A5070469006- Molecular Junctions and Nanostructures
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Quantum and electron transport phenomena
- Graphene research and applications
- Organic Electronics and Photovoltaics
- Silicon Nanostructures and Photoluminescence
- Advanced Thermoelectric Materials and Devices
- Nanowire Synthesis and Applications
- Surface Chemistry and Catalysis
- Semiconductor materials and devices
- Electrocatalysts for Energy Conversion
- Surface and Thin Film Phenomena
- Advanced Physical and Chemical Molecular Interactions
- Advanced Data Processing Techniques
- Catalysis and Oxidation Reactions
- Advanced Chemical Physics Studies
- Advanced Thermodynamics and Statistical Mechanics
- Quantum Dots Synthesis And Properties
- Carbon Nanotubes in Composites
- Various Chemistry Research Topics
- Machine Learning in Materials Science
- Spectroscopy and Quantum Chemical Studies
- Advanced Surface Polishing Techniques
- Advanced biosensing and bioanalysis techniques
University of Babylon
2015-2024
University of Kerbala
2023-2024
Lancaster University
2015-2018
Association for Women in Science
2018
Lancaster City Council
2017
A quantum circuit rule for combining interference effects in the conductive properties of oligo(phenyleneethynylene) (OPE)-type molecules possessing three aromatic rings was investigated both experimentally and theoretically. Molecules were type X-Y-X, where X represents pyridyl anchors with para (p), meta (m) or ortho (o) connectivities Y a phenyl ring p m connectivities. The conductances GXmX (GXpX) form X-m-X (X-p-X), (para) connections central ring, predominantly lower (higher),...
The conductance and the decay of as a function molecular length within homologous series oligoynes, Me3Si—(C≡C)n—SiMe3 (n = 2, 3, 4, or 5), is shown to depend strongly on solvent medium. Single molecule junction measurements have been made with I(s) method for each member 5) in mesitylene (MES), 1,2,4-trichlorobenzene (TCB), propylene carbonate (PC). In mesitylene, lower obtained across whole higher (β ≈ 1 nm–1). contrast, give values 0.1 0.5 nm–1 respectively). This behavior rationalized...
The most probable single-molecule conductance of each member a series 12 conjugated molecular wires, 6 which contain either ruthenium or platinum center centrally placed within the backbone, has been determined. measurement small, positive Seebeck coefficient established that transmission through these molecules takes place by tunneling tail HOMO resonance near middle HOMO-LUMO gap in case. Despite general similarities lengths and frontier-orbital compositions, experimental computationally...
The compounds and complexes 1,4-C6 H4 (C≡C-cyclo-3-C4 H3 S)2 (2), trans-[Pt(C≡C-cyclo-3-C4 (PEt3 )2 ] (3), trans-[Ru(C≡C-cyclo-3-C4 (dppe)2 (4; dppe=1,2-bis(diphenylphosphino)ethane) {P(OEt)3 }4 (5) featuring the 3-thienyl moiety as a surface contacting group for gold electrodes have been prepared, crystallographically characterised in case of 3-5 studied metal|molecule|metal junctions by using both scanning tunnelling microscope break-junction (STM-BJ) STM-I(s) methods (measuring current...
The single-molecule conductance of metal complexes the general forms trans-Ru(C≡CArC≡CY)2(dppe)2 and trans-Pt(C≡CArC≡CY)2(PPh3)2 (Ar = 1,4-C6H2-2,5-(OC6H13)2; Y 4-C5H4N, 4-C6H4SMe) have been determined using STM I(s) technique. display high (Y M Ru (0.4 ± 0.18 nS), Pt (0.8 0.5 nS); 4-C6H5SMe, (1.4 0.4 (1.8 0.6 nS)) for molecular structures ca. 3 nm in length, which has attributed to transport processes arising from tunneling through tails LUMO states.
A combination of density functional theory (DFT) methods and quantum transport (QTT) has been used to investigate the spectroscopic, electronic, thermoelectric properties carbon nanohoop molecules with different molecular templates. The connectivity type, along inherent strain, impacts behavior creates a destructive interference (DQI), which proves itself be powerful strategy enhance these molecules, making them promising candidates for applications.
Quantum interference (QI) is one of the most important phenomena that affects charge transport through single molecules. The effect a constructive and destructive quantum on electronic, thermoelectric spectroscopic properties oligo(phenyleneethynylene) based-molecular junctions has been investigated using combination density functional theory (DFT) methods, tight binding (Hückel) modelling (TBHM) (QTT). Molecules with carbonyl, diphenyl, ethane ethynylferrocene substituents show (DQI), which...
‘Short circuits’ to ancillary ligands in metal complex molecular wires are identified and ‘insulated wires’ presented.
Abstract The ancillary ligands 4′‐(4‐pyridyl)‐2,2′:6′,2′′‐terpyridine and 4′‐(2,3‐dihydrobenzo[ b ]thiophene)‐2,2′‐6′,2“‐terpyridine were used to synthesize two series of mono‐ dinuclear ruthenium complexes differing in their lengths anchoring groups. electrochemical single‐molecular conductance properties these studied experimentally by means cyclic voltammetry the scanning tunneling microscopy‐break junction technique (STM‐BJ) theoretically density functional theory (DFT). Cyclic data...
