Semiconductor Nano crystals or quantum dots are materials that are typically 2-20 nm in diameter, consisting of approximately twelve to fourteen thousand atoms. The effect of quantum confinement results, in the electrons and holes in the Nano crystal to exhibit quantized energy states; thus enabling them to exhibit novel physical properties that are not found in their bulk counterparts. Research in semiconductor quantum dots started with the realization that the optical and electronic properties of these particles were strongly dependent on particle size, due to quantum confinement of the charge carriers in small spaces.
What: In this project, plasmonic nanoparticles are used to create hot electrons from solar energy, as they provide the best chances of capturing the electrons’ energy. The hot electrons’ role is to break down water molecules into hydrogen and oxygen.
In the contexts of history and research, interest in heterogeneous photocatalysis can be traced back to many decades when Fujishima and Honda discovered in 1972 the photochemical splitting of water into hydrogen and oxygen in the presence of TiO2 From this time, extensive research, much of it published, has been carried out to produce hydrogen from water in oxidation reduction reactions using a variety of semiconductor catalyst materials. With respect to a semiconductor oxide such asWO3, photocatalytic reactions are initiated by the absorption of illumination with energy equal to or greater than the band gap of the semiconductor. This produces electron-hole (e−/h+) pairs as in Equation (1.14), Figure
In order to form metal hydrides, heat is released during the process which is exothermic reaction. The amount of heat released during the adsorption of hydrogen is the same as the amount of heat required to desorb the hydrogen. Therefore, as the stability of hydride formed getting higher, the heat needed to desorb hydrogen also higher. The energy needed to release the hydrogen from MgH2 is approximately 25% higher than the heating value of hydrogen. Although many efforts have been done on the Mg-based hydrides in recent years, it is still a challenge to find out an appropriate hydride of light metals (Zhou, 2004). The relatively high activation energy exists in the adsorption and desorption process leading the chemisorption process may become
Previous/current Graduate Research. Entering graduate school I expanded my interest with the electricomagnetic spectrum in the nanoscale by researching topics such as: computational simulations of nanoantenna (NA), desalination via dielectric breakdown, and hydrogen evolution reactions (HER). Metallic gold (Au) nanoantenna onto two-dimensional (2-D) transition metal dichalcogenides (TMDs) exhibit extraordinary optical properties that allow nanoscale energy modulation. A localized surface plasmon resonance (LSPR) emerges when incident electromagnetic energy excites the conduction electrons, causing them to oscillate coherently on the surface of the NA at a resonant wavelength. The LSPR energy is dissipated into the environment via re-radiation, electron-phonon (lattice vibration) and subsequent phonon-phonon coupling, causing a rise in local thermal energy, and hot electron transfer. Therefore projects such as dimers, nanorods and prisms have become of my interest for they have an electric near field that enhances the surface plasmon resonance to 2-dimensional materials for (TMDs). Conversations with my advisor are ideal when it comes to
This fear led so many scientists to figure out methods and ways to examine the cancer cells and cure it. In this report focuses on the most recent developments in the chemical synthesis of metal Nanorods, more specifically the gold Nanorods and silver nanorods, their properties and by extension some of their applications. It also studies into details a few nanotechniques and how they are applicable to various situations. One application is Cancer Cell Imaging and Photothermal
porphyrin-based compound, known commercially as verteporfin, also shows promise in the treatment of macular degeneration by selectively halting the growth of harmful blood vessels under the retina. The photochemical and optical properties of porphyrin compounds have also made them a target of research in the field of molecular electronics. One goal of this research has been to produce improved optoelectronic devices such as photovoltaic cells, OLEDs and OFETs by imitating the early steps of photosynthesis. 3 The high thermal and photostabilities of porphyrin compounds also contribute to their appeal in the field of material science. Supramolecular structures of porphyrin compounds have also been studied for their electrical properties, and have been used to build nanoarchitectures and molecular assemblies ranging in length from several nanometers to the millimeter scale.1 This particular project focuses on two metalloporphyrins: (Tetraphenylporphyrinato)zinc(II) (Zn(TPP)) and (Tetraphenylporphyrinato)copper(II) (Cu(TPP)). Energy transfer in systems consisting of zinc
