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Worasak Rotjanapittayakul, Wanchai Pijitrojana, Thomas Archer, Stefano Sanvito, Jariyanee Prasongkit
Recently magnetic tunnel junctions using two-dimensional MoS2 as nonmagnetic spacer have been fabricated, although their magnetoresistance has been reported to be quite low. This may be attributed to the use of permalloy electrodes, injecting current with a relatively small spin polarization. Here we evaluate the performance of MoS2 -based tunnel junctions using Fe3 Si Heusler alloy electrodes. Density functional theory and the non-equilibrium Green's function method are used to investigate the spin injection efficiency (SIE) and the magnetoresistance (MR) ratio as a function of the MoS2 thickness...
March 19, 2018: Scientific Reports
Hongliang Li, Liangbing Wang, Yizhou Dai, Zhengtian Pu, Zhuohan Lao, Yawei Chen, Menglin Wang, Xusheng Zheng, Junfa Zhu, Wenhua Zhang, Rui Si, Chao Ma, Jie Zeng
Exploring the interaction between two neighbouring monomers has great potential to significantly raise the performance and deepen the mechanistic understanding of heterogeneous catalysis. Herein, we demonstrate that the synergetic interaction between neighbouring Pt monomers on MoS2 greatly enhanced the CO2 hydrogenation catalytic activity and reduced the activation energy relative to isolated monomers. Neighbouring Pt monomers were achieved by increasing the Pt mass loading up to 7.5% while maintaining the atomic dispersion of Pt...
March 19, 2018: Nature Nanotechnology
Julien Chaste, Amine Missaoui, Si Huang, Hugo Henck, Zeineb Ben Aziza, Laurence Ferlazzo, Adrian Balan, Alan T Charlie Johnson, Rémy Braive, Abdelkarim Ouerghi
Semiconducting 2D materials, such as transition metal dichalcogenides (TMDs), are emerging in nanomechanics, optoelectronics, and thermal transport. In each of these fields, perfect control over 2D material properties including strain, doping, and heating is necessary, especially on the nanoscale. Here, we study clean devices consisting of membranes of single-layer MoS2 suspended on pillar arrays. Using Raman and photoluminescence spectroscopy, we have been able to extract, separate and simulate the different contributions on the nanoscale and to correlate these to the pillar array design...
March 19, 2018: ACS Nano
Yanfeng Wang, Wei Chen, Xiao Chen, Huajun Feng, Dongsheng Shen, Bin Huang, Yufeng Jia, Yuyang Zhou, Yuxiang Liang
CdS/MoS2 , an extremely efficient photocatalyst, has been extensively used in hydrogen photoproduction and pollutant degradation. CdS/MoS2 can be synthesized by a facile one-step hydrothermal process. However, the effect of the sulfur source on the synthesis of CdS/MoS2 via one-step hydrothermal methods has seldom been investigated. We report herein a series of one-step hydrothermal preparations of CdS/MoS2 using three different sulfur sources: thioacetamide, l-cysteine, and thiourea. The results revealed that the sulfur source strongly affected the crystallization, morphology, elemental composition and ultraviolet (UV)-visible-light-absorption ability of the CdS/MoS2 ...
March 2018: Journal of Environmental Sciences (China)
Berc Kalanyan, William A Kimes, Ryan Beams, Stephan J Stranick, Elias Garratt, Irina Kalish, Albert V Davydov, Ravindra K Kanjolia, James E Maslar
High volume manufacturing of devices based on transition metal dichalcogenide (TMD) ultra-thin films will require deposition techniques that are capable of reproducible wafer-scale growth with monolayer control. To date, TMD growth efforts have largely relied upon sublimation and transport of solid precursors with minimal control over vapor phase flux and gas-phase chemistry, which are critical for scaling up laboratory processes to manufacturing settings. To address these issues, we report a new pulsed metalorganic chemical vapor deposition (MOCVD) route for MoS2 film growth in a research-grade single-wafer reactor...
August 8, 2017: Chemistry of Materials: a Publication of the American Chemical Society
Zhi Chen, Dangui Yin, Ming Zhang
Sandwich-like MoS2 @SnO2 @C nanosheeets are prepared by facile hydrothermal reactions. SnO2 nanosheets can attach to exfoliated MoS2 nanosheets to prevent restacking of adjacent MoS2 nanosheets, and carbon transformed from polyvinylpyrrolidone is coated on MoS2 @SnO2 , forming a sandwich structure to maintain cycling stability. As an anode for sodium-ion batteries, the electrode greatly deliverers a high initial discharge specific capacity of 530 mA h g-1 and maintains at 396 mA h g-1 after 150 cycles at 0...
March 15, 2018: Small
Yaowu Hu, Feng Zhang, Michael Titze, Biwei Deng, Hebin Li, Gary J Cheng
Strain-engineering of two-dimensional (2D) transition metal dichalcogenides (TMDs) has great potential to alter their electronic and optical properties. Thus far, experimental studies of the straining effects in 2D TMDs primarily focused on the static property measurements at room temperature. However, low-temperature and temperature-dependence studies are essential in understanding the underlying mechanisms of the unique properties of monolayer TMDs. Herein, the temperature-dependent dynamic properties of laser shock strain-engineered monolayer MoS2 were studied using temperature-dependent photoluminescence (PL) and pump-probe spectroscopy...
March 14, 2018: Nanoscale
Qiyi Fang, Qiu Yu Shang, Liyun Zhao, Rui Wang, Zhepeng Zhang, Pengfei Yang, Xinyu Sui, Xiaohui Qiu, Xinfeng Liu, Qing Zhang, Yanfeng Zhang
Mixed-dimensional van der Walls heterostructures between one dimensional (1D) perovskite nanowires and two dimensional (2D) transition metal dichalcogenides (TMDCs) hold great potentials for novel optoelectronics and light harvesting applications. However, the ultrafast carrier dynamics between the 1D perovskite and 2D TMDCs is currently not well understood, which is critical for related optoelectronic applications. Here we demonstrate van der Walls heterostructures of CsPbBr3 nanowire/monolayer-MoS2 and CsPbBr3/monolayer-WSe2 and further present systematic investigation on their charge transfer dynamics...
March 13, 2018: Journal of Physical Chemistry Letters
Neema Pallikkarathodi Mani, Manjunatha Ganiga, Jobin Cyriac
Fluorescence sensors for biologically active molecules are catching attention due to their good performance and simplicity. Herein, we report a fluorescence sensor for the selective and sensitive detection of dopamine (DA) in aqueous samples. MoS2 nanohybrid material composed of MoS2 quantum dots dispersed over MoS2 nanosheets (MoS2 QDNS) in alkaline medium was employed as the fluorescent probe. In the presence of DA, the photoluminescence intensity of MoS2 QDNS was quenched linearly with increasing concentration of the former...
March 13, 2018: Analyst
Jyun-Hong Chen, Yuan-Liang Zhong, Lain-Jong Li, Chii-Dong Chen
Two-dimensional electron gas (2DEG) is crucial in condensed matter physics and is present on the surface of liquid helium and at the interface of semiconductors. Monolayer MoS2 of 2D materials also contains 2DEG in an atomic layer as field effect transistor (FET) ultrathin channel. In this study, we synthesized double triangular MoS<sub>2</sub> through a chemical vapor deposition method to obtain grain boundaries for forming a ripple structure in FET channel. When the temperature was higher than approximately 175 K, the temperature dependence of the electron mobility μ was consistent with those in previous experiments and theoretical predictions...
March 12, 2018: Nanotechnology
Wenzhuo Wu, Cong Wei, Xiangcheng Lin, Qun Xu
As a promising non-precious metal photoelectrochemical (PEC) catalyst, MoS2 exhibits high electrocatalytic activity and stability, while the weak light absorption efficiency and low photoresponse current limit its practical application. Herein, a facile coassembly approach was proposed to construct the porphyrin-MoS2 composite photoelectrocatalysts. The as-prepared photoelectro-catalysts show significantly enhanced photocurrent response as high as 16 μA cm-2, which is about 2 times higher than that of bare MoS2...
March 12, 2018: Chemistry, An Asian Journal
Maryam Barzegar, Masoud Berahman, Azam Iraji Zad
Recent research interest in two-dimensional (2D) materials has led to an emerging new group of materials known as transition metal dichalcogenides (TMDs), which have significant electrical, optical, and transport properties. MoS2 is one of the well-known 2D materials in this group, which is a semiconductor with controllable band gap based on its structure. The hydrothermal process is known as one of the scalable methods to synthesize MoS2 nanostructures. In this study, the gas sensing properties of flower-shaped MoS2 nanoflakes, which were prepared from molybdenum trioxide (MoO3 ) by a facile hydrothermal method, have been studied...
2018: Beilstein Journal of Nanotechnology
Haiyan Wang, Huanshun Yin, Hua Huang, Kelin Li, Yunlei Zhou, Geoffrey I N Waterhouse, Hai Lin, Shiyun Ai
Herein, a novel dual-signal amplified photoelectrochemical (PEC) biosensor was successfully developed for the highly selective detection of N6 -methyladenosine (m6 A) methylated RNA. The PEC biosensor comprised BiVO4 -110-TiO2 heterojunction and gold nanoparticle decorated MoS2 (MoS2 -AuNPs) as the photoactive materials, horseradish peroxidase conjugated biotin (HRP-Biotin) as the enzymatic unit, Ag+ -mediated cytosine pairs (C-Ag+ -C) as the signal amplification unit, and the anti-m6 A antibody as the m6 A methylated RNA recognition unit...
February 27, 2018: Biosensors & Bioelectronics
Ehsanur Rahman, Abir Shadman, Imtiaz Ahmed, Saeed-Uz-Zaman Khan, Quazi D M Khosru
In this work, a compact transport model has been developed for monolayer transition metal dichalcogenide channel MOSFET. The analytical model solves the Poisson's equation for the inversion charge density to get the electrostatic potential in the channel. Current is then calculated by solving the drift-diffusion equation. The model makes gradual channel approximation to simplify the solution procedure. The appropriate density of states obtained from the first principle DFT simulation has been considered to keep the model physically accurate for monolayer transition metal dichalcogenide channel FET...
March 9, 2018: Nanotechnology
Nina Fu, Yue Hu, Saihua Shi, Shaokang Ren, Wei Liu, Shao Su, Baomin Zhao, Lixing Weng, Lianhui Wang
MiRNAs are small regulatory RNAs that play crucial roles in the oncogenic state in various cancers and have shown highly promising clinical applications as plasma-based markers for cancer classification and prognostication. Due to their electroanalytical advantages, photoelectrochemical biosensors are a very attractive alternative technology for miRNA sensing and detection. In this work, we demonstrated a novel photoelectrochemical (PEC) sensor using the in situ grown Au nanoparticles/two-dimensional molybdenum disulfide (MoS2 ) nanosheet heterojunction (MoS2 -AuNPs) on ITO glass as the photoanode (MoS2 -AuNPs/ITO)...
March 8, 2018: Analyst
Guiyang Zhang, Qiaobo Liao, Yanfeng Liu, Li Wang, Huilin Gou, Can Ke, Xin Huang, Kai Xi, Xudong Jia
The fabrication of reactive aggregation nanomaterials through assemblies in a facile and cost-effective manner is much desired but remains to be well explored. Here we show that exquisite and ultra-long (>2 μm) hybrid polymer nanorods (NRs) can be formed by a simple self-assembly of a phenylboronic acid modified genistein crosslinker (Ge-di(HMPBA-pin)) and d-α-tocopheryl polyethylene glycol 1000 (TPGS). The obtained NRs exhibit quantitative and sensitive colorimetric detection of H2 O2 with a remarkable detection limit for different stromal materials...
March 7, 2018: Nanoscale
Jakub Jadwiszczak, Colin O'Callaghan, Yangbo Zhou, Daniel S Fox, Eamonn Weitz, Darragh Keane, Conor P Cullen, Ian O'Reilly, Clive Downing, Aleksey Shmeliov, Pierce Maguire, John J Gough, Cormac McGuinness, Mauro S Ferreira, A Louise Bradley, John J Boland, Georg S Duesberg, Valeria Nicolosi, Hongzhou Zhang
Precise tunability of electronic properties of two-dimensional (2D) nanomaterials is a key goal of current research in this field of materials science. Chemical modification of layered transition metal dichalcogenides leads to the creation of heterostructures of low-dimensional variants of these materials. In particular, the effect of oxygen-containing plasma treatment on molybdenum disulfide (MoS2 ) has long been thought to be detrimental to the electrical performance of the material. We show that the mobility and conductivity of MoS2 can be precisely controlled and improved by systematic exposure to oxygen/argon plasma and characterize the material using advanced spectroscopy and microscopy...
March 2018: Science Advances
Girma Selale Geleta, Zhen Zhao, Zhenxin Wang
In this study, we developed a novel reduced graphene oxide/molybdenum disulfide/polyaniline@gold nanoparticles-based electrochemical aptasensor (termed as RGO/MoS2 /PANI@AuNPs/Apt) for detection of aflatoxin B1 (AFB1 ). The RGO/MoS2 /PANI nanocomposites were synthesized and characterized by multiple techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (FTIR), UV-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). A glassy carbon electrode (GCE) was then modified by the RGO/MoS2 /PANI nanocomposites, coated with a chitosan (Cs) film, and followed by AuNPs attachment for immobilizing the AFB1 aptamers...
March 6, 2018: Analyst
Xinyi Chia, Nur Ayu Afira Sutrisnoh, Martin Pumera
Platinum (Pt)-based materials are inevitably among the best-performing electrocatalysts for hydrogen evolution reaction (HER). MoS2 was suggested to be a potent HER catalyst to replace Pt in this reaction by theoretical modeling; however, in practice, this dream remains elusive. Here we show a facile one-pot bottom-up synthesis of Pt-MoSx composites using electrochemical reduction in an electrolytic bath of Pt precursor and ammonium tetrathiomolybdate under ambient conditions. By modifying the millimolar concentration of Pt precursors, composites of different surface elemental composition are fabricated; specifically, Pt1...
March 5, 2018: ACS Applied Materials & Interfaces
Minh Dao Tran, Ji-Hee Kim, Hyun Kim, Manh-Ha Doan, Dinh Loc Duong, Young Hee Lee
Because of strong Coulomb interaction in two-dimensional van der Waals layered materials, the trap charges at the interface strongly influence the scattering of the majority carriers, and thus often degrade their electrical properties. However, the photogenerated minority carriers can be trapped at the interface, modulate the electron-hole recombination, and eventually influence the optical properties. In this study, we report the role of the hole trap sites on the inconsistency in the electrical and optical phenomena between two systems with different interfacial trap densities, which are monolayer MoS2 -based field-effect-transistors on hexagonal boron nitride (h-BN) and SiO2 substrates...
March 5, 2018: ACS Applied Materials & Interfaces
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