TiS2

/Tag: TiS2

Oxidation effect on the shear strength of graphene on aluminum and titanium surfaces

2018-11-13T16:33:54+00:00November 13th, 2018|Categories: Publications|Tags: , |

Author(s): Soumendu Bagchi, Changhong Ke, and Huck Beng ChewWe report the interfacial shear strength of graphene on pure and oxidized Ti and Al metal surfaces using density functional theory calculations. Our results show significant changes to the graphene-metal bonding properties in the presence of an oxide phase. In particular, the strongly chemisorbed in…[Phys. Rev. B 98, 174106] Published Tue Nov 13, 2018

Published in: "Physical Review B".

Ordered Nanotubular Titanium Disulfide (TiS2) Structures: Synthesis and Use as Counter Electrodes in Dye Sensitized Solar Cells (DSSCs)

2018-11-02T14:31:20+00:00November 2nd, 2018|Categories: Publications|Tags: |

TiS2 nanotubular structures were synthesized by a high temperature H2S treatment of anodized TiO2 nanotube layers, and their electrochemical activity for a use as counter electrodes in dye sensitized solar cells (DSSCs) was evaluated. During conversion to TiS2 compositional, morphological and structural transformations were monitored. The fully converted TiS2 nanostructures show a high electrocatalytic activity for the I–/I3– oxidation comparable to a nanoparticular platinum layer. For a simplified model a DSSC solar cell efficiency of 6.1% was obtained using the TiS2 nanotube layer as counter electrode, which is very close to values obtained for a Pt reference (6.2%).

Published in: "Journal of the Electrochemical Society".

Attosecond-resolved petahertz carrier motion in semi-metallic TiS2. (arXiv:1808.06493v1 [cond-mat.mtrl-sci])

2018-08-21T02:29:19+00:00August 21st, 2018|Categories: Publications|Tags: , |

Knowledge about the real-time response of carriers to optical fields in solids is paramount to advance information processing towards optical frequencies or to understand the bottlenecks of light-matter interaction and energy harvesting. Of particular importance are semi-metals and transition metal dichalcogenides due to their small band gap and high carrier mobility. Here, we examine the opto-electronic response of TiS2 to optical excitation by means of attosecond soft x-ray spectroscopy at the L-edges of Ti at 460 eV. Using weak-field infrared single-photon excitation, we examine conditions that avoid excessive excitation, but still attain efficient injection of 0.2% of valence band carriers into the lowest lying conduction band. We demonstrate that the efficient injection and the high- carrier mobility of the conduction band permits leveraging the material to achieve petahertz-speed opto-electronic control of its carriers. Our results are an important step towards understanding the dynamics of carriers and their control under field conditions that are realistic for device implementation in semi-metallic layered materials, thus they may lead to ultrafast and optically controlled field-effect devices and sensors.

Published in: "arXiv Material Science".

Ultrafast Saturable Absorption in TiS2 Induced by Non-Equilibrium Electrons and Generation of Femtosecond Mode-Locked Laser

2018-04-30T14:24:24+00:00April 30th, 2018|Categories: Publications|Tags: , |

Nanoscale, 2018, Accepted ManuscriptDOI: 10.1039/C8NR01573B, PaperXiangling Tian, Rongfei Wei, Meng Liu, Chunhui Zhu, Zhichao Luo, Fengqiu Wang, Jianrong QiuAbstract: Non-equilibrium electrons induced by ultrafast laser excitation in a correlated electron material can disturb the Fermi energy as well as optical nonlinearity. Here, non-equilibrium

Published in: "RSC Nanoscale".

A low-temperature and facile solution-processed two-dimensional TiS2 as an effective electron transport layer for UV-stable planar perovskite solar cell

2018-04-13T11:17:59+00:00April 13th, 2018|Categories: Publications|Tags: |

J. Mater. Chem. A, 2018, Accepted ManuscriptDOI: 10.1039/C8TA01143E, PaperGuannan Yin, Huan Zhao, Jiangshan Feng, Jie Sun, Junqing Yan, Zhike Liu, Shenghuang LIN, Shengzhong LiuThe charge transport layers (CTLs) play a great role in achieving high efficient and stable perovskite solar cells (PSCs). Recently,

Published in: "Journal of Materials Chemistry A".

