1,721,038 research outputs found
The early stages of CdTe epitaxial growth on gold single crystal electrode surfaces
No full textIn this dissertation an investigation into the initial phases of epitaxial CdTe monolayer film growth onto the low index planes of gold employing in-situ scanning tunnelling microscopy (STM) is presented. The CdTe films were grown by the sequential deposition of a partial monolayer of Te and Cd at underpotentials using Electrochemical Atomic Layer Epitaxy (ECALE). Atomic resolution images of the first UPD structures of tellurium prior to Cd deposition have been obtained in a CdSO4 solution indicating the stability of these adlayers towards emersion from solution. A new Te UPD structure could be imaged on the Au(111) surface under these conditions which could not be observed in previous ex-situ and in-situ studies. This exhibited a characteristic row morphology with long range ordering and could be identified as having a (3x9) unit cell registry with the underlying Au(111) substrate.The CdTe films were found to grow two-dimensionally in a layer-by-layer fashion. On the basis of detailed potential step experiments a refined mechanism for the observed structural transition from an initial (2x2) Te overlayer to a c(2x2) structure upon Cd UPD on the Au(100) surface is proposed, which has so far been a matter of some controversy in the literature. Atomically resolved STM images on the Au (111) and Au(110) plane revealed well-ordered CdTe structures with hexagonal symmetry. The adlayer unit cells were found to be consistent with a (3x3) and a (2x3) overlayer structure. The kinetics of CdTe electrocrystallization were studied by performing scan rate dependent cyclic voltammetry experiments. An analysis of this cyclic voltammetry data suggested that the Cd monolayer formation and dissolution Te modified gold surfaces proceeds by an instantaneous two-dimensional nucleation and growth mechanism.The results of an in-situ STM study in combination with ultra-high vacuum (UHV) electrochemical transfer experiments using x-ray photoelectron spectroscopy (XPS) and low-energy diffraction (LEED) on underpotentially deposited tellurium layers on Au(hkl) are also reported.</p
Direct electrodeposition of PbTe thin films on n-type silicon
No full textHigh quality lead telluride thin films were directly deposited onto n-type silicon (1 0 0) substrates by electrodeposition at room temperature. The deposition mechanism was studied using cyclic voltammetry. The films were characterized by scanning electron microscopy, energy dispersive X-ray, X-ray diffraction, and Fourier transform infrared spectroscopy. The results indicated that the deposited PbTe films exhibited a polycrystalline rock salt structure and good optical properties with a direct band gap of 0.31 eV
Template-free electrochemical deposition of tellurium nanowires with eutectic solvents
No full textElectrochemical deposition of tellurium from deep eutectic solvents (DES) at gold film electrodes produced films of tellurium nanowires. The deposition was evenly distributed over the gold surface, with an average diameter of ~70 nm and length of ~1 μm. Deposition was extremely sensitive to the applied potential, tellurium concentration and deposition bath temperature, with deviations away from optimised conditions preventing the formation of the desired nanostructure. Interestingly, replacing the chloride in a popular eutectic solvent with bromide or iodide had a significant impact on the resultant film structure, with bromide giving no clearly defined nanostructure but iodide giving nanoplatelets. This demonstrates a strong control of tellurium nanostructure by halide ions, offering a way to two distinct nanostructures from the same core experimental set up
Electroless deposition of tellurium nanowires in eutectic solvents using immobilised silver islands
No full textIn this work we demonstrate a new approach towards the electroless deposition of tellurium nanowires in deep eutectic solvents. Unlike most electroless deposition where the substrate is sacrificed to drive the reduction, our process uses immobilised silver epoxy islands on gold films to give localised galvanic displacement of the silver, resulting in an even growth of wires across the entire gold electrode surface. We demonstrate the strong dependence of the nanostructure on the experimental conditions, with changes in bath temperature, tellurium concentration and the halide component of the solvent leading to sizeable alterations in the nanowire geometry. This demonstrates electroless deposition as a promising synthetic route towards low-dimensional tellurium nanostructures
Template-free electrochemical deposition of tellurium nanowires with eutectic solvents
No full textElectrochemical deposition of tellurium from deep eutectic solvents (DES) at gold film electrodes produced films of tellurium nanowires. The deposition was evenly distributed over the gold surface, with an average diameter of ∼70 nm and length of ∼1 µm. Deposition was extremely sensitive to the applied potential, tellurium concentration and deposition bath temperature, with deviations away from optimised conditions preventing the formation of the desired nanostructure. Interestingly, replacing the chloride in a popular eutectic solvent with bromide or iodide had a significant impact on the resultant film structure, with bromide giving no clearly defined nanostructure but iodide giving nanoplatelets. This demonstrates a strong control of tellurium nanostructure by halide ions, offering a way to two distinct nanostructures from the same core experimental set up
Dataset supporting the publication "Solution-processed flexible thermoelectric nanocomposites based on P3HT/tellurium nanowires for smart applications" by S. Arumugam et al
No full textDataset supporting the publication "Solution-processed flexible thermoelectric nanocomposites based on P3HT/tellurium nanowires for smart applications" by S. Arumugam et al (2023) published in Synthetic Metals issn 0379-6779.
In this work, we fabricate a novel type of thermoelectric composite by mixing high-mobility poly(3,4-ethylene dioxythiophene), P3HT with tellurium nanowires (TeNW) and newly synthesized three different (S2-, SET and SPh) sulfur-contained tellurium nanowires. The advantage of the presence of sulfur in the hybrid film is to prevent aggregation and the ability to dissolve in polar solvents. The thermoelectric properties are investigated by varying the loading of tellurium nanowires into the polymer matrix. The spin coating method is used to fabricate the thermoelectric devices on Quartz substrates. We achieved a maximum power of 47.7μW/mk2, the highest reported for tellurium/P3HT nanowire composites. The results of this study also indicate that the doping of P3HT increases the thermoelectric properties of hybrid composites. The thickness of the hybrid thin films was investigated using SEM images.
Related projects:
EP/T027711/1 - Flexible Hybrid Thermoelectric Materials
The DOI for this data will become available once the paper has been published by Synthetic Metals issn 0379-6779
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Electrochemically copper-doped bismuth tellurium selenide thin films
Full text linkWe report the first results of a study on electrochemically doped copper bismuth tellurium selenide thin films electrodeposited from aqueous nitric acid electrolytes containing up to 2 mM of Cu(NO3)2. The effect of Cu(NO3)2 concentration on the composition, structure and thermoelectric properties of the bismuth tellurium selenide films is investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and Seebeck and Hall effect measurements. A Cu(NO3)2 concentration of 1.5 mM is found to offer a Seebeck coefficient of up to −390 μV K−1 at room temperature, which is the highest reported to date for an electrodeposited bismuth tellurium compound
Template-free nanostructured poly-3-hexylthiophene (P3HT) films via single pulse-nucleated electrodeposition
No full textA template-free method for the electrochemical deposition of poly(3-hexylthiophene) (P3HT) has been demonstrated. Electrodeposition is preceded by an electrochemical nucleation step, which is essential in producing an even film over the electrode surface without needing any pre-treatment of the electrode surface through surface coatings or self-assembled monolayers. The produced film is highly nanostructured, being made up of interconnected wire-like structures on the order of 100 nm, and readily delaminates as an intact film for straightforward analysis. The films are also highly conductive without needing post-treatment or chemical dopants. This technique offers a simple route to conductive organic films for thermoelectric generators, organic solar cells or field effect transistors
Dataset in support of the Southampton doctoral thesis 'Flexible Thermoelectric Energy Generators for E-textiles'
No full textThe dataset collected in the research thesis of "Flexible Thermoelectric Energy Generators for E-textiles". Contains SEM images, EDX elemental analysis and XRD crystal lattice characterisations. Additionally, the dataset contains hall probe and thermoelectric data and device power outputs and thermal images of devices at different thermal gradients. Data used in the dataset contributed to the publication:
“Screen-printed Bismuth telluride nanostructured composites for flexible thermoelectric
applications” A. Amin, R. Huang, D. W. Newbrook, V. Sethi, S. P. Beeby and I. S. Nandhakumar, J.
Phys. Energy, , DOI:10.1088/2515-7655/ac572e.
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Enhancing glucose oxidation: exploring 3D Pt nanowire frameworks for electrochemical studies
No full textHere, we report the use of highly reproducible free-standing 3D Pt nanowire frameworks (3D Pt NFs) to investigate the electrochemical oxidation of glucose. To create this unique Pt NFs, we utilize a lipidic bicontinuous cubic phase as a template. The resulting Pt NFs exhibits a unique 3D single diamond morphology with Fd3m symmetry. This intricate structure provides a large surface area and high electrocatalytic efficiency, making it more sensitive to glucose detection. Small Angle X-ray Scattering and Transmission electron microscopy investigations provided valuable insights into the nanoarchitecture of 3D Pt NFs. It highlights the interconnected nature of the nanowires and showcases the potential for optimized electrochemical performance. Very high current densities are registered for the glucose oxidation reactions at 3D Pt NFs during cyclic voltammetry investigations. This knowledge aids in the design and development of advanced electrocatalytic systems, fuel cells, biosensors, and other devices that leverage the unique characteristics of the 3D Pt framework. Graphical abstract: This study explores 3D Pt NFs for electrochemical glucose oxidation. Using a phytantriol template with two non-intersecting aqueous channels (A), Pt is electrodeposited in one channel (B), resulting in the formation of 3D Pt NFs after template washing (C). This approach demonstrates the potential for efficient glucose oxidation in the structured nanowire frameworks. (Figure presented.)</p
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