Over the past few decades, two-dimensional (2D) and layered materials have emerged as new fields. Due to the zero-band-gap nature of graphene and the low photocatalytic performance of MoS2, more ...advanced semiconducting 2D materials have been prompted. As a result, semiconductor black phosphorus (BP) is a derived cutting-edge post-graphene contender for nanoelectrical application, because of its direct-band-gap nature. For the first time, we report on robust BP@TiO2 hybrid photocatalysts offering enhanced photocatalytic performance under light irradiation in environmental and biomedical fields, with negligible affected on temperature and pH conditions, as compared with MoS2@TiO2 prepared by the identical synthesis method. Remarkably, in contrast to pure few layered BP, which, due to its intrinsic sensitivity to oxygen and humidity was readily dissolved after just several uses, the BP@TiO2 hybrid photocatalysts showed a ~92% photocatalytic activity after 15 runs. Thus, metal-oxide-stabilized BP photocatalysts can be practically applied as a promising alternative to graphene and MoS2.
The surface morphology of copper (Cu) often changes after the synthesis of graphene by chemical vapor deposition (CVD) on a Cu foil, which affects the electrical properties of graphene, as the Cu ...step bunches induce the periodic ripples on graphene that significantly disturb electrical conduction. However, the origin of the Cu surface reconstruction has not been completely understood yet. Here, we show that the compressive strain on graphene induced by the mismatch of thermal expansion coefficient with Cu surface can be released by forming periodic Cu step bunching that depends on graphene layers. Atomic force microscopy (AFM) images and the Raman analysis show the noticeably longer and higher step bunching of Cu surface under multilayer graphene and the weaker biaxial compressive strain on multilayer graphene compared to monolayer. We found that the surface areas of Cu step bunches under multilayer and monolayer graphene are increased by ∼1.41% and ∼0.77% compared to a flat surface, respectively, indicating that the compressive strain on multilayer graphene can be more effectively released by forming the Cu step bunching with larger area and longer periodicity. We believe that our finding on the strain relaxation of graphene layers by Cu step bunching formation would provide a crucial idea to enhance the electrical performance of graphene electrodes by controlling the ripple density of graphene.
A facile methodology for the large‐scale production of layer‐controlled MoS2 layers on an inexpensive substrate involving a simple coating of single source precursor with subsequent ...roll‐to‐roll‐based thermal decomposition is developed. The resulting 50 cm long MoS2 layers synthesized on Ni foils possess excellent long‐range uniformity and optimum stoichiometry. Moreover, this methodology is promising because it enables simple control of the number of MoS2 layers by simply adjusting the concentration of (NH4)2MoS4. Additionally, the capability of the MoS2 for practical applications in electronic/optoelectronic devices and catalysts for hydrogen evolution reaction is verified. The MoS2‐based field effect transistors exhibit unipolar n‐channel transistor behavior with electron mobility of 0.6 cm2 V−1 s−1 and an on‐off ratio of ≈10³. The MoS2‐based visible‐light photodetectors are fabricated in order to evaluate their photoelectrical properties, obtaining an 100% yield for active devices with significant photocurrents and extracted photoresponsivity of ≈22 mA W−1. Moreover, the MoS2 layers on Ni foils exhibit applicable catalytic activity with observed overpotential of ≈165 mV and a Tafel slope of 133 mV dec−1. Based on these results, it is envisaged that the cost‐effective methodology will trigger actual industrial applications, as well as novel research related to 2D semiconductor‐based multifaceted applications.
A facile methodology for the large‐scale production of layer‐controlled MoS2 layers on an inexpensive substrate implemented with subsequent two‐step roll‐to‐roll‐based thermal decomposition is developed. The resulting 50 cm long MoS2 layers synthesized on Ni foils possess excellent long‐range uniformity. This methodology is a promising way for simple control of the number of MoS2 layers by adjusting the concentration of (NH4)2MoS4.
Novel functional materials that use both the spin and charge of an electron offer many exciting opportunities to create new information processing and storage devices with ultralow power consumption. ...The recent discovery of magnetism in atomically thin-layered materials could boost research in the field of light element materials such as van der Waals magnetic nanostructures. Here, we report intrinsic magnetization in large-area graphene grown on Fe(100) foil structures. The optimal growth mechanisms provide high-quality graphene samples with controllable magnetic properties, such as thickness-dependent magnetization. Using first-principles calculations, we investigated several possible scenarios for controlling the magnetic properties. Moreover, the independent magnetic structures induced in graphene were identified through field-applied magnetic force microscopy (FA-MFM) followed by vibrating sample magnetometry (VSM). Our results open a new avenue for controlling the magnetic properties of graphene structures by mediating surface growth on regular magnets for applications in large-scale spintronics.
