Characterization Of Nanostructured Zinc Oxide For Energy Harvesting Applications - Research Paper Example

Characterization of nanostructured Name: University: Course: Lecturer: Date: Abstract The report is based on discovery, development and the effects of the technological advancement in the section of physics. The case study is the ultraviolet-visible spectroscopy, which deals with the electronic transition, the electron microscopy and the X-rays. There are many elements that are characterized and operate under the influence of the ultraviolet-visible spectroscopy such as ZNO, electromagnetism etc. The full information is detailed below. The electron microscopy is of two types; the transmission electron microscopy (TEM) and the scanning electron microscopy (SEM.). The two are almost similar but differential by their operational criteria and structural layout as it will be discussed in the report. The x-ray knowledge is very essential in the health wise of human. Is used in the body therapy and observing the internal body structure that have problems. Such mal-functioning includes the bone fluctuations, pneumonia etc. The x-ray diffraction has also analyzed in the report. Ultraviolet–visible spectroscopy (UV) Background information. Ultraviolet-visible spectroscopy is defined to as assimilation or reflectance in ultraviolet-visible spectral area, which means that light, is used in the visible and adjacent ranges. Therefore, it directly affects the professed chemical color in place. In the ultraviolet spectral region, the electromagnetic field molecules undergo electronic transition, which is corresponding to fluorescence spectroscopy that deals with transitions in excited to ground state, and the absorption ranges transits in ground to excited states (Perkampus, 1992). All compounds are the same but what differentiate them is their colors, example; chlorophyll is green while quinone’s yellow; with that information we get to learn that human eye is like spectrometer which scrutinizes the beams of light that is reflected via the liquid or solid surface. NB. Although the sunlight seems to be white it comprises of many colors with different wavelengths. The involved colors in the visible portion can be dispersed when the light rays are passed through a prism where different light (color) bends at a certain angle in respect to wavelength. Some terms such as wavelength (distance separated by two adjacent colors) and frequency (the number of times or cycles made within a given time) The ultraviolet-visible absorption works under a principle; molecules with π-electrons or non-bonding electrons take up the energy as UV or visible lights to excite electrons to upper non-bonding molecular orbitals.NB. When the wavelength of the light is longer, then the electrons are excited easily (small gap to join the HOMO and LUMO) An example is Beer-Lambert Law, which states that ‘the absorbance of a solution is directly proportional to the concentration of the absorbing species in the solution and the path length’. Consequently, for particular path length, the ultraviolet spectroscopy is used to verify the absorption of the solution of the absorber. NB: The ultraviolet-spectrometer is a device used in laboratory to measure and analyze the light reflectance, ultraviolet compounds and visible region of electromagnetic fields thus giving the refraction index and coefficient extinction of a film in a spectral collection. The diagram of ultraviolet-visible spectrometer. Analytical concept of the ultraviolet-visible spectroscopy. The ultraviolet-visible spectroscopy deals with electronic transitions. It Gives room for one to derive wavelength and optimum compound absorbance. From the information gotten by achieving the wavelength and the absorbance compounds, this values are combined to give Beer Lambert Law (A = εbc), Absorbance (A) =Molar extinction coefficient (ε)*Path length (b)*Concentration(c) NB. The concentration of a solution or sample can be resolute when one is given the molar extinction coefficient and molar absorptivity. Therefore UV-visible spectroscopy is used to establish an unknown identity of the compounds. Using the equation E (energy) =h (Planks constant) c (Speed of the light)/λ (wavelength.) the energy of a compound can be calculated (Wade 501) Use of the ultraviolet-visible spectroscopy. 