Solution-printable fullerene/TiS2 organic/inorganic hybrids for high-performance flexible n-type thermoelectrics

2018-03-27T08:28:23+00:00March 27th, 2018|Categories: Uncategorized|Tags: , |

Energy Environ. Sci., 2018, Advance ArticleDOI: 10.1039/C7EE03617E, PaperLiming Wang, Zimeng Zhang, Linxiao Geng, Tianyu Yuan, Yuchen Liu, Juchen Guo, Lei Fang, Jingjing Qiu, Shiren WangFlexible and solution-printable fullerene/TiS2 organic/inorganic hybrids with excellent thermoelectric properties are demonstrated.To cite this article before page numbers are assigned, use the DOI form of citation above.The content of this RSS Feed (c) The Royal Society of Chemistry

Published in: "Energy & Environmental Science".

Two-dimensional transition metal dichalcogenides as metal source of metal-organic frameworks

2018-03-20T14:31:05+00:00March 20th, 2018|Categories: Publications|Tags: |

Chem. Commun., 2018, Accepted ManuscriptDOI: 10.1039/C8CC01258J, CommunicationYanwei Sun, Shen Hu, Chunshan Song, Shu Miao, Zhou Jiang, Xue Jiang, Jijun Zhao, Xinwen Guo, Yi LiuBy taking advantage of the layered structure and decent M-X bond strength of transition metal dichalcogenides (TMDCs), herein versatile Ti-MOFs were successfully prepared with layered titanium disulfide (TiS2) as titanium…The content of this RSS Feed (c) The Royal Society of Chemistry

Published in: "Chemical Communications".

Titanium contacts to graphene: process-induced variability in electronic and thermal transport

2018-02-16T10:30:35+00:00February 16th, 2018|Categories: Publications|Tags: , |

Contact resistance ( R C ) is a major limiting factor in the performance of graphene devices. R C is sensitive to the quality of the interface and the composition of the contact, which are affected by the graphene transfer process and contact deposition conditions. In this work, a linear correlation is observed between the composition of Ti contacts, characterized by x-ray photoelectron spectroscopy, and the Ti/graphene contact resistance measured by the transfer length method. We find that contact composition is tunable via deposition rate and base pressure. Reactor base pressure is found to effect the resultant contact resistance. The effect of contact deposition conditions on thermal transport measured by time-domain thermoreflectance is also reported. Interfaces with higher oxide composition appear to result in a lower thermal boundary conductance. Possible origins of this thermal boundary conductance change with oxide composition are discus…

Published in: "Nanotechnology".

Illuminating interlayer interactions

2018-02-12T16:31:04+00:00February 12th, 2018|Categories: Publications|Tags: |

Illuminating interlayer interactionsIlluminating interlayer interactions, Published online: 12 February 2018; doi:10.1038/s41563-018-0027-3A synchrotron X-ray diffraction experiment demonstrates an unexpected accumulation of electron density in the interlayer region of TiS2, and provides a benchmark for theoretical models of weak interlayer bonding.

Published in: "Nature Materials".

X-ray electron density investigation of chemical bonding in van der Waals materials

2018-02-12T16:31:04+00:00February 12th, 2018|Categories: Publications|Tags: |

X-ray electron density investigation of chemical bonding in van der Waals materialsX-ray electron density investigation of chemical bonding in van der Waals materials, Published online: 12 February 2018; doi:10.1038/s41563-017-0012-2Electron density in TiS2 is determined by synchrotron X-ray diffraction, which reveals significant differences between experimental data and theory for interlayer van der Waals interactions.

Published in: "Nature Materials".

