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Full-Text Articles in Nanoscience and Nanotechnology
Improving Quality Of Cvd Graphene Grown On The Copper Foil By Physical Polishing Electropolishing And Thermal Annealing Pretreatment Processes, Methawut Sirisom
Improving Quality Of Cvd Graphene Grown On The Copper Foil By Physical Polishing Electropolishing And Thermal Annealing Pretreatment Processes, Methawut Sirisom
Chulalongkorn University Theses and Dissertations (Chula ETD)
This study optimized the pretreatment processes (physical polishing (PP), electropolishing (EP), and thermal annealing) for high-quality graphene growth on thin copper (Cu) foils. PP using Brasso solvent was applied to smoothen the substrate surface, followed by EP with H3PO4 to reduce rolling lines and surface contamination. The EP process involved different H3PO4 concentrations (30-60%) and etching times (60-120 seconds). After thermal annealing at 860-940 ºC, graphene growth was performed using direct-liquid-injection chemical-vapor deposition with cyclohexane (C6H12) as the carbon precursor and nitrogen as the carrier gas. The optimized conditions involved PP and EP with 45% H3PO4 concentration and 90 seconds …
High-Pressure Study Of Hybrid Organic-Inorganic Perovskites And Double Perovskites, Ardimas -
High-Pressure Study Of Hybrid Organic-Inorganic Perovskites And Double Perovskites, Ardimas -
Chulalongkorn University Theses and Dissertations (Chula ETD)
Hybrid and double perovskite have been of great attraction for optoelectronic devices. However, exploring a feasible method to enhance their optical abilities remains a considerable challenge. Here, the researcher reports the pressure-induced phase transition as an effective way to modify optoelectronic properties. The researcher successfully synthesized the hybrid perovskite (MAPbI3) and the double perovskite (Cs2TiBr6) by the inverse temperature crystallization (ITC) and solution method, respectively. the researcher studied the pressure dependence phase transition and photoluminescence (PL) by placing the sample into diamond anvil cells (DACs) through Raman spectroscopy. The first principles method was used to support the idea. The researcher …
Nanoporous Cu-Based Catalytic Electrodes For Electrochemical Conversion Of Carbon Dioxide, Jidsucha Darayen
Nanoporous Cu-Based Catalytic Electrodes For Electrochemical Conversion Of Carbon Dioxide, Jidsucha Darayen
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research investigates the strategies to enhance copper electrodes for carbon dioxides reduction reactions (CO2RR) for generation of valuable chemical products, including methanol and acetaldehyde. Through modifications of physical characteristics of electroplated copper electrodes, particularly introduction of porosity, and chemical composition, namely formation of copper oxides, the key performance parameters for CO2RR including selectivity, Faradaic efficiency, and energy efficiency are examined. Furthermore, the relationships between copper electrodes’ plating variables (current density, deposition time, and bath solution), porosity and compositions, and corresponding CO2RR performances are constructed. The study has demonstrated that the ratio of CuSO4 and H2SO4 of bath solution, current …
A New Spinel High-Entropy Oxides Nanoparticles (Feconimnzn)3o4 As Anode Materials For Lithium-Ion Batteries, Maha Nur Aida
A New Spinel High-Entropy Oxides Nanoparticles (Feconimnzn)3o4 As Anode Materials For Lithium-Ion Batteries, Maha Nur Aida
Chulalongkorn University Theses and Dissertations (Chula ETD)
A novel (FeCoNiMnZn)3O4 HEO as an anode in lithium-ion batteries (LIBs) was developed for the first time. High-entropy oxide (HEO) of (FeCoNiMnZn)3O4 was synthesized using a hydrothermal technique to control size and crystallinity. We also synthesized oxides of each element (Fe, Co, Ni, Mn, Zn) from HEO composition under similar condition for comparison. The samples were then analyzed using XRD, SEM, TEM, EDS elemental mapping, surface area analysis, ICP-OES, and XPS. Cyclic voltammetry, galvanostatic charge-discharge, electrochemical impedance spectroscopy, and associated coulombic efficiencies were also used to study the electrochemical performance of (FeCoNiMnZn)3O4. Three samples with different preparation conditions, HEO-3, HEO-6, …
Biopolymer Nanocomposites For Food And Healthcare Applications, Tatiya Siripongpreda
Biopolymer Nanocomposites For Food And Healthcare Applications, Tatiya Siripongpreda
Chulalongkorn University Theses and Dissertations (Chula ETD)
This dissertation focuses on development of biopolymers by integrating nanomaterials to improve the properties of pristine polymers for enhancing the performances of chemical sensors and laser desorption/ionization mass spectroscopy (LDI-MS) applied for food quality control health monitoring and biomedical applications. The dissertation is divided into 4 parts: the first part, polylactic acid and cellulose were used for dual detection platform of biogenic amines for food spoilage indication. Highly porous PLA film is fabricated by adding nanosized calcium carbonate resulted in high sensing element entrapment. On another side of platform, pristine cellulose is modified with graphene oxide and exploited a substrate …
Tuning The Wettability Of Metal Surface With Electrodeposited Porous Copper And Graphene Coatings, Husam Eltigani
Tuning The Wettability Of Metal Surface With Electrodeposited Porous Copper And Graphene Coatings, Husam Eltigani
Chulalongkorn University Theses and Dissertations (Chula ETD)
Electrodeposition of porous copper is an interesting type of coating that is emerging for various applications. However, the understanding of the relationships between copper surface wettability control and electrodeposition parameters and post-electrodeposition storage conditions is quite limited. Furthermore, it is worthwhile to explore how nanomaterials such as graphene would interact with porous copper to provide surface wettability modifications. This work therefore aims to develop a framework for the relationship of copper and graphene deposition processes, storage conditions, and the wetting behavior of copper surfaces. The research work performed in this study is divided into 2 parts: (i) effects of plating …
Thermal Stability Characterization Of Tunneling Magneto Resistive Structure For Data Storage Applications, Pornchai Rakpongsiri
Thermal Stability Characterization Of Tunneling Magneto Resistive Structure For Data Storage Applications, Pornchai Rakpongsiri
Chulalongkorn University Theses and Dissertations (Chula ETD)
The conventional read sensor technology used in hard disk drives is the tunneling magneto resistive (TMR) device. The revolutions of technology have been developed to achieve high performance of reading signal resulting in very thin and complicated device layers which thermal induced degradation and defects would be concerned. In this research, a thermal stress has been applied to TMR devices between 150-250 ℃ for reliability investigation. The resistance, amplitude and asymmetry parameters, before and after the thermal stress, were measured using a quasi-static tester (QST). The results showed the temperature dependence of the percentage change in QST resistance, asymmetry and …
Preparation And Characterization Of Nickel Based Nanocomposite Coatings With Enhanced Mechanical And Surface Properties, Malay Kumar Das
Preparation And Characterization Of Nickel Based Nanocomposite Coatings With Enhanced Mechanical And Surface Properties, Malay Kumar Das
Chulalongkorn University Theses and Dissertations (Chula ETD)
Ni-W alloy and Ni-W/diamond monolayer and multilayer composite coatings were prepared by electrodeposition from a Ni-W plating bath with diamond particles suspended into the bath. Ni-W/diamond composite coatings were also prepared with varying amounts of Cobalt sulphate additives. The morphology and the composition of the deposits was investigated by means of SEM and EDS, respectively. The effect of operating conditions and additives on the Ni-W coatings were analyzed. The effect of the plating parameters, composite particle size, multilayer deposits and cobalt additives on microstructure and mechanical properties of the Ni-W/diamond composite coatings was investigated. The electrodeposited Ni-W/diamond deposits reported a …
Preparation Of Graphene Nanocomposites For Anticorrosion And Sensors, Nadtinan Promphet
Preparation Of Graphene Nanocomposites For Anticorrosion And Sensors, Nadtinan Promphet
Chulalongkorn University Theses and Dissertations (Chula ETD)
This dissertation focused on the development of graphene (GO) nanocomposite coating to improve various substrate properties for the sensor application, which is divided into 2 main parts. The first part is the development of GO incorporated into electroless nickel phosphorus (NiP) coating to improve the properties of metal for electrochemical sensor application. Nickel phosphorus - titanium dioxide sol - reduced graphene oxide (NiP-TiO2 sol -RGO) coated surface was successfully prepared by one-pot electroless deposition on the steel substrate. The results show that the homogeneously formation of water-repellent RGO film covering on the coated surface leading to improve the corrosion resistance …
Theoretical Studies On Electronic Properties Of Curved Graphene Quantum Dots And Lithium Adsorption On Graphene Quantum Dots, Naruwan Pattarapongdilok
Theoretical Studies On Electronic Properties Of Curved Graphene Quantum Dots And Lithium Adsorption On Graphene Quantum Dots, Naruwan Pattarapongdilok
Chulalongkorn University Theses and Dissertations (Chula ETD)
Graphene quantum dots (GQDs), with their attractive properties, are of interest to apply for electronic devices. Therefore, this dissertation aimed to investigate the electronic of curved graphene quantum dots (CGQDs) and the adsorption of lithium on GQDs. For the first part, two shapes of flat GQDs, rhomboidal (RGQDs) and hexagonal (HGQDs), were modified to make CGQDs with different folding axes and angles. Stabilities and electronic properties of CGQDs were studied using PBE/DNP. The results showed that the deformation energies of GQDs depend on sizes and folding axes but not their shapes. HOMO-LUMO gap variations, both widening and narrowing the gap, …