Sexual dysfunction is a common condition in patients taking antipsychotics, and is the most bothersome symptom and adverse drug effect, resulting in a negative effect on treatment compliance. It is ...known that hyperprolactinemia is a major cause of sexual dysfunction. Based on the blockade of dopamine D2 receptors, haloperidol, risperidone, and amisulpride are classed as prolactin-elevating antipsychotics, while olanzapine, clozapine, quetiapine, ziprasidone, and aripiprazole are classed as prolactin-sparing drugs. Risperidone and the other typical antipsychotics are associated with a high rate of sexual dysfunction as compared to olanzapine, clozapine, quetiapine, and aripiprazole. With regard to treatment in patients suffering from sexual dysfunction, sildenafil was associated with significantly more erections sufficient for penetration as compared to a placebo. Subsequent studies are needed in order to provide physicians with a better understanding of this problem, thereby leading toward efficacious and safe solutions.
Laparoscopic subtotal cholecystectomy (LSC) can be an alternative surgical technique for difficult cholecystectomies. Surgeons performing LSC sometimes leave the posterior wall of the gallbladder ...(GB) to shorten the operation time and avoid liver injury. However, leaving the inflamed posterior GB wall is a major concern. In this study, we evaluated the clinical outcomes of standard laparoscopic cholecystectomy (SLC), LSC, and LSC removing only anterior wall of the GB (LSCA).
We retrospectively reviewed the medical records of laparoscopic cholecystectomies performed between January 2006 to December 2015 and analyzed the outcomes of SLC, LSC, and LSCA.
A total of 1,037 patients underwent SLC. 22 patients underwent LSC; and 27 patients underwent LSCA. The mean operating times of SLC, LSC, and LSCA were 41, 74, and 68 minutes, respectively (P < 0.01). Blood loss was 5, 45, and 33 mL (P < 0.05). The mean lengths of postoperative hospitalization were 3.4, 5.4, and 5.8 days. Complications occurred in 24 SLC patients (2.3%), 2 LSC patients (9%), and 1 LSCA patient (3.7%). There was no mortality among the LSC and LSCA patients.
LSC and LSCA are safe and feasible alternatives for difficult cholecystectomies. These procedures help surgeons avoid bile duct injury and conversion to laparotomy. LSCA has the benefits of shorter operation time and less bleeding compared to LSC.
Here we provide evidence of two selective growth modes, namely the ‘surface adsorption (SA) mode’ and the ‘diffusion and precipitation (DP) mode’ for the synthesis of graphene on Cu foil by thermal ...chemical vapor deposition. Using acetylene feedstock, the number of graphene layers was controlled simply by adjusting the injection time, and the DP growth mode was clearly verified by the existence of a carbon-diffused Cu layer with expansion of the Cu lattice. With methane feedstock, either SA or DP growth modes could be selected for the growth of graphene at low or high partial pressure of carbon feedstocks, respectively. The critical pressure for switching the growth modes depends on reactivity of carbon feedstock to Cu substrate.
The band-gap opening in graphene is a key factor in developing graphene-based field-effect transistors. Although graphene is a gapless semimetal, a band gap opens when graphene is formed into a ...graphene nanoribbon (GNR). Moreover, the band-gap energy can be manipulated by the width of the GNR. In this study, we propose a site-specific synthesis of a width-tailored GNR directly onto an insulating substrate. Predeposition of a diamond-like carbon nanotemplate onto a SiO2/Si wafer via focused ion-beam-assisted chemical vapor deposition is first utilized for growth of the GNR. These results may present a feasible route for growing a width-tailored GNR onto a specific region of an insulating substrate.
•Boron and nitrogen co-doping of diamond-like carbon (DLC) film by vaporizing borane ammonia was demonstrated.•The simultaneous occurrence of graphitization and co-doping of DLC film can affect the ...improvement in the electrical properties.•The sheet resistance and optical transmittance of the doped DLC with a thickness of 28.5nm were 3.53±0.19kΩ/sq and ∼81.25%, respectively.
We demonstrate boron and nitrogen co-doping of diamond-like carbon (DLC) film by vaporizing borane ammonia for applications in anti-scratch and extremely robust transparent conductive films. This method allows for facile fabrication of boron and nitrogen co-doped DLC (BNDLC) film with ultra-flat surface and uniform thickness. The simultaneous occurrence of graphitization and boron and nitrogen co-doping of DLC film induced by increasing the co-doping temperature was observed and lead to a significant decrease in the sheet resistance. As a result, the sheet resistance and optical transmittance at 550nm of the BNDLC were 3.53±0.19kΩ/sq and 81.25%, respectively.
In-situ X-ray photoemission spectroscopy (XPS) has been used to investigate the initial stages of TiO 2 growth on a Si(001) substrate by atomic layer deposition (ALD). The core level spectra of Si ...2p, C 1s, O 1s, and Ti 2p were measured at every half reaction in the titanium tetra-isopropoxide (TTIP)--H 2 O ALD process. The ligand exchange reactions were verified using the periodic oscillation of the C 1s concentration, as well as changes in the hydroxyl concentration. XPS analysis revealed that Ti 2 O 3 and Si oxide were formed at the initial stages of TiO 2 growth. A stoichiometric TiO 2 layer was dominantly formed after two cycles and was chemically saturated after four cycles.
PDF