A study of electron and thermal transport in layered Titanium disulphide single crystals. (arXiv:1801.04677v1 [cond-mat.mes-hall])

2018-01-16T19:59:07+00:00January 16th, 2018|Categories: Publications|Tags: |

We present a detailed study of thermal and electrical transport behavior of single crystal Titanium disulphide flakes, which belongs to the two dimensional, transition metal dichalcogenide class of materials. In-plane Seebeck effect measurements revealed a typical metal-like linear temperature dependence in the range of 85 – 285 K. Electrical transport measurements with in-plane current geometry exhibited a nearly T^2 dependence of resistivity in the range of 10 – 300 K. However, transport measurements along the out-of-plane current geometry showed a transition in temperature dependence of resistivity from T^2 to T^5 beyond 200 K. Interestingly, Au ion-irradiated TiS2 samples showed a similar T 5 dependence of resistivity beyond 200 K, even in the current-in-plane geometry. Micro- Raman measurements were performed to study the phonon modes in both pristine and ion-irradiated TiS2 crystals.

Published : "arXiv Mesoscale and Nanoscale Physics".

Cryo-mediated exfoliation and fracturing of layered materials into 2D quantum dots

2017-12-15T20:32:19+00:00December 15th, 2017|Categories: Publications|Tags: , , , , |

Atomically thin quantum dots from layered materials promise new science and applications, but their scalable synthesis and separation have been challenging. We demonstrate a universal approach for the preparation of quantum dots from a series of materials, such as graphite, MoS2, WS2, h-BN, TiS2, NbS2, Bi2Se3, MoTe2, Sb2Te3, etc., using

Published in: "Science Advances".

Titanium Disulfide Coated Carbon Nanotube Hybrid Electrodes Enable High Energy Density Symmetric Pseudocapacitors

2017-12-11T16:31:36+00:00December 11th, 2017|Categories: Publications|Tags: , |

Abstract While electrochemical supercapacitors often show high power density and long operation lifetimes, they are plagued by limited energy density. Pseudocapacitive materials, in contrast, operate by fast surface redox reactions and are shown to enhance energy storage of supercapacitors. Furthermore, several reported systems exhibit high capacitance but restricted electrochemical voltage windows, usually no more than 1 V in aqueous electrolytes. Here, it is demonstrated that vertically aligned carbon nanotubes (VACNTs) with uniformly coated, pseudocapacitive titanium disulfide (TiS2) composite electrodes can extend the stable working range to over 3 V to achieve a high capacitance of 195 F g−1 in an Li-rich electrolyte. A symmetric cell demonstrates an energy density of 60.9 Wh kg−1—the highest among symmetric pseudocapacitors using metal oxides, conducting polymers, 2D transition metal carbides (MXene), and other transition metal dichalcogenides. Nanostructures prepared by an atomic layer deposition/sulfurization process facilitate ion transportation and surface reactions to result in a high power density of 1250 W kg−1 with stable operation over 10 000 cycles. A flexible solid-state supercapacitor prepared by transferring the TiS2–VACNT composite film onto Kapton tape is demonstrated to power a 2.2 V light emitting diode (LED) for 1 min. TiS2 is coated coaxially onto vertically aligned carbon nanotubes (VACNTs) via an atomic layer deposition sulfurization process, providing an exceptionally high capacitance of 195 F g-1 and working voltage window up to 3 V in an Li+ ion rich (21 m) electrolyte. The Energy density of a supercapacitor based on TiS2–VACNT electrodes is enhanced to 60.9 Wh kg-1,

Published in: "Advanced Materials".

Metallic 1T-TiS2 nanodots anchored on a 2D graphitic C3N4 nanosheet nanostructure with high electron transfer capability for enhanced photocatalytic performance

2017-12-05T10:29:14+00:00December 5th, 2017|Categories: Publications|Tags: |

RSC Adv., 2017, 7,55269-55275DOI: 10.1039/C7RA10826E, Paper Open Access &nbsp This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.Yang Liu, Xiaojie She, Xiaoni Zhang, Chenglu Liang, Jingjie Wu, Peng Yu, Yusuke Nakanishi, Banghu Xie, Hui Xu, Pulickel[space]M. Ajayan, Wei YangThe introduction

Published in: "RSC Advances".

Titanium Contacts to Graphene: Process-Induced Variability in Electronic and Thermal Transport. (arXiv:1712.00331v1 [cond-mat.mtrl-sci])

2017-12-04T19:58:59+00:00December 4th, 2017|Categories: Publications|Tags: , |

Contact Resistance (RC) is a major limiting factor in the performance of graphene devices. RC is sensitive to the quality of the interface and the composition of the contact, which are affected by the graphene transfer process and contact deposition conditions. In this work, a linear correlation is observed between the composition of Ti contacts, characterized by X-ray photoelectron spectroscopy, and the Ti/graphene (Gr) contact resistance measured by the transfer length method. We find that contact composition is tunable via deposition rate and base pressure. Reactor base pressure is found to effect the resultant contact resistance. The effect of contact deposition conditions on thermal transport measured by time-domain thermoreflectance is also reported and interfaces with higher oxide composition appear to result in a lower thermal boundary conductance. Possible origins of this thermal boundary conductance change with oxide composition are discussed.

Published in: "arXiv Material Science".

Improved Biocompatibility of Black Phosphorus Nanosheets by Chemical Modification

2017-10-13T20:26:50+00:00October 13th, 2017|Categories: Publications|Tags: , |

Ultrasmall black phosphorus nanosheets (BPs) can trigger systemic inflammations. In their Communication (DOI: 10.1002/anie.201706228) X.-F. Yu, G. Jiang et al. report a method to reduce this side effect by surface modification of bare BPs with titanium sulfate ([email protected]). The girl represents a potential candidate exposed to bare BPs through various routes during a wide application of this material. The effect of the bare BPs is shown by red shading. The BPs are less harmful after conversion to [email protected]

Published in: "Angewandte Chemie International Edition".

Palladium Nanoparticles Anchored on Anatase Titanium Dioxide-Black Phosphorus Hybrids with Heterointerfaces: Highly Electroactive and Durable Catalysts for Ethanol Electrooxidation

2017-10-04T08:28:56+00:00October 4th, 2017|Categories: Publications|Tags: , |

Abstract Designing high-performance palladium (Pd) supports with enhanced ethanol oxidation reaction (EOR) activity has consistently been a challenge. Here, a novel anatase titanium dioxide nanosheets-black phosphorus (ATN-BP) hybrid is fabricated as a support for Pd nanoparticles used in the EOR. The direct ball-milling of BP nanoflakes and ATN under argon protection lead to the formation of ATN-BP hybrids with BP nanoflakes interconnected by cataclastic ATN with POTi bonds. The structure of ATN-BP not only is beneficial for improving the electrolyte penetration and electron transportation but also has a strong influence on the stripping of reactive intermediates through the synergistic interaction between Pd and ATN-BP. The results demonstrate that the Pd/ATN-BP hybrids with heterointerfaces of Pd, BP, and ATN exhibit ultrahigh electroactivity and durability. In the EOR, the Pd/ATN-BP catalyst can achieve an electrochemically active surface area of ≈462.1 m2 gPd−1 and a mass peak current density of 5023.8 mA mgPd−1, which are 11.67 and 6.87 times greater, respectively, than those of commercial Pd/C. The Pd/ATN-BP catalysts also show remarkable stability with a retention rate of the peak current density of ≈30.6% after a durability test of 3600 s. Ultrahigh-performance ethanol electrooxidation: The combination of anatase titanium dioxide nanosheets (ATN) with black phosphorus (BP) is used to support palladium (Pd) nanoparticles. The Pd/ATN-BP catalyst exhibits super high electrochemical active surface area (462.1 m2 gPd−1) and mass peak current density (5023.8 mA mgPd−1) for ethanol electrooxidation, which are 11.67 and 6.87 times higher, respectively, than those of commercial Pd/Carbon.

Published in: "Advanced Energy Materials".

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