The single molecule conductances of a series bis-2,2':6',2″-terpyridine complexes featuring Ru(II), Fe(II), and Co(II) metal ions trimethylsilylethynyl (Me3SiC≡C-) or thiomethyl (MeS-) surface contact groups have been determined. In the absence electrochemical gating, these behave as tunneling barriers, with conductance properties determined more by strength electrode-molecule structure "linker" than nature metal-ion redox complex.
Controlling the orientation of molecular conductors on electrode surfaces is a critical factor in development single-molecule conductors. In current study, we used scanning tunnelling microscopy-based break junction (STM-BJ) technique to explore 'bare-bones' tripodal wires, employing different anchor groups (AGs) at 'top' and 'bottom' tripod. The triarylphosphine tris(4-(methylthio)phenyl)phosphine its corresponding phosphine sulfide showed only single high conductance feature resulting 1-...
The methyl blue-based molecular junctions are functional structures and promising candidates for thermoelectric applications.
Propagation of De Broglie waves through nanomolecular junctions is greatly affected by molecular topology changes, which in turn plays a key role determining the electronic and thermoelectric properties source|molecule|drain junctions. The probing realization constructive quantum interference (CQI) destructive (DQI) are well established this work. critical (QI) governing enhancing transmission coefficient T(E), thermopower (S), power factor (P) figure merit (Z
The use of tripod templates and the incorporation transition metals as metal centres would significantly enhance electronic thermoelectric properties molecular junctions, making them promising candidates for applications.
Abstract Heteroatom substitution into the cores of alternant, aromatic hydrocarbons containing only even‐membered rings is attracting increasing interest as a method tuning their electrical conductance. Here, effect heteroatom molecular non‐alternant hydrocarbons, odd‐membered rings, examined. Benzodichalcogenophene (BDC) compounds are rigid, planar π‐conjugated structures, with five‐membered fused to six‐membered aryl ring. To probe sensitivity or resilience constructive quantum...
Porous silicon layers (PS) have been prepared in this work via Photoelectrochemical etching process (PEC) of n type wafer 0.8 ohm.cm resistivity hydrofluoric (HF) acid 24.5 precent concentration at different times (5 to 25 min.). The irradiation has achieved using Tungsten lamp with wavelengths (450 nm, 535 nm and 700 nm). morphological properties these such as surface morphology, Porosity, layer thickness, also the rate investigated optical microscopy gravimetric method.
Background: Rotaxane molecule consists of three main parts: wheel, axle, and stoppers. This study was conducted to increase the number wheels get electronic, electrical thermal properties Nano molecular junctions based on rotaxane. Materials Methods: Calculations were performed evaluate transport geometrically optimization these using a combination DFT, SIESTA code, Gollum code non-equilibrium Green’s function formalism. Each attached opposing 35-atom (111) directed pyramidal gold...
Cycloparaphenylene molecules not only represent a promising host to examine quantum phenomena but also offer distinct electric and thermoelectric properties explore new designs features of materials.
Abstract Single-molecule porphyrin applications gain attention by using molecules as elementary blocks of electronic components involving metallic atoms. Theoretically, one type molecular-scale device is used in this article, consisting organometallic single with different metals (Zn, Mg, Cu and Fe), sandwiched between gold electrodes bound thiol anchor groups. The transmission Seebeck coefficients for Au|molecule|Au configurations were computed density functional theory (DFT). findings show...
Abstract Oligoynes are prototype molecular wires due to their conjugated system and the coherent tunneling transport, which aids this type of transfer charges over long distances. The electric thermoelectric characteristics for a series Oligoyne ((n) 3, 5, 7 9) studied explore fundamental transport mechanisms electrons crossing through single molecules, we probed both electrical conductance Seebeck coefficient Au|molecule|Au configurations using density functional theory (DFT). Our results...
Abstract We provide a brief overview of recent calculations and predictions electronic properties for single-molecules discuss some principles underpinning strategies enhancing their performance. Quantum interference effects in the (Pyridine-2Cyclopentene Metallic) organometallic-type molecules possessing four aromatic rings were investigate theoretically. In this paper, transmission study different types organometallic molecules. A calculation also provides powerful tool to estimate...
The exploring and understanding the electronic properties of molecules connected to metallic leads is a vital part nanoscience if molecule have future. This thesis documents study for various families organic organometallic molecules, which offer unique concepts new insights into molecular junctions. Different were studied using combination density functional theory DFT nonequilibrium Greens function formalism transport theory.The main results this are as follows. A quantum circuit rule...
Porous silicon (PSi) layers has been prepared in this work via photoelectrochemical (PEC) etching process of an n type wafers two resistivities (3.5 ohm.cm and 0.02 ohm.cm) hydrofluoric (HF) acid 24.5 precent concentration at different times (5 to 25 min). The irradiation achieved using laser beam 2W power 810 nm wavelength. We have studied the morphological structural properties PSi techniques Xray Diffraction (XRD) Scanning Electron Microscopy (SEM) Gravimetric method. data shows that...