The use of hydrogen as a fuel requires the adoption of the fuel cells technology for their role in the reaction activity between hydrogen and hydrogen for the production of energy. The fuel cells convert more of their energy potential from the fuel source as compared to the regular gasoline fuels. The insignificance of the impact caused by the bi-products of such reactions makes it the much better option than the fossil fuels that face the threat of exhaustion. However, the adoption of hydrogen as the primary
Layered two-dimensional (2D) transition metal dichalcogenides (TMDs) exhibit unique properties such as ease of energy band engineering by adjusting the number of layers or by Van der Waals heterostructures.1 Such salient features of TMDs make them promising for a wide range of electronic and optoelectronic applications.2-4 However, the transformation of basic science studies into viable device technologies necessitates large-area synthesis of device-quality TMDs. Significant research is ongoing to grow monolayer (ML) TMDs using chemical vapor deposition
Pd-Ni/Al2O3 systems were investigated in the reaction of hydrogen oxidation in terms of their possible application as catalysts used in passive autocatalytic recombiners (PARs) used in nuclear power plants. Testing experiments, were carried out in a flowing system at different temperatures and humidity of the reaction mixture. The bimetallic catalysts exhibited higher response to the increase of temperature and higher resistance to inhibiting water than the monometallic palladium catalyst. They showed excellent stability during a few tens of hours, similarly, like their monometallic counterpart. Our bimetallic catalysts of hydrogen oxidation can be used as cheaper alternatives to catalysts based on the precious metals in the hydrogen oxidation without loss of their activity over time.
Thin flakes of TMDs can be peeled off from bulk materials using adhesive tape, applied to the substrates and then identified by light interference using similar techniques used to develop graphene. Fig 6c shows a thin monolayer flake peeled off from the bulk material (Fig 6a) mechanically with the tape. Oxide nanosheets as well as other materials can be obtained using this method. Using the mechanical method of exfoliation helps to produce flakes of high purity that
The interest in plasmon modes dates back to the beginning of the 20th century, but recent advances in structuring, manipulating and observing on the nanometer scale have revitalized this field even though these technological advances were at first driven by the increasing demand for a semiconductor based integrated electronic components, optical applications are now receiving increasing attention. Guiding light in an integrated optical system and interfacing with electronic components remain important challenges for research and development today. Nanostructures metals are believed to be one of the key ingredients of such future optoelectronic devices.
Catalysis is one of the most important phenomena both in nature and chemistry. Photochemistry, which means chemical changes induced by absorption of light, constitutes the basis of human life. Plasmonic nanoparticles are characterized by their well-known surface catalytic properties and strong light-matter interactions. Plasmonic nanoparticles are potentially useful in a number of critical technologies, including solar-to-chemical and solar-to-electrical energy conversion, molecular characterization, imaging, lasing, and cancer tissue targeting. These nanoparticles are characterized by their strong interaction with resonant photons through an excitation of surface plasmon resonance (SPR). SPR can be described as the
Another of the technical setbacks which current nanotechnology is facing is the low efficiency of the energy storage of current devices, and its main causes are technical inconveniences and the relatively high cost of new technology. For example, Huang, X., Han, S., Huang, W., and Liu, X. (2013) indicate that the reason why current solar cells are not highly efficient is a mismatch in wavelengths of the peak of high energy emission of sunlight and the peak of high efficiency of these devices. Therefore, energy efficiency has become a new source of nanotechnology (Gauthier & Genet, 2014, p. 576). Supercapacitors and many of the electrodes are made of carbon-based materials (Liu et
Among the others metal NPs, the recent interest in the CuNPs is propelled by both, the advances of these NPs as a frugal alternatives for sumptuous metal NPs in the area of micro-electronics applications as well as the possibility of exploring them as ultimate antimicrobial agent.