1. Is used in semi-conductor industries to establish how thick the films on wafer are and the optical property of them. 2. Using the Beer–Lambert law, uv-visible spectroscopy determines the absorbing power of the species in the solution. INTRODUCTION Uv-visible spectroscopy is the most convenient method of analyzing organic compounds qualitatively and quantitively. This makes it to be practiced in clinical laboratory for chemical analysis and research industries (Kumar, 2013). UV spectrum is as a result of electromagnetic radiations interaction of molecules or ions therefore form the background organic, inorganic and bio-chemicals analysis. UV spectrum is a graph of wavelength (λ) against the absorption. I.e. The radiation taken up at a corresponding wavelength is recorded and plotted versus the wavelength to achieve the spectrum under the process of known as scanning (Anderson et al. 2004). (Kumar, 2013). The maxi (the maximum absorption band) and the band intensity are the two key parameters that feature the ultraviolet spectral substances. The electrons are always in constant energy that only changes during state transition. When undergoing transitions, the electrons loss or gain equal amount of energy to make the two states equalize (163, Bohr). The ultraviolet-visible spectroscopy procedure of electron transition avail the tool for examining the matter’s electronic structure. Physicist and mathematician Beer from German distinguished between the light absorption and the light concentration relationships. He achieved this by holding an experiment using color comparator (instrument that determine the concentration of light by absorbing the same light.) Beer observed the diffused light in the sample and solution then he accustomed the path length up to when the transmitted light appeared to have similar concentration. Similar to visible light discharge and pre-occupation of ultraviolet radiations has contributed abundantly on electronic interactions. (J.W Ritter 19) CHARACTERIZATION ON ULTRAVIOLET-VISIBLE SPECTROSCOPY. Electromagnet spectrum: Visible spectrum is just a very minor area in the total spectrum. Since these radiations are very micro to be seen and analyzed by our naked eyes, therefore the electromagnetic spectrum has complemented the purpose. Therefore the electromagnetic spectrum captures lights with very small wavelengths e.g. gamma and x-rays and those with long wavelengths such as, radio and micro waves. (The chart above shows the wide range of electromagnetic spectrum wavelengths) NB. The energy of a certain region of the spectrum is relational to its frequency. The equation below shows the relationship: V (frequency) = C (velocity of the light) λ (wavelength) E (energy change) = V (frequency) x h (plank’s constant) C = 3x1010 cm/sec and h = 6x10-27 erg sec Ultraviolet-visible Absorption Spectra. Correct light absorption in the visible region of the spectrum enables understanding of why different compounds have different colors while others don not have. An instrument known as optical spectrometer accounts for the wavelengths after or during the absorption and the absorption degree at a specific wavelength which absorption takes place, as well as the level of absorption at each wavelength ( Manish, Manoj and Pandey, 2014) The absorbance is equal to molar concentration of the molecules used therefore its correct absorption rate is referred to as molar absorptivity. Molar absorptivity = A(absorbance) / C(concentration in moles per litre) x L(length of light in cm) Electron Microscopy. Background Information; A microscope is an instrument that magnifies objects or specimens to appear bigger or larger than the actual for clear observations.Upto to the mid of 19th century the microscopist had not yet discovered any microscope that could resolve figures less than half micrometer. As the the technology of cathode ray tube advanced, they could use electrons now instead of light (Hertz, 1857-94). The cathode rays can be converged into a single spot by use of magnetic field generated by long solenoid (Weichert, 1899). Short solenoid concentrates electron beams similar to how glass converges light from the sun (Goodhew et al., 2001). The light microscope’s magnifying lens has a resolution power limit of 250 nanometers almost equivalent to wavelength of the light. Therefore it implies that samples with wavelengths below or less that of the light cannot be distinguished from one another. So that the samples below the light wavelength can be differentiated, a microscope that uses an illumination source and perceives very micro wavelength is in demand. The electrons of high voltage, x-rays and neutrons are used instead of light therefore the development of electron microscope. The electron microscope replaced the light microscope. The electron microscopes are of two types; Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM.)There are two common types of electron microscopes: scanning (SEM) and transmission (TEM). In case of SEM, a metal that reflects electrons is used to coat samples during the experiment. The metal coating also conducts electrons thus preventing the samples from being charged. The incoming beam of electrons at high voltage is converted into a lesser beam which is scanned over the object. After these electrons have bounced from the surface of the specimen, an image is formed. This implies that the observer only the surface picture with no information on the internal structure. Unlike SEM, TEM generate an image that comprises of both the internal and the surface structure because the electron beam and the sample interacts as the electrons passes through the sample therefore the internal composition is differentiated (Pennycook and Peter, 2010),) If the samples are very thick they will absorb a lot of electron beam so the sample is recommended to be thin. When the speed of the electrons is very high, the wavelength becomes shorter and the vice-versa is true. The fast the electrons travel, the shorter their wavelength.  The determining strength of the proportional irradiated wavelength that forms the image. The smaller the wavelength the higher the resolution power of the microscope. The magnifying power of the microscope improves with increase in electron beam voltage. The electron microscopy is categorized as follows: 1. Transmission Electron Microscopy (TEM.) –This work under electron beam with high voltage which are generated by cathode. Scanning Electron Microscopy (SEM) - Scanning Electron Microscopy (SEM) is a technique that creates images when subordinate electrons are emitted after the major electrons are excited. The electrons are scanned with detectors forming an image by plotting the perceived signals against beam location (Vernon-Parry, 2000; Joy, 1986).   2. Transmission Electron Microscopy (TEM) TEM is a technique that the electron beams are passed via a thin object forming an image as the electrons beams interact with the specimen. The TEM has high resolving power thus analyzing very tiny objects. Transmission electron microscopy (TEM) it includes electron beams with high voltage from the cathode. This electron beam is very thin and almost transparent ( Pennycook and Peter, 2010) The instrument used in Transmission Electron Microscopy is Transmission Electron microscope. Scanning Electron Microscopy (SEM) Scanning Electron Microscopy (SEM) is a technique that creates images when subordinate electrons are emitted after the major electrons are excited. The electrons are scanned with detectors forming an image by plotting the perceived signals against beam location ( Vernon-Parry, 2000; Joy,1986).   SEM uses voltage with low speed to reduce the penetration of beam into the object in order to produce secondary electrons from the primary electrons. According to Pennycook and Peter (2010), the components used o make the SEM are; a) The Electronic Console. The console has knobs that controls and adjusts the device function ability e.g. the filament current working, focus, magnifying lens etc. This technique can be applied using computers through FEI Quanta 200 therefore the knobs, CTR and capturing devices are not necessary on the console. The control devices are computerized therefore the user involves the use of keyboards and mouse through the computer system thus there is no need to use entire manual way. The programmes rely on the GUI software to control the instrument instead of the manual knobs. b) The Electronic Column. I where the electron beams are produced absorbed and scanned through the specimen by deflection of electromagnetic coils. The lower part of the column is the specimen chamber where the secondary electron detector is situated. The secondary electron chamber is situated overhead the specimen stage. The diagram of the electron column is shown below. Figure 2. Scanning electron microscope column [1]. c) Electron gun: Is located above the column where loose electrons are produced by the thermionic radiations from the tungsten filaments. This filament regulates the amount of electrons parting the gun. d) Condenser Lenses: They converges the electron beams to pass through the focal point and this beam is analyzed down 1000 times from the initial. Also these lenses determine the intensity of the electrons when it focuses on the specimen. e) Apertures: The aperture may be many or single in the electron column in respect to the microscope used. The aperture minimizes eliminate and eliminate inappropriate electrons in lens. The final lens determines the diameter of the electron beam on the specimen which in turn gives the resolution and depth of the area. NB. Reducing the spot size increases the magnification and the depth of the field. f) Scanning System: Images are created by raftering the electron beam transversely the specimen by means of deflection of coils in the interior of the objective lens. The electron beam assumes a spherical shape when it lands on the specimen. g) Specimen Chamber: This is located at the bottom of the column where both the specimen stage and knobs are located. In addition, the resultant electrons from the specimen are absorbed to the detector through a positively charged electron. X-RAYS. Background. X-rays are components of X-radiations that are electromagnetic in nature. X-ray’s wavelength is within the range of 0.01 and 10 nanometers, 30 petahertz and 30 exahertz frequency and energy between 100eV and 100eV. The wavelength of X-rays is relatively smaller compared to that of UV and gamma rays. X-rays are classified either hard X-ray (photon energy greater than 5-10) or soft X-rays (photons energy below 5-10). Hard X-rays are used to scan internal structures of an object because of their high penetrating power e.g. during medical therapy or airport security check-ups. However soft X-rays are assimilated in air easily (Davies, 2008). X-ray is dangerous to living tissues due to the photon they carry sufficient energy, which ionizes atoms and disturbs the molecular bonds thus leading to cancer. In contrast, basing on the ionization character of the X-ray, it is used in treating cancer by killing the malignant cells in the process of radiation therapy. X-rays are produced by X-ray tube when electrons produced by hot cathode moving at high velocity hits a metal surface, the anode. Units of measure and exposure The ionizing ability of X-rays is determined by exposure. The ionizing radiation exposure is measured in coulomb/kilogram(c/kg) which is its SI unit. This gives amount ionizing radiation needed to generate a single coulomb of charge in a kilogram of substance. Introduction Production of X-rays. X-rays are created when a beam of electrons generated by hot cathode collides with a metal surface(anode) such as copper. On collision, the electrons are ionized and x-rays are released to occupy the left space of the falling down (Nielsen and Des McMorrow, 2011). Uses of X-rays. Examining the broken and disjointed bones. X-rays is essential in internalizing internal organs and pointing out the problems e.g. Pneumonia. They are used in surgeon therapy e.g. coronary angioplasty (Nielsen and Des McMorrow, 2011). How X-rays work X-rays can pass through the living tissues on the skin of human body since they have high penetrating and frequency power. As they go via the body, the photon energy is absorbed therefore the respective body tissue like bone gives a distinctive area on the x-ray image while the soft part show a dark region (Singh, 2011). When the x-ray process is being carried out, the victim is supposed to on a flat platform like lying on a table or leaning against a wall to ensure that the body is located between the photographic plate and the machine. X-ray takes less than a second since the rays obstructs the photographic plate, which captures an image. That image is fed to the computer system to be analyzed on the screen (Singh, 2011). A diagram of an x-ray therapy (Corne and Kate, 2009).  Safety Too much x-rays are harmful to the human health therefore a physician should not carry an x-ray more than thrice on one victim. The emissions of x-ray can cause cancer of the skin hence it should be controlled effectively (Nielsen and Des McMorrow, 2011). X-ray Powder Diffraction It refers to the speedy analytical approach applicable in phase identification about the crystalline materials and provides info on the unit cell measurements. The investigated materials are exceptionally grounded, standardized, and the middling bulk composition is resolved (Warren, 1990). Basic Principle of X-ray Powder Diffraction The principle of X-ray diffraction has its basis on constructive interferences of the monochromatic X-rays as well as the crystalline samples. Cathode ray tubes produce X-rays, and then they are filtered to bring forth, a monochromatic emission and projected towards these samples. Interactions of incident emissions with the samples produce constructive interference (as well as diffracted rays) whenever situations obey the Bragg's Law(nλ=2d sin θ). Then the diffracted X-rays become monitored, dealt with and counted up. The scanning of the samples through 2θ angles, the likely diffraction direction of lattices is achieved because of the randomized orientations of powdered materials. The process of converting the diffraction crests to the d-spacing gives room for the mineral to be identified since all the minerals have a set of distinct d-spacings (Jenkins and Robert, 2011). The diffraction techniques fall on the production of X-rays within the X-ray tubes. These X-rays are projected towards the samples, and the diffracted radiations are collected. The main constituent of all diffractions is the angle sandwiched between the incident ray and diffracted ray. (Jenkins and Robert, 2011). The crest locations exist wherever the X-ray beams have had diffraction with the crystal lattices. The distinct sets of d-spacing gotten from this pattern might be used in 'fingerprinting' the mineral (Jenkins and Robert, 2011). Application Is mainly applicable in identifying indefinite crystalline components (for example, mineral, inorganic materials) in fields such as geology, ecological sciences, material sciences, engineering and biological sciences. This knowledge is applied in the identification of fine-grained crystals, for example, clay and assorted layer clay that aren’t optical. Diffraction is used to determine the unit cell measurements as well as the purity of samples (Yang 2008). Application of X Rays Radiography: it is applicable in treatment and industries, especially in diagnosing and non-destructive testing of various solids that might be defective. Fluoroscopy techniques has the same fundamental principles as the photographic plates substituted by the fluorescent screens (Attwood, 2007). X rays technology is applicable in computerized axial tomography for scanning to generate cross-sectional pictures of the human internal organs. Radiography is also, used in examining and analyzing of paintings, whereby the gotten information, for example, the age of the paintings and the original brushstroke methods aid in identification and verification of the artists (Yang, 2008). Nanostructures of ZnO Nanobelts A nanobelt is termed to as a nanowire that has a geometrical shape and side surfaces that are sufficiently defined. The ZnO nanoblets are often developed through the sublimation processes of the ZnO powder lacking introduction of catalysts. The nanobelts have a regular width alongside its whole length. The common nanobelts have a width ranging from 50-300 nm. The nanobelts have a thicknesses that ranges between 10 and 30 nm. The polar nanobelts, that are the building blocks of nanorings, grow alongside [1010], with side surface ±(1210) and topmost/lowest surface ±(0001), and is typically ~15 nm wide and ~10 nm thick. The nanobelts have polar charges on their topmost and lowest surfaces (JPCM, 2015; Yangyang et al. 2012). Hierarchical nanostructures Altering the structure of the original component might considerably modify the morphological status of the oxide nanostructures. For instance, the mixture of ZnO and SnO2 powder can be used in the weight ratios of 1:1 (as the source materials) in growing a complex ZnO nanostructures. (JPCM, 2015). Poluminescence spectrum derived from ZnO nanobelt that is 200 nm and 6 nm respectively, exhibiting the blue-shift with decrese in the size of nanobelts. Nanosprings The nanosprings have even shapes that have a radius of ∼500–800 nm and uniformly distributed pitches. All the nanosprings are constituted of uniformly malformed single-crystal ZnO nanobelts (JPCM, 2015). In conclusion, the application of ultraviolet-visible spectroscopy technology is in the establishment of how thick the films on water are, and their optical properties in semi-conductor industries. Using the Beer–Lambert law, uv-visible spectroscopy determines the absorbing power of the species in the solution. TEM generate an image that comprises of both the internal and the surface structure because the electron beam and the sample interacts as the electrons passes through the sample therefore the internal composition is differentiated. The electron microscopy is categorized as either Transmission Electron Microscopy or transmission Electron Microscopy. Scanning Electron Microscopy (SEM) is a technique that creates images when subordinate electrons are emitted after the major electrons are excited. Bibliography Yang, Li L. Synthesis and optical properties of ZnO nanostructures. Norrköping: Department of Science and Technology, Linköping University, 2008. Vernon-Parry, K. Scanning electron microscopy: an introduction. Centre for Electronic materials: UMIST, Volume 13, Issue 4 (2000), 40–44 Joy, David C. and Howitt, D. Scanning Electron Microscopy, 1986, 457-467 Pennycook, Stephen J., and Peter D. Nellist. Scanning transmission electron microscopy imaging and analysis. New York: Springer, 2011. Manish M., Manoj Sharma B., and Pandey, O. UV–Visible light induced photocatalytic studies of Cu doped ZnO nanoparticles prepared by co-precipitation method. Volume 110, Issue null (2014), 386-397 Perkampus, Heinz, H. UV-VIS Spectroscopy and Its Applications. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. Anderson, Rosaleen J., David J. Bendell, and Paul W. Groundwater. Organic spectroscopic analysis. Cambridge: Royal Society of Chemistry, 2004 Goodhew, Peter J., R Beanland, and F. J. Humphreys. Electron microscopy and analysis. London: Taylor & Francis, 2001. Davies, Ray. X-Ray. London: Duckworth, 2008. Nielsen, J, and Des McMorrow. Elements of modern X-ray physics. Chichester, West Sussex: John Wiley, 2011. Corne, Jonathan, and Kate Pointon. Chest X-Ray Made Easy. London: Elsevier Health Sciences UK, 2009. Warren, B. E. X-ray diffraction. New York: Dover Publications, 1990 Jenkins, Ron, and Robert L. Snyder. Introduction to X-ray powder diffractometry. New York, NY ˜u.a: Wiley, 2012. Attwood, David T. Soft x-rays and extreme ultraviolet radiation : principles and applications. New York: Cambridge University Press, 2007 Singh, A. K. Advanced x-ray techniques in research and industry. Amsterdam: IOS Press, 2005. Kumar, C. S. S. R. UV-VIS and photoluminescence spectroscopy for nanomaterials characterization. Berlin London: Springer, 2013 JPCM. Zinc oxide nanostructures: growth, properties and applications. Journal of physics: Condensed matter. 2015. Yangyang Zhang, Manoj, Ram, K., Elias, Stefanakos, K., and Yogi, Goswami, D. Synthesis, Characterization, and Applications of ZnO Nanowires. Volume 2012, Article ID 624520 (2012), 1-17 Read More

NB: The ultraviolet-spectrometer is a device used in laboratory to measure and analyze the light reflectance, ultraviolet compounds and visible region of electromagnetic fields thus giving the refraction index and coefficient extinction of a film in a spectral collection. The diagram of ultraviolet-visible spectrometer. Analytical concept of the ultraviolet-visible spectroscopy. The ultraviolet-visible spectroscopy deals with electronic transitions. It Gives room for one to derive wavelength and optimum compound absorbance.

From the information gotten by achieving the wavelength and the absorbance compounds, this values are combined to give Beer Lambert Law (A = εbc), Absorbance (A) =Molar extinction coefficient (ε)*Path length (b)*Concentration(c) NB. The concentration of a solution or sample can be resolute when one is given the molar extinction coefficient and molar absorptivity. Therefore UV-visible spectroscopy is used to establish an unknown identity of the compounds. Using the equation E (energy) =h (Planks constant) c (Speed of the light)/λ (wavelength.) the energy of a compound can be calculated (Wade 501) Use of the ultraviolet-visible spectroscopy. 1. Is used in semi-conductor industries to establish how thick the films on wafer are and the optical property of them. 2. Using the Beer–Lambert law, uv-visible spectroscopy determines the absorbing power of the species in the solution.

INTRODUCTION Uv-visible spectroscopy is the most convenient method of analyzing organic compounds qualitatively and quantitively. This makes it to be practiced in clinical laboratory for chemical analysis and research industries (Kumar, 2013). UV spectrum is as a result of electromagnetic radiations interaction of molecules or ions therefore form the background organic, inorganic and bio-chemicals analysis. UV spectrum is a graph of wavelength (λ) against the absorption. I.e. The radiation taken up at a corresponding wavelength is recorded and plotted versus the wavelength to achieve the spectrum under the process of known as scanning (Anderson et al. 2004). (Kumar, 2013).

The maxi (the maximum absorption band) and the band intensity are the two key parameters that feature the ultraviolet spectral substances. The electrons are always in constant energy that only changes during state transition. When undergoing transitions, the electrons loss or gain equal amount of energy to make the two states equalize (163, Bohr). The ultraviolet-visible spectroscopy procedure of electron transition avