/NG/PP) separator, with an average thickness of ∼17 μm, has a high ionic conductivity of 2.67 mS cm-1. Consequently, the LSB cells with the LDH-QDs/NG/PP separator can deliver a high discharge capacity of 1227.48 mAh g-1 at 0.1C along with a low capacity decay rate of 0.041% per cycle over 1200 cycles at 1.0C.

Solid electrolytes for all-solid-state lithium batteries are excellent in terms of stability, and their performance has been improved through many studies. However, due to the interfacial reaction with lithium and sold electrolyte, there is a problem that the performance is deteriorated when used for a long time. In this study, the charge/discharge evaluation of more than 50 cycles was conducted and we analyzed the change Ti4+ to Ti3+ in the solid electrolyte using X-ray photoelectron spectroscopy. Finally, it was confirmed that the performance of the LiNbO3-coated solid electrolyte did not decrease even after long-term use.

Highlights Ultrathin and defect-free graphene ink is prepared through a high-throughput fluid dynamics process, resulting in a high exfoliation yield (53.5%) and a high concentration (47.5 mg mL−1). A screen-printed graphene conductor exhibits a high electrical conductivity of 1.49 × 104 S m−1 and good mechanical flexibility. An electrochemical sodium ion sensor based on graphene ink exhibits an excellent potentiometric sensing performance in a mechanically bent state. Real-time monitoring of sodium ion concentration in sweat is demonstrated. Abstract Conductive inks based on graphene materials have received significant attention for the fabrication of a wide range of printed and flexible devices. However, the application of graphene fillers is limited by their restricted mass production and the low concentration of their suspensions. In this study, a highly concentrated and conductive ink based on defect-free graphene was developed by a scalable fluid dynamics process. A high shear exfoliation and mixing process enabled the production of graphene at a high concentration of 47.5 mg mL−1 for graphene ink. The screen-printed graphene conductor exhibits a high electrical conductivity of 1.49 × 104 S m−1 and maintains high conductivity under mechanical bending, compressing, and fatigue tests. Based on the as-prepared graphene ink, a printed electrochemical sodium ion (Na+) sensor that shows high potentiometric sensing performance was fabricated. Further, by integrating a wireless electronic module, a prototype Na+-sensing watch is demonstrated for the real-time monitoring of the sodium ion concentration in human sweat during the indoor exercise of a volunteer. The scalable and efficient procedure for the preparation of graphene ink presented in this work is very promising for the low-cost, reproducible, and large-scale printing of flexible and wearable electronic devices.

A novel electroplex host with two triplet exciton up-converting channels for suppressed triplet exciton triggered degradation mechanisms was developed using an electron transport type host (n-type host) with thermally activated delayed fluorescence (TADF) characteristics to improve the device lifetime of deep blue phosphorescent organic light-emitting diodes (PhOLEDs). The TADF-natured n-type host with high triplet energy was derived from triazine with benzonitrile and carbazole units to induce the TADF characteristics. The TADF natured n-type host generated an electroplex with a hole transport type host and the electroplex-based PhOLEDs revealed an extended device lifetime by more than twice compared to the non-TADF natured n-type host based electroplex host. Transient photoluminescence and electroluminescence analyses revealed that two reverse intersystem crossing (RISC) mechanisms through the n-type TADF host and electroplex host could suppress triplet exciton related degradation and improved the device lifetime. Kinetic modeling of the electroplex supported the RISC mechanisms of the electroplex.

In this study, two-dimensional (2D) and exfoliated FeIII nanosheets are prepared using a fast and facile fluid-dynamics-induced exfoliation method for large-scale production. The resulting FeIII nanosheet is ultrathin and of 2D morphology with a high surface area. The FeIII nanosheet exhibits excellent glycolysis-catalytic performance for polyethylene terephthalate (PET) degradation to produce a bis(hydroxyethyl) terephthalate (BHET) monomer. A high PET conversion of 100% and a high BHET yield of 100% using the FeIII nanosheet catalyst are achieved within a short reaction time (30 min) at a reaction temperature of 200 °C. Furthermore, the FeIII nanosheet catalyst shows excellent recyclability for the glycolysis of PET, and a high BHET yield of 96.7% was obtained after five cycles.

This article presents a new practical calibration method of a stripe laser imaging system for the 3-D shape measurement of an object. The proposed calibration method has an integrated mathematical approach for the camera imaging parameters and the stripe laser light plane. A simple calibration block with a checkerboard pattern attached is used that has different inclination angle at each face. Because the same scene with the laser light ON and OFF is used for the integrated calibration of the camera and the laser light plane, the calibration process is fast and efficient and the resultant calibration parameters are consistent. The experimental results demonstrated the performance of the proposed calibration method.

A Fe2O3–added 0.96(K0.5Na0.5)(Nb0.94Sb0.06)–0.01SrZrO3–0.03(BiAg)ZrO3 [KNNS–0.01SZ–0.03BAZ] piezoceramic was well densified at 1090 °C. It exhibited a large piezoelectric charge constant (d33) of 650 pC/N, which is close to the largest d33 value reported in the literature. This sample has a tetragonal–orthorhombic–rhombohedral (T–O–R) structure, in which each structure has a similar proportion. Moreover, nanodomains (2 nm × 15 nm) with a low domain boundary energy were found in this sample, which exhibited relaxor properties. Therefore, the presence of a T–O–R multi-structure and nanodomains is responsible for the large d33 value of this sample. A KNNS–0.01SZ–0.03BAZ thick film was synthesized, and it also had a T–O–R multi-structure with a large d33 (630 pC/N). A planar-type actuator was produced using this thick film, and this actuator exhibited large acceleration (335 G at 120 V mm−1) and displacement (231 μm at 120 V mm−1). Hence, the KNNS–0.01SZ–0.03BAZ thick film is a good candidate for lead-free piezoelectric actuators.

Reported herein are solution-processed polymer anode electrodes for blue phosphorescent organic light-emitting diodes (PhOLEDs). The highly conductive anodes were made from 10-wt%-methyl-red-(MR)-doped poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (PH1000) films. The red-colored and uniform polymer films demonstrated electrical conductivity values that significantly increased from 0.25 to 50 S·cm−1 after doping. The more than 200-fold enhancement in conductivity indicates that the doped films have a lower sheet resistance and better hole injection and transport properties than the pristine films. The resultant PhOLEDs based on the doped polymer anodes exhibited stable, broad, and intense blue emission at 468 nm with a 2616 cd·m−2 maximum luminance and a 4 V turn-on voltage. The obtained study results confirmed the effectiveness of the MR dye as a dopant for the significant enhancement of the conductivity and effective hole injection of PEDOT:PSS. Efficient future flexible optoelectronic applications can be built using this highly conductive polymer electrode obtained via a simple, solution-processed, and cost-effective doping approach.

Nanoparticle supercrystals (NPSCs) are of great interest as materials with emergent properties. Different types of intermolecular forces, such as van der Waals interaction and hydrogen bonding, are present in the NPSCs fabricated to date. However, the limited structural stability of such NPSCs that results from the weakness of these intermolecular forces is a challenge. Here, we report a spontaneous formation of NPSCs driven by covalent bonding interactions, a type of intramolecular force much stronger than the above-mentioned intermolecular forces. A model solution-phase anhydride reaction is used to form covalent bonds between molecules grafted on the surface of gold nanoparticles, resulting in three-dimensional NPSCs. The NPSCs are very stable in different solvents, in dried conditions, and at temperatures as high as 160 °C. In addition to this, the large library of covalent-bond-forming reactions available and the low cost of reactants make the covalent bonding approach highly versatile and economical.

Despite the clear benefits of Na and S active materials, Na–S hybrid energy storage devices have yet to be exploited, and existing Na–S batteries cannot provide fast kinetics and long-term stabilit...

Two-dimensional molybdenum disulfide (MoS2) nanosheets have attracted great attention for electrochemical storage and conversion, but the scalable preparation of highly conductive and stable MoS2 n...

For the evaluation of the residual image suppression, the amorphous indium-gallium-zinc-oxide thin film transistor was manufactured with electric field shield metal on silicon oxide multi-buffer layer, without the need for a silicon crystallization process through the excimer laser process, and is advantageous for the manufacture of large-scale plastic organic light-emitting display. We conducted a study on the propensity to suppress a residual image according to the temperature of the annealing process in amorphous indium gallium zinc oxide. The evaluation divided by the ambient process temperature conditions to measure the change and restoration tendency of the gray current by the black/white current of thin film transistors, and for precise measurement of the current change intervals, the current was analyzed in 0.004 seconds per point. Through the study, residual image of amorphous Indium Gallium Zinc Oxide transistor was found to be suppressed as the temperature of the annealing crystallization increased from 250°C to 325°C, and there was no improvement effect on the 325°C or higher. The trend of threshold voltage shift of thin film transistors according to the two process temperature conditions, 250°C and 325°C, was analyzed by Two sample T analysis method, and the analysis confirmed that the trend of current deterioration is different through p-value 0.007.

Plastic organic light emitting diode displays suffer from residual image, which is closely connected with the hysteresis of the driving thin-film transistor in the pixels. Therefore, in researching paper, we manufactured an OLED display comprise a polyimide substrate and an amorphous indium gallium zinc oxide thin film transistor active layer. Paper proposed a solution for reducing hysteresis through oxygen partial pressure control and evaluated it using hysteresis analysis. The results showed that hysteresis is strongly dependent on the threshold voltage is settled by the oxygen partial pressure while active layer deposition of the TFT. Moreover, hysteresis decreases with increasing temperature.

Flexible, thin, and lightweight supercapacitors have been regarded as important power sources for portable and wearable electronics; however, these are usually limited by relatively low areal or vo...

Transition metal dichalcogenides (TMDs) have attracted significant interest as one of the key materials in future electronics such as logic devices, optoelectrical devices, and wearable electronics. However, a complicated synthesis method and multistep processes for device fabrication pose major hurdles for their practical applications. Here, we introduce a direct and rapid method for layer-selective synthesis of MoS2 and WS2 structures in wafer-scale using a pulsed laser annealing system (λ = 1.06 μm, pulse duration ∼100 ps) in ambient conditions. The precursor layer of each TMD, which has at least 3 orders of magnitude higher absorption coefficient than those of neighboring layers, rigorously absorbed the incoming energy of the laser pulse and rapidly pyrolyzed in a few nanoseconds, enabling the generation of a MoS2 or WS2 layer without damaging the adjacent layers of SiO2 or polymer substrate. Through experimental and theoretical studies, we establish the underlying principles of selective synthesis and optimize the laser annealing conditions, such as laser wavelength, output power, and scribing speed, under ambient condition. As a result, individual homostructures of patterned MoS2 and WS2 layers were directly synthesized on a 4 in. wafer. Moreover, a consecutive synthesis of the second layer on top of the first synthesized layer realized a vertically stacked WS2/MoS2 heterojunction structure, which can be treated as a cornerstone of electronic devices. As a proof of concept, we demonstrated the behavior of a MoS2-based field-effect transistor, a skin-attachable motion sensor, and a MoS2/WS2-based heterojunction diode in this study. The ultrafast and selective synthesis of the TMDs suggests an approach to the large-area/mass production of functional heterostructure-based electronics.

Lead-free NKLNTS ceramics with promising piezoelectric properties were fabricated using the solid phase method, which is a general ceramic manufacturing method. MnO2 was added to NKLNTS ceramics as a sintering aid to improve piezoelectric and dielectric properties. The added MnO2 content was adjusted to 0, 0.1, 0.3, 0.5, and 0.7 wt%, the powder was calcined at 900 °C for 2 h, and then the sintering temperature was changed from 1000 to 1100 °C to study the optimum temperature and composition that yields excellent piezoelectric properties and sinterability. Archimedes method and scanning electron microscope (SEM) were used to evaluate the sinterability, X-ray diffraction analysis (XRD) was performed to confirm the crystallinity of the sintered body, and piezoelectric and dielectric properties were evaluated using a d33-meter and an impedance analyzer. When 0.1 wt% of MnO2 was added, it was confirmed that density was the highest at the sintering temperature of 1050 °C and had excellent piezoelectric and dielectric properties. When 0.3 wt% or more of MnO2 was added, piezoelectric and dielectric properties were decreased due to the decreased density. When NKLNTS-0.1wt% MnO2 was sintered at a sintering temperature of 1050 ℃ for 2 h, it had a density of about 97%. Furthermore, lead-free piezoelectric ceramics with excellent piezoelectric and dielectric properties of d33 = 271 pC/N, kp = 0.40, er = 1250, tan δ = 2.5%, and Tc = 348 °C were fabricated.

The morphology, crystal size, and trap density of perovskite films significantly affect the luminescent properties of perovskite light-emitting diodes (PeLEDs). Recently, numerous studies have been...

High stability, stretchable speed insensitive properties, high stretchability, and electrical conductivity are key characteristics for the realisation of wearable devices. However, conventional research is mainly focused on achieving only high stretchability and electrical conductivity. Studies on the stability and stretching speed insensitive properties generally require complex fabrication processes, which are in need of further improvement. In this study, we propose a facile formation of a conductive bridge in composites by using surface damage and the viscoelastic property of the polymer. Surface cracks due to repeated stretching cycles formed conductive bridges via stress relaxation of the viscoelastic polymer matrix. The conductive bridge resulted in the conductor having highly stable resistance values at target strains and stretching speed insensitive resistance, even at stretching speeds that were 20 times faster than the minimum.

High-capacity electrode materials have been investigated to overcome the low energy density of electrochemical capacitors, but there are still issues arising from the trade-off between charge stora...

In this study, ultrathin and defect-free graphene (Gr) sheets were prepared through a fluid dynamics–induced shear exfoliation method using graphite. The high hydrophobicity and surface area of Gr make it attractive as a solid-contact ion-to-electron transducer for potentiometric K+ sensors, in which the electrodes are fabricated through a screen-printing process. The electrochemical characterization demonstrates that Gr solid contact results in a high double-layer capacitance, potential stability, and strong resistance against water layer, gases, and light. The Gr-based K+ sensors showed a Nernstian slope of 53.53 mV/log[K+] within a linear concentration range of 10−1–10−4 M, a low detection limit of 10−4.28 M, a fast response time of ~8 s, good repeatability, and excellent long-term stability. Moreover, the Gr-based K+ sensors provided accurate ion concentrations in actual samples of human sweat and sports drinks.

Trivalent gallium ion was successfully incorporated into chemically well-defined MgAl-layered double hydroxide (LDH) frameworks through postsynthetic hydrothermal treatment. Quantitative analysis with inductively coupled plasma-mass spectroscopy exhibited that Ga3+ was first incorporated into LDH through partial dissolution-precipitation at the edge of LDH particle and homogeneously distributed throughout the particle by substitution of Ga3+ for Al3+ in LDH frame works. The powder X-ray diffraction patterns showed that the Ga3+ incorporation did not affect the crystal structure without evolution of unexpected impurities. The morphology and surface property of LDH evaluated by scanning electron microscopy and light scattering showed the preservation of physicochemical properties throughout 24 h of hydrothermal reaction. The distribution of incorporated Ga3+ was visualized with energy dispersive spectroscopy-assisted transmission electron microscopy, suggesting the homogeneous location of Ga3+ in an LDH particle. The X-ray absorption near-edge structure and extended X-ray absorption fine structure suggested that the Ga moiety was immobilized in LDH from 0.5 h and readily crystallized upon reaction time.

The effects of residual stress on a tungsten gate in a polysilicon channel in scaled 3D NAND flash memories were investigated using a technology computer-aided design simulation. The NAND strings, with respect to the distance from the tungsten slit, were also analyzed. The scaling of the spacer thickness and hole diameter induced compressive stress on the polysilicon channel. Moreover, the residual stress of polysilicon channel in the string near the tungsten slit had greater compressive stress than the string farther away. The increase in compressive stress in the polysilicon channel degraded the Bit-Line current (Ion) due to stress-induced electron mobility deterioration. Moreover, a threshold voltage shift (∆Vth) occurred in the negative direction due to conduction band lowering.

The strain-dependent nonlinear properties of ground materials, such as shear modulus degradation (G/Gmax) and damping, are of significant importance in seismic-related analyses. However, the ABAQUS program lacks a comprehensive procedure to estimate parameters for a built-in model. In this study, a nonlinear kinematic hardening (NKH) model with three back-stress values was used, which allows better fitting to the backbone curves compared to the simplified nonlinear kinematic hardening (SNKH) model previously proposed. Instead of modeling in ABAQUS, a semi-automated procedure was implemented in MATLAB, which can predict shear stress–shear strain hysteretic loops, to find the fitting parameters to the target G/Gmax and/or damping curves. The procedure was applied for three soil and two rock samples, and the results indicate a good match between model and target backbone curves, which proves the application of the procedure and the NKH model in simulating the nonlinear properties of ground materials.

Fe2O3-added 0.96(K0.5Na0.5)(Nb0.94Sb0.06)-0.01SrZrO3-0.03(BiAg)ZrO3 [KNNS-0.01SZ-0.03BAZ] piezoceramic was well densified at 1090 °C. It exhibited a large piezoelectric charge constant (d33) of 650 pC/N, which is similar to the largest d33 value reported in the literature. This sample has a tetragonal-orthorhombic-rhombohedral (T-O-R) structure, in which each structure has a similar proportion. Moreover, nanodomains (2 nm × 15 nm) with low domain boundary energy were found in this sample, which exhibited relaxor properties. Therefore, the presence of a T-O-R multi-structure and nanodomains is responsible for the large d33 value of this sample. A KNNS-0.01SZ-0.03BAZ thick film was synthesized, and it also had a T-O-R multi-structure with a large d33 (630 pC/N). A planar-type actuator was produced using this thick film, and this actuator exhibited a large acceleration (335 G at 120 V/mm) and displacement (231 μm at 120 V/mm). Hence, the KNNS-0.01SZ-0.03BAZ thick film is a good candidate for lead-free piezoelectric actuators.

We synthesize ZnS–ZnO heterostructure nanorings at ∼680 °C under carrier gases with various [CO2]/[N2] ratios simulating an anoxic and weakly reduced atmosphere on early Earth. The synthesized nanorings consist of a ZnS–ZnO bilayered stem, ZnO teeth, and ZnS wing-like structures between the teeth and the ZnS layer. O atoms are supplied through the decomposition of CO2 presumably catalyzed by the ZnS surface. The respective growth directions of ZnS and ZnO layers in the stem are [0001] and [0111], and ZnO teeth are directed outward from the ring. The nanorings are structurally different from ZnS–ZnO nanorings having inward-directed teeth, which were grown under an oxygen-containing ambient environment. Contrary to the assumption of sulfide dominance including ZnS and MnS while disregarding oxygen-containing minerals such as ZnO on early Earth, we show that ZnS–ZnO nanorings, which are more advantageous in CO2 reduction efficiency, could be formed.

An amphiphilic graft copolymer, composed of poly(β-amino ester)-graft-poly(ethylene glycol) (PAE-g-PEG), was prepared as the drug carrier for treatment of rheumatoid arthritis (RA). PAE-g-PEG was synthesized through Michael addition polymerization and analyzed by 1H nuclear magnetic resonance (1H NMR). Owing to its amphiphilic property, PAE-g-PEG was self-assembled into spherical micelles (23 nm in diameter) in an aqueous environment Methotrexate, a hydrophobic drug for the treatment of RA, was physically loaded into the hydrophobic core of micelles by the dialysis method, resulting in high encapsulation efficiency (85.36%). Dynamic light scattering and transmission electron microscopy revealed that the micellar structure at pH 7.4 rapidly disassociated under the mildly acidic environment (pH < 6.5), mimicking the pathological condition of RA. Owing to the rapid disassociation of PAE-g-PEG micelles, methotrexate in the micelles was rapidly released under the mildly acidic condition. The micelles were non-toxic to and readily taken up by RAW 264.7 cells. When systemically administered into collagen-induced arthritis mice models, the pH-sensitive micelles effectively accumulated in inflamed joints, implying their high targetability to RA. Overall, PAE-g-PEG micelles might be useful as the carrier for targeting RA.

In the synthesis of highly applicable metal–organic frameworks (MOFs), obtaining pure phases poses a great challenge since some MOFs have diverse phases with the same metal sources and ligands. Among such MOFs, PCN-223 and PCN-221 can easily be formed together in a one-pot reaction, making it hard to separate them in a single phase. It is known that some PCN series have a kinetic relationship in the early stages of their formation mechanisms. Thus, we have dedicated our efforts to finding the kinetic relationship between PCN-223 and PCN-221 by utilizing the chemical bath deposition (CBD) method to establish reaction parameters for their pure phases. We found that one out of the two phases can be transformed into the other phase by varying the Zr precursors, water amount, modulators, substrates, and reaction time. Furthermore, the pure phase of PCN-221 with a distinct open-pore channel of 100 nm, which has not been obtained previously, can be synthesized through the CBD method. In this work, we successfully demonstrate that the CBD method is a versatile method for synthesizing phase-pure and uniform MOFs by controlling their nucleation stage and pore structures.

Here, we studied the triboelectric properties of structurally controlled laser-induced graphene (LIG) to clarify the key factors for improving the energy harvesting performance. With a facile defocusing method, the LIG morphology was modulated in porous LIG, in short carbon fiber combined LIG (SF-LIG) and in long carbon fiber-dominant LIG (LF-LIG). Through correlation analysis of the triboelectrification characteristic according to the material properties of LIG, it was found that asymmetric defects as well as the graphitic-N configuration within the fibrous LIG structure can significantly improve the triboelectric effectiveness by supplying trap sites and lowering the work function, respectively. The vertically aligned fibrous structure also increases the structural contact area, contributing to the improvement in the charge transfer efficiency. As a result, it was demonstrated that the long carbon fiber structure of LF-LIG can improve the performance by 130 times (512 mW m−2) compared with porous LIG-based triboelectric nanogenerators (TENGs) (3.9 mW m−2). As a feasible application, all LIG-based flexible triboelectric touch sensors are fabricated, which are composed of LF-LIG active matrices (4 × 4) and LIG electrodes through a one-step laser writing process. The demonstrated touch sensor independently addressed each pixel for tracking the location of the human touch, showing self-powering capabilities. This work presents a facile strategy for surface morphology modification of LIGs and investigates their triboelectric charging effect, which might promote the development of practical flexible TENGs for wearable electronic devices.

In this study, we compared the final core–shell products produced in the presence or absence of ultrasonic waves and evaluated the antibacterial properties of the core–shell. When ultrasonic wave was used, a complete core–shell structure with a silica shell coated on an individual core particle could be observed. Transmission electron microscopy and energy dispersive X-ray spectroscopy were performed to confirm the shape of the core–shell structure formed in each case. In order to evaluate the antibacterial activity of the core–shell with the Cu core, their antibacterial activity was evaluated by the KS J 4206 and JIS Z 2801. The Cu–SiO2 core–shell showed a high level of microbial reduction and it also worked as filler in the glass powder.

High-efficiency solution-processed blue organic light-emitting diodes (OLEDs) were developed using two thermally activated delayed fluorescence (TADF) aromatic molecules, 10-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2,5-dimethylphenyl)-10H-spiro[acridine-9,9′-fluorene] (TXSA) and 10-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-methylphenyl)-10H-spiro[acridine-9,9′-fluorene] (TTSA), composed of spiroacridine donor and triazine acceptor units. As a result, the blue devices based on two novel TADF molecules exhibited remarkable electroluminescence with a high quantum efficiency of 14.94% and current efficiency of 29.29 cd/A by optimization of emitter doping concentration and properties of the electron transporting layer. Our results demonstrate that TXSA and TTSA TADF molecules are prospective materials to fabricate high-performance solution-processed blue OLEDs with a simple device structure.