scholarly journals Creating self-assembled arrays of mono-oxo (MoO3)1 species on TiO2(101) via deposition and decomposition of (MoO3)n oligomers

2021 ◽  
Vol 118 (4) ◽  
pp. e2017703118
Author(s):  
Nassar Doudin ◽  
Greg Collinge ◽  
Pradeep Kumar Gurunathan ◽  
Mal-Soon Lee ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Self Assembly ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Surface Acting ◽  
Dynamic Coupling ◽  
Design And Synthesis ◽  
Ordered Arrays ◽  
Defect Sites ◽  
Saturation Coverage ◽  
Resolution Imaging

Hierarchically ordered oxides are of critical importance in material science and catalysis. Unfortunately, the design and synthesis of such systems remains a key challenge to realizing their potential. In this study, we demonstrate how the deposition of small oligomeric (MoO3)1–6 clusters—formed by the facile sublimation of MoO3 powders—leads to the self-assembly of locally ordered arrays of immobilized mono-oxo (MoO3)1 species on anatase TiO2(101). Using both high-resolution imaging and theoretical calculations, we reveal the dynamic behavior of the oligomers as they spontaneously decompose at room temperature, with the TiO2 surface acting as a template for the growth of this hierarchically structured oxide. Transient mobility of the oligomers on both bare and (MoO3)1-covered TiO2(101) areas is identified as key to the formation of a complete (MoO3)1 overlayer with a saturation coverage of one (MoO3)1 per two undercoordinated surface Ti sites. Simulations reveal a dynamic coupling of the reaction steps to the TiO2 lattice fluctuations, the absence of which kinetically prevents decomposition. Further experimental and theoretical characterizations demonstrate that (MoO3)1 within this material are thermally stable up to 500 K and remain chemically identical with a single empty gap state produced within the TiO2 band structure. Finally, we see that the constituent (MoO3)1 of this material show no proclivity for step and defect sites, suggesting they can reliably be grown on the (101) facet of TiO2 nanoparticles without compromising their chemistry.

scholarly journals Molybdenum Trioxide on Anatase TiO2(101) - Formation of Monodispersed (MoO3)1 Monomers from Oligomeric (MoO3)n Clusters

2020 ◽  
Author(s):  
Nassar Doudin ◽  
Gregory Collinge ◽  
Pradeep Kumar Gurunathan ◽  
Mal Soon Lee ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Molybdenum Trioxide ◽  
Theoretical Calculations ◽  
Complex Oxide ◽  
Oxide Systems ◽  
Design And Synthesis ◽  
Saturation Coverage ◽  
Resolution Imaging ◽  
Complete Layer ◽  
Immense Potential ◽  
Ordered Layers

<p>Complex oxide systems with hierarchical order are of critical importance in material science and catalysis. Despite their immense potential, their design and synthesis are rather difficult. In this study we demonstrate how the deposition of small oligomeric (MoO<sub>3</sub>)<sub>1-6</sub> clusters, which can be formed by the sublimation of MoO<sub>3</sub> powders, leads to the formation of locally ordered layers of (MoO<sub>3</sub>)<sub>1</sub> monomers on anatase TiO<sub>2</sub>(101). Using both high-resolution imaging and theoretical calculations, we show that at room temperature, such oligomers undergo spontaneous dissociation to their monomeric units. In initial stages of the deposition, this is reflected by the observation of one to six neighboring (MoO<sub>3</sub>)<sub>1</sub> monomers that parallel the size distribution of the oligomers. A transient mobility of such oligomers on both bare TiO<sub>2</sub>(101) and (MoO<sub>3</sub>)<sub>1</sub> covered areas is key to the formation of a complete layer with a saturation coverage of one (MoO<sub>3</sub>)<sub>1</sub> per two undercoordinated surface Ti sites. We further show that such layers are stable to 500 K, making them highly suitable for a broad range of applications. </p>

scholarly journals Molybdenum Trioxide on Anatase TiO2(101) - Formation of Monodispersed (MoO3)1 Monomers from Oligomeric (MoO3)n Clusters

2020 ◽  
Author(s):  
Nassar Doudin ◽  
Gregory Collinge ◽  
Pradeep Kumar Gurunathan ◽  
Mal Soon Lee ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Molybdenum Trioxide ◽  
Theoretical Calculations ◽  
Complex Oxide ◽  
Oxide Systems ◽  
Design And Synthesis ◽  
Saturation Coverage ◽  
Resolution Imaging ◽  
Complete Layer ◽  
Immense Potential ◽  
Ordered Layers

<p>Complex oxide systems with hierarchical order are of critical importance in material science and catalysis. Despite their immense potential, their design and synthesis are rather difficult. In this study we demonstrate how the deposition of small oligomeric (MoO<sub>3</sub>)<sub>1-6</sub> clusters, which can be formed by the sublimation of MoO<sub>3</sub> powders, leads to the formation of locally ordered layers of (MoO<sub>3</sub>)<sub>1</sub> monomers on anatase TiO<sub>2</sub>(101). Using both high-resolution imaging and theoretical calculations, we show that at room temperature, such oligomers undergo spontaneous dissociation to their monomeric units. In initial stages of the deposition, this is reflected by the observation of one to six neighboring (MoO<sub>3</sub>)<sub>1</sub> monomers that parallel the size distribution of the oligomers. A transient mobility of such oligomers on both bare TiO<sub>2</sub>(101) and (MoO<sub>3</sub>)<sub>1</sub> covered areas is key to the formation of a complete layer with a saturation coverage of one (MoO<sub>3</sub>)<sub>1</sub> per two undercoordinated surface Ti sites. We further show that such layers are stable to 500 K, making them highly suitable for a broad range of applications. </p>

Molybdenum Trioxide on Anatase TiO2(101) - Formation of Monodispersed (MoO3)1 Monomers from Oligomeric (MoO3)n Clusters

2020 ◽  
Author(s):  
Nassar Doudin ◽  
Gregory Collinge ◽  
Pradeep Kumar Gurunathan ◽  
Mal Soon Lee ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Molybdenum Trioxide ◽  
Theoretical Calculations ◽  
Complex Oxide ◽  
Oxide Systems ◽  
Design And Synthesis ◽  
Saturation Coverage ◽  
Resolution Imaging ◽  
Complete Layer ◽  
Immense Potential ◽  
Ordered Layers

<p>Complex oxide systems with hierarchical order are of critical importance in material science and catalysis. Despite their immense potential, their design and synthesis are rather difficult. In this study we demonstrate how the deposition of small oligomeric (MoO<sub>3</sub>)<sub>1-6</sub> clusters, which can be formed by the sublimation of MoO<sub>3</sub> powders, leads to the formation of locally ordered layers of (MoO<sub>3</sub>)<sub>1</sub> monomers on anatase TiO<sub>2</sub>(101). Using both high-resolution imaging and theoretical calculations, we show that at room temperature, such oligomers undergo spontaneous dissociation to their monomeric units. In initial stages of the deposition, this is reflected by the observation of one to six neighboring (MoO<sub>3</sub>)<sub>1</sub> monomers that parallel the size distribution of the oligomers. A transient mobility of such oligomers on both bare TiO<sub>2</sub>(101) and (MoO<sub>3</sub>)<sub>1</sub> covered areas is key to the formation of a complete layer with a saturation coverage of one (MoO<sub>3</sub>)<sub>1</sub> per two undercoordinated surface Ti sites. We further show that such layers are stable to 500 K, making them highly suitable for a broad range of applications. </p>

Green synthesis of mixed metallic nanoparticles using room temperature self-assembly

2017 ◽  
Vol 13 (2) ◽  
pp. 4671-4677 ◽  
Author(s):  
A. M. Abdelghany ◽  
A.H. Oraby ◽  
Awatif A Hindi ◽  
Doaa M El-Nagar ◽  
Fathia S Alhakami
Keyword(s):  
Self Assembly ◽  
Metallic Nanoparticles ◽  
Room Temperature ◽  
Bimetallic Nanoparticles ◽  
Reduction Process ◽  
Nano Particles ◽  
Nano Structure ◽  
Small Shift ◽  
Molar Ratios ◽  
Vis Spectroscopy

Bimetallic nanoparticles of silver (Ag) and gold (Au) were synthesized at room temperature using Curcumin. Reduction process of silver and gold ions with different molar ratios leads to production of different nanostructures including alloys and core-shells. Produced nanoparticles were characterized simultaneously with FTIR, UV/vis. spectroscopy, transmission electron microscopy (TEM), and Energy-dispersive X-ray (EDAX). UV/vis. optical absorption spectra of as synthesized nanoparticles reveals presence of surface palsmon resonance (SPR) of both silver at (425 nm) and gold at (540 nm) with small shift and broadness of gold band after mixing with resucing and capping agent in natural extract which suggest presence of bimetallic nano structure (Au/Ag). FTIR and EDAX data approve the presence of bimetallic nano structure combined with curcumin extract. TEM micrographs shows that silver and gold can be synthesized separately in the form of nano particles using curcumin extract. Synthesis of gold nano particles in presence of silver effectively enhance and control formation of bi-metallic structure.

scholarly journals A Facile and Efficient Bromination of Multi-Walled Carbon Nanotubes

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3161
Author(s):  
Sandra Zarska ◽  
Damian Kulawik ◽  
Volodymyr Pavlyuk ◽  
Piotr Tomasik ◽  
Alicja Bachmatiuk ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Room Temperature ◽  
Covalent Attachment ◽  
Closed Vessel ◽  
Dangling Bonds ◽  
Magnetic Stirrer ◽  
Defect Sites ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Covalently Bound

The bromination of multi-walled carbon nanotubes (MWCNT) was performed with vapor bromine in a closed vessel, and they were subjected to intensive stirring with a magnetic stirrer for up to 14 days. The efficiency of bromination was compared depending upon duration. The structure and surface of the crude and purified products were characterized by detailed physicochemical analyses, such as SEM/EDS, TEM, XRD, TGA, Raman, and XPS spectroscopies. The studies confirmed the presence of bromine covalently bound with nanotubes as well as the formation of inclusion MWCNT–Br2 complexes. It was confirmed that Br2 molecules are absorbed on the surface of nanotubes (forming the CNT-Br2 complex), while they can dissociate close to dangling bonds at CNT defect sites with the formation of covalent C−Br bonds. Thus, any covalent attachment of bromine to the graphitic surface achieved around room temperature is likely related to the defects in the MWCNTs. The best results, i.e., the highest amount of attached Br2, were obtained for brominated nanotubes brominated for 10 days, with the content of covalently bound bromine being 0.68 at% (by XPS).

scholarly journals Self-assembly induced luminescence of Eu3+-complexes and application in bioimaging

2021 ◽  
Author(s):  
Ping-Ru Su ◽  
Tao Wang ◽  
Pan-Pan Zhou ◽  
Xiao-Xi Yang ◽  
Xiao-Xia Feng ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Rare Earth ◽  
Luminescence Intensity ◽  
Self Assembly ◽  
Room Temperature ◽  
Molecular Motion ◽  
Proof Of Concept ◽  
Room Temperature Phosphorescence ◽  
New Strategy ◽  
Size Controlled

Abstract Design and engineering of highly efficient emitting materials with assembly-induced luminescence, such as room temperature phosphorescence (RTP) and aggregation-induced emission (AIE), have stimulated extensive efforts. Here, we propose a new strategy to obtain size-controlled Eu3+-complex nanoparticles (Eu-NPs) with self-assembly induced luminescence (SAIL) characteristics without encapsulation or hybridization. Compared with previous RTP or AIE materials, the SAIL phenomena of increased luminescence intensity and lifetime in aqueous solution for the proposed Eu-NPs are due to the combined effect of self-assembly in confining the molecular motion and shielding the water quenching. As a proof of concept, we also show that this system can be further applied in bioimaging, temperature measurement and HClO sensing. The SAIL activity of the rare-earth (RE) system proposed here offers a further step forward on the roadmap for the development of RE light conversion systems and their integration in bioimaging and therapy applications.

scholarly journals Nonreciprocal charge transport up to room temperature in bulk Rashba semiconductor α-GeTe

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yan Li ◽  
Yang Li ◽  
Peng Li ◽  
Bin Fang ◽  
Xu Yang ◽  
...  
Keyword(s):  
Charge Transport ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Ferromagnetic Layer ◽  
Spin Splitting ◽  
New Paradigm ◽  
Rashba Spin ◽  
Rashba Spin Splitting ◽  
Fundamental Insight ◽  
Insight Into

AbstractNonmagnetic Rashba systems with broken inversion symmetry are expected to exhibit nonreciprocal charge transport, a new paradigm of unidirectional magnetoresistance in the absence of ferromagnetic layer. So far, most work on nonreciprocal transport has been solely limited to cryogenic temperatures, which is a major obstacle for exploiting the room-temperature two-terminal devices based on such a nonreciprocal response. Here, we report a nonreciprocal charge transport behavior up to room temperature in semiconductor α-GeTe with coexisting the surface and bulk Rashba states. The combination of the band structure measurements and theoretical calculations strongly suggest that the nonreciprocal response is ascribed to the giant bulk Rashba spin splitting rather than the surface Rashba states. Remarkably, we find that the magnitude of the nonreciprocal response shows an unexpected non-monotonical dependence on temperature. The extended theoretical model based on the second-order spin–orbit coupled magnetotransport enables us to establish the correlation between the nonlinear magnetoresistance and the spin textures in the Rashba system. Our findings offer significant fundamental insight into the physics underlying the nonreciprocity and may pave a route for future rectification devices.

Correction to “Ligand Initiated Self-Assembly of Pt and Ir Nanoparticles about Ru(II) Diimines in Room Temperature Fluid Solution”

2013 ◽  
Vol 117 (7) ◽  
pp. 3683-3683
Author(s):  
Parbatee Samaroo Jagassar ◽  
Anthony Perri ◽  
Guillermo Ibarrola ◽  
Harry D. Gafney
Keyword(s):  
Self Assembly ◽  
Room Temperature ◽  
Fluid Solution

Chiral Molecular Cavities of Calix[4]Crown on Au(111)

2008 ◽  
Vol 8 (11) ◽  
pp. 5702-5707 ◽  
Author(s):  
Ge-Bo Pan ◽  
Jun Luo ◽  
Qi-Yu Zheng ◽  
Li-Jun Wan
Keyword(s):  
Self Assembly ◽  
Chiral Recognition ◽  
Scanning Tunneling ◽  
Racemic Mixture ◽  
Tunneling Microscopy ◽  
Geometrical Structures ◽  
Simple Method ◽  
Ordered Structures ◽  
Ordered Arrays ◽  
Stm Images

Well-ordered arrays of chiral molecular cavities have been constructed by self-assembly of inherently chiral calix[4]crown on Au(111) in 0.1 M HClO4 solution and investigated by scanning tunneling microscopy (STM). The chiral features are clearly observed in high resolution STM images. It is found that the adsorption of the two enantiomers results in the same ordered structures with upright orientation on Au(111). Moreover, only phase separation has been observed for the racemic mixture of the two enantiomers in the experiment. This is mainly due to the weak molecule-substrate interaction as well as asymmetric geometrical structures of the two enantiomers. The present study provides a simple method for construction of ordered arrays of chiral molecular cavities, which are of potential in chemical sensors, chiral recognition, and nonlinear optics.

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