Continuously Adjustable Thickness of Bi2MoO6 Nanosheets Enhances Photocatalytic Oxidation.

In this study, two-dimensional (2D) nanosheet photocatalysts of Bi2MoO6 with varying thicknesses were synthesized by adjusting the temperature during the hydrothermal reaction. The thinnest Bi2MoO6 nanosheet reached an approximate thickness of ∼4 nm, while the thickest nanosheet measured only ∼16 nm. The photocatalytic performance for Rhodamine B (RhB) degradation was found to be the most effective for the thinnest Bi2MoO6 nanosheet, displaying a degradation rate constant of 0.11 min-1. This rate was 2.5 times higher than that observed for the ∼16 nm thick Bi2MoO6 photocatalyst. The enhanced performance of the thinner two-dimensional nanostructure can be attributed to improved separation and migration of photogenerated charges. Additionally, the study identified hydroxyl radicals (•OH) and superoxide radicals (•O2-) as crucial oxidative species, contributing to the efficient mineralization of RhB dye. This work highlights the controllable synthesis of 2D materials with varying thicknesses and their specific applications in photocatalytic oxidation.

Enhancement of the Josephson Current in a Quantum Dot Connected to Majorana Nanowires.

We investigate the behavior of the Josephson current in a system composed of a quantum dot (QD) sandwiched between two nanowires by using the nonequilibrium Green's function technique. We consider that the nanowires are in proximity to s-wave superconducror substrates, and Majorana bound states (MBSs) are induced at their ends. It is also assumed that the two nanowires are not aligned in the same orientation, but form a bent angle with respect to each other. It is found that when only one spin state on the QD is coupled to the left nanowire, the Josephson current is the typical sinusoidal function of the phase difference between the two nanowires. If both spin states hybridize to the MBSs with equal coupling strengths, the Josephson current then is not a sinusoidal function of the phase difference. In particular, when the bent angle between the two nanowires is π/2 and the two modes of the MBSs in each nanowire are decoupled from each other, the Josephson current is enhanced by about twenty times in magnitude as compared to the former case. Moreover, the simultaneously enhanced currents of the two spin directions are of the same magnitude but flow in opposite directions and they induce a large pure spin current. Our results also show that this abnormally enhanced Josephson current will be suppressed by a vertical magnetic field applied to the QD.

A Novel Surface Modification on Core-Shell Yellow Particles for Electrophoretic Display.

This paper reports the synthesis of yellow-charged particles with a core-shell structure by modifying yellow pigment 181 particles using an ionic liquid under the sol-gel and grafting methods. The core-shell particles were characterized using various methods, including energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, colorimetry, thermogravimetric analysis, and others. The changes in zeta potential and particle size before and after modification were also measured. The results demonstrate that the surface of the PY181 particles was successfully coated with SiO2 microspheres, resulting in weak color change but increased brightness. The shell layer also caused an increase in the particle size. Moreover, the modified yellow particles exhibited apparent electrophoretic response, indicating improved electrophoretic properties. The core-shell structure significantly enhanced the performance of organic yellow pigment PY181, making this method a practical modification approach. This method provides a novel way of improving the electrophoretic performance of color pigment particles that are challenging to directly connect with an ionic liquid, leading to the improved electrophoretic mobility of pigment particles. It is suitable for the surface modification of various pigment particles.

A crack templated copper network film as a transparent conductive film and its application in organic light-emitting diode.

In this paper, a highly transparent, low sheet resistance copper network film fabricated by a crack template, which made by drying an acrylic based colloidal dispersion. The fabricated copper network film shows excellent optoelectronic performances with low sheet resistance of 13.4 Ω/sq and high optical transmittance of 93% [excluding Polyethylene terephthalate (PET) substrate] at 550 nm. What's more, the surface root mean square of the copper network film is about 4 nm, and the figure of merit is about 380. It's comparable to that of conventional indium tin oxide thin film. The repeated bending cycle test and adhesive test results confirm the reliability of the copper network film. As a transparent conductive film, the copper network film was used as an anode to prepare organic light-emitting diode (OLED). The experiment results show that the threshold voltage of the OLED is less than 5 V and the maximum luminance is 1587 cd/m2.

Facile Preparation of Four-Layer MoS2 Nanosheets and Their Application to Organic Light-Emitting Diode.

High-quality four-layer molybdenum disulfide (MoS2) nanosheets with lateral dimension of about 11 µm were prepared by ultrasonic treatment of MoS2 powder with assistance of 1-methyl-2-pyrrolidone (NMP) solvent. The optimal preparation conditions for the preparation of MoS2 nanosheets were investigated from the aspects of ultrasonic processing time, ultrasonic power and amount ratio of MoS2 powder and NMP solvent. At the same time, the MoS2 nanosheets were employed as anode buffer layer in organic light-emitting diode (OLED) with copper nanowire (CuNW) film being anode. MoS2 nanosheets can reduce roughness of CuNW film, protect CuNW film from oxidation and improve work function of CuNW film. Experiments show that MoS2 nanosheets can significantly improve the current density and brightness of the OLED with CuNW film being anode. The maximum brightness of the OLED with MoS2 anode buffer layer is 2.15 times that of the OLED without MoS2 anode buffer layer. The current density of the OLED with MoS2 anode buffer layer is also obviously increased compared with the OLED without MoS2 anode buffer layer.

NaCl-Assisted Chemical Vapor Deposition of Large-Domain Bilayer MoS2 on Soda-Lime Glass.

In recent years, two-dimensional molybdenum disulfide (MoS2) has attracted extensive attention in the application field of next-generation electronics. Compared with single-layer MoS2, bilayer MoS2 has higher carrier mobility and has more promising applications for future novel electronic devices. Nevertheless, the large-scale low-cost synthesis of high-quality bilayer MoS2 still has much room for exploration, requiring further research. In this study, bilayer MoS2 crystals grown on soda-lime glass substrate by sodium chloride (NaCl)-assisted chemical vapor deposition (CVD) were reported, the growth mechanism of NaCl in CVD of bilayer MoS2 was analyzed, and the effects of molybdenum trioxide (Mo) mass and growth pressure on the growth of bilayer MoS2 under the assistance of NaCl were further explored. Through characterization with an optical microscope, atomic force microscopy and Raman analyzer, the domain size of bilayer MoS2 prepared by NaCl-assisted CVD was shown to reach 214 µm, which is a 4.2X improvement of the domain size of bilayer MoS2 prepared without NaCl-assisted CVD. Moreover, the bilayer structure accounted for about 85%, which is a 2.1X improvement of bilayer MoS2 prepared without NaCl-assisted CVD. This study provides a meaningful method for the growth of high-quality bilayer MoS2, and promotes the large-scale and low-cost applications of CVD MoS2.

Chemical Vapor Deposition of Uniform and Large-Domain Molybdenum Disulfide Crystals on Glass/Al2O3 Substrates.

Two-dimensional molybdenum disulfide (MoS2) has attracted significant attention for next-generation electronics, flexible devices, and optical applications. Chemical vapor deposition is the most promising route for the production of large-scale, high-quality MoS2 films. Recently, the chemical vapor deposition of MoS2 films on soda-lime glass has attracted great attention due to its low cost, fast growth, and large domain size. Typically, a piece of Mo foil or graphite needs to be used as a buffer layer between the glass substrates and the CVD system to prevent the glass substrates from being fragmented. In this study, a novel method was developed for synthesizing MoS2 on glass substrates. Inert Al2O3 was used as the buffer layer and high-quality, uniform, triangular monolayer MoS2 crystals with domain sizes larger than 400 µm were obtained. To demonstrate the advantages of glass/Al2O3 substrates, a direct comparison of CVD MoS2 on glass/Mo and glass/Al2O3 substrates was performed. When Mo foil was used as the buffer layer, serried small bilayer islands and bright core centers could be observed on the MoS2 domains at the center and edges of glass substrates. As a control, uniform MoS2 crystals were obtained when Al2O3 was used as the buffer layer, both at the center and the edge of glass substrates. Raman and PL spectra were further characterized to show the merit of glass/Al2O3 substrates. In addition, the thickness of MoS2 domains was confirmed by an atomic force microscope and the uniformity of MoS2 domains was verified by Raman mapping. This work provides a novel method for CVD MoS2 growth on soda-lime glass and is helpful in realizing commercial applications of MoS2.

Application of High Potential Electrophoretic Particles Modified with High Ionization Mono Ionic Liquid for Electrophoretic Displays.

The electrophoretic display (EPD) has attracted widespread attention due to its great visual perception, energy-saving, portability, and bistability. However, the EPD still has many problems in response time, colorization, etc., which limits its practical application. In this paper, novel blue electrophoretic particles were prepared with copper (II) phthalocyanine and high ionization 1-butyl-1-methyl piperidinium bromide mono ionic liquid. It was shown that electrophoretic particles dispersed in a non-polar tetrachloroethylene medium had high Zeta potential and electrophoretic mobility. At the same time, electrophoretic particles showed better dispersion stability. Finally, the prepared blue electrophoretic particles and white titanium dioxide particles were compounded to prepare blue and white dual-color electrophoretic dispersion. An EPD cell was made to test its performance. The results showed that the prepared blue and white dual-color electrophoretic dispersion could realize a reversible response. Piperidine mono ionic liquid increased the surface potential of copper (II) phthalocyanine from +30.50 mV to +60.27 mV, enhancing it by 97.61%. Therefore, we believed that modifying particles with high ionization mono ionic liquid had great applicability to the modification of electrophoretic particles, and blue particles prepared with piperidine mono ionic liquid as a charge control agent (CCA) were excellent candidates for EPDs.

A Novel Modification of Copper (II) Phthalocyanine Particles towards Electrophoretic Displays.

Electrophoretic display (EPD) is a popular display technology in recent years. The core of the EPD is electrophoretic particles, and its Zeta potential has an important impact on EPDs. In this work, a method using pyrrolidine mono ionic liquid was proposed to improve the Zeta potential of electrophoretic particles: Copper (II) phthalocyanine pigment was modified with mono ionic liquid 1-Butyl-1-methylpyrrolidinium bromide. The characterization results show that the mono ionic liquid had been successfully coated on pigment particles. At the same time, the dispersion and stability of particles were improved. The modified Copper (II) phthalocyanine pigment could be stably dispersed in tetrachloroethylene for more than 20 days. The Zeta potential increased from 32.42 mV to 49.91 mV, increasing by 53.95%. Finally, the prepared blue electrophoretic particles were compounded with white titanium dioxide to prepare blue and white dual-color electrophoretic dispersion, and then an EPD cell was designed to test its performance. The results show that the prepared electrophoretic dispersion can realize reversible reciprocating motion. Therefore, because of the unique structure and properties of pyrrolidine mono ionic liquids, the blue nanoparticles prepared with pyrrolidine ionic liquids as charge control agents in this study can be used as excellent candidate materials for EPD.

Synthesis of Single-Crystal Graphene on Copper Foils Using a Low-Nucleation-Density Region in a Quartz Boat.

The nucleation of graphene at different locations in the quartz boat was studied, and the lowest nucleation density of graphene in the quartz boat was found. The nucleation density of graphene is the lowest at the bottom of the quartz boat near the gas inlet side. Based on the above results, a simple and reproducible way is proposed to significantly suppress the nucleation density of graphene on the copper foil during the chemical vapor deposition process. Placing the copper foil with an area of 1.3 cm × 1 cm in the middle of the bottom of the quartz boat or further back, and placing two copper pockets in front of the copper foil, an ultra-low nucleation density of ~42 nucleus/cm2 was achieved on the back of the copper foil. Single-crystal monolayer graphene with a lateral size of 800 µm can be grown on the back of copper foils after 60 min of growth. Raman spectroscopy revealed the single-crystal graphene to be in uniform monolayers with a low D-band intensity.

Effect of Back-Gate Voltage on the High-Frequency Performance of Dual-Gate MoS2 Transistors.

As an atomically thin semiconductor, 2D molybdenum disulfide (MoS2) has demonstrated great potential in realizing next-generation logic circuits, radio-frequency (RF) devices and flexible electronics. Although various methods have been performed to improve the high-frequency characteristics of MoS2 RF transistors, the impact of the back-gate bias on dual-gate MoS2 RF transistors is still unexplored. In this work, we study the effect of back-gate control on the static and RF performance metrics of MoS2 high-frequency transistors. By using high-quality chemical vapor deposited bilayer MoS2 as channel material, high-performance top-gate transistors with on/off ratio of 107 and on-current up to 179 µA/µm at room temperature were realized. With the back-gate modulation, the source and drain contact resistances decrease to 1.99 kΩ∙µm at Vbg = 3 V, and the corresponding on-current increases to 278 µA/µm. Furthermore, both cut-off frequency and maximum oscillation frequency improves as the back-gate voltage increases to 3 V. In addition, a maximum intrinsic fmax of 29.7 GHz was achieved, which is as high as 2.1 times the fmax without the back-gate bias. This work provides significant insights into the influence of back-gate voltage on MoS2 RF transistors and presents the potential of dual-gate MoS2 RF transistors for future high-frequency applications.

High-Performance CVD Bilayer MoS2 Radio Frequency Transistors and Gigahertz Mixers for Flexible Nanoelectronics.

Two-dimensional (2D) MoS2 have attracted tremendous attention due to their potential applications in future flexible high-frequency electronics. Bilayer MoS2 exhibits the advantages of carrier mobility when compared with monolayer mobility, thus making the former more suitable for use in future flexible high-frequency electronics. However, there are fewer systematical studies of chemical vapor deposition (CVD) bilayer MoS2 radiofrequency (RF) transistors on flexible polyimide substrates. In this work, CVD bilayer MoS2 RF transistors on flexible substrates with different gate lengths and gigahertz flexible frequency mixers were constructed and systematically studied. The extrinsic cutoff frequency (fT) and maximum oscillation frequency (fmax) increased with reducing gate lengths. From transistors with a gate length of 0.3 µm, we demonstrated an extrinsic fT of 4 GHz and fmax of 10 GHz. Furthermore, statistical analysis of 14 flexible MoS2 RF transistors is presented in this work. The study of a flexible mixer demonstrates the dependence of conversion gain versus gate voltage, LO power and input signal frequency. These results present the potential of CVD bilayer MoS2 for future flexible high-frequency electronics.

Effect of the Pressure of Reaction Gases on the Growth of Single-Crystal Graphene on the Inner Surfaces of Copper Pockets.

Single-crystal graphene has attracted much attention due to its excellent electrical properties in recent years, and many growth methods have been proposed, including the copper pockets method. In the copper pockets method, a piece of copper foil is folded into a pocket and put into a chemical vapor deposition (CVD) system for the growth of graphene. The dynamic balance of evaporation and deposition of copper on the inner surfaces of the copper pockets avoids high surface roughness caused by the evaporation of copper in open space, such as the outer surfaces of copper pockets. Much lower partial pressure of methane in the copper pockets and lower surface roughness reduce the nucleation density of graphene and increase the size of single-crystal graphene. It is found that the growth pressure is closely related to the size of single-crystal graphene prepared by the copper pockets method; the higher the growth pressure, the larger the size of single-crystal graphene. It is also found that the growth pressure has an effect on the inner surface roughness of the copper pockets, but the effect is not significant. The main factor affecting the size of the single-crystal graphene is the change in the volume of the copper pockets caused by the change in the growth pressure, and the volume of the copper pockets determines the content of methane in the copper pockets. According to the above law, the size of single-crystal graphene prepared by the copper pockets method can be enlarged by increasing the growth pressure. The size of single-crystal graphene can be enlarged in a wide range as the growth pressure can be increased in a wide range. In our experiments, when the growth pressure reached 450 Pa, single-crystal graphene with a diameter of 450 µm was prepared.

Penile resurfacing using a reverse bilateral anterior scrotal artery flap: A case report of penile skin defects following circumcision.

RATIONALE: Circumcision is one of the most frequently used surgical procedures worldwide. Extensive penile skin defects, which can occur as a rare but severe complication of circumcision, are serious and frustrating problems for patients who experience them. Procedures for correcting these problems can pose a challenge to plastic surgeons in the clinic. PATIENT CONCERNS: A 31-year-old man was admitted to our care with an extensive defect of the penile skin caused by a circumcision performed 20 days previously. PRIMARY DIAGNOSES: Infection, necrosis, and defects of the penile skin. INTERVENTIONS: A reverse bilateral anterior scrotal flap was used to correct complete penile skin loss following debridement of the infected and necrotic tissue. OUTCOMES: The patient experienced no complications during the 10-year follow-up period. The patient reported normal erectile function and the ability to perform intercourse. LESSONS: The reverse bilateral anterior scrotal artery flap is suitable for repairing skin defects of the penis and allows for satisfactory cosmetic and functional improvement following defects of the penile skin.

Nanometre-thin indium tin oxide for advanced high-performance electronics.

Although indium tin oxide (ITO) is widely used in optoelectronics due to its high optical transmittance and electrical conductivity, its degenerate doping limits exploitation as a semiconduction material. In this work, we created short-channel active transistors based on an ultra-thin (down to 4 nm) ITO channel and a high-quality, lanthanum-doped hafnium oxide dielectric of equivalent oxide thickness of 0.8 nm, with performance comparative to that of existing metal oxides and emerging two-dimensional materials. Short-channel immunity, with a subthreshold slope of 66 mV per decade, off-state current <100 fA µm-1 and on/off ratio up to 5.5 × 109, was measured for a 40-nm transistor. Logic inverters working in the subthreshold regime exhibit a high gain of 178 at a low-supply voltage of 0.5 V. Moreover, radiofrequency transistors, with as-measured cut-off frequency fT and maximum oscillation frequency fmax both >10 GHz, have been demonstrated. The unique wide bandgap and low dielectric constant of ITO provide prospects for future scaling below the 5-nm regime for advanced low-power electronics.

Scalable high performance radio frequency electronics based on large domain bilayer MoS2.

Atomically-thin layered molybdenum disulfide (MoS2) has attracted tremendous research attention for their potential applications in high performance DC and radio frequency electronics, especially for flexible electronics. Bilayer MoS2 is expected to have higher electron mobility and higher density of states with higher performance compared with single layer MoS2. Here, we systematically investigate the synthesis of high quality bilayer MoS2 by chemical vapor deposition on molten glass with increasing domain sizes up to 200 µm. High performance transistors with optimized high-κ dielectrics deliver ON-current of 427 µA µm-1 at 300 K and a record high ON-current of 1.52 mA µm-1 at 4.3 K. Moreover, radio frequency transistors are demonstrated with an extrinsic high cut-off frequency of 7.2 GHz and record high extrinsic maximum frequency of oscillation of 23 GHz, together with gigahertz MoS2 mixers on flexible polyimide substrate, showing the great potential for future high performance DC and high-frequency electronics.

High-Performance CVD Bernal-Stacked Bilayer Graphene Transistors for Amplifying and Mixing Signals at High Frequencies.

Tunable bandgap can be induced in Bernal-stacked bilayer graphene by a perpendicularly electric displacement field. Here, we carry out a comprehensive study on the material synthesis of CVD Bernal-stacked bilayer graphene and devices for amplifying and mixing at high frequencies. The transistors show large output current density with excellent current saturation with high intrinsic voltage gain up to 77. Positive extrinsic forward power gain | S21|2 has been obtained up to 5.6 GHz as well as high conversion gain of -7 dB for the mixers. The conversion gain dependence on tunable on/off ratio of the transistors has also been discussed.

Effects of Nitrogen and Hydrogen Codoping on the Electrical Performance and Reliability of InGaZnO Thin-Film Transistors.

Despite intensive research on improvement in electrical performances of ZnO-based thin-film transistors (TFTs), the instability issues have limited their applications for complementary electronics. Herein, we have investigated the effect of nitrogen and hydrogen (N/H) codoping on the electrical performance and reliability of amorphous InGaZnO (α-IGZO) TFTs. The performance and bias stress stability of α-IGZO device were simultaneously improved by N/H plasma treatment with a high field-effect mobility of 45.3 cm2/(V s) and small shifts of threshold voltage (Vth). On the basis of X-ray photoelectron spectroscopy analysis, the improved electrical performances of α-IGZO TFT should be attributed to the appropriate amount of N/H codoping, which could not only control the Vth and carrier concentration efficiently, but also passivate the defects such as oxygen vacancy due to the formation of stable Zn-N and N-H bonds. Meanwhile, low-frequency noise analysis indicates that the average trap density near the α-IGZO/SiO2 interface is reduced by the nitrogen and hydrogen plasma treatment. This method could provide a step toward the development of α-IGZO TFTs for potential applications in next-generation high-definition optoelectronic displays.

Regulation of pqs quorum sensing via catabolite repression control in Pseudomonas aeruginosa.

Bacteria have evolved a set of regulatory pathways to adapt to the dynamic nutritional environment during the course of infection. However, the underlying mechanism of the regulatory effects by nutritional cues on bacterial pathogenesis is unclear. In the present study, we showed that the Pseudomonas aeruginosa catabolite repression control protein regulates the Pseudomonas quinolone signal quorum sensing, which further controls synthesis of virulence factor pyocyanin, biofilm formation and survival during infection models. Our study suggests that deregulation of the catabolite repression by P. aeruginosa might enhance its fitness during cystic fibrosis infections.

The catabolite repression control protein Crc plays a role in the development of antimicrobial-tolerant subpopulations in Pseudomonas aeruginosa biofilms.

Bacteria form complex surface-attached biofilm communities in nature. Biofilm cells differentiate into subpopulations which display tolerance towards antimicrobial agents. However, the signal transduction pathways regulating subpopulation differentiation in biofilms are largely unelucidated. In the present study, we show that the catabolite repression control protein Crc regulates the metabolic state of Pseudomonas aeruginosa cells in biofilms, and plays an important role in the development of antimicrobial-tolerant subpopulations in P. aeruginosa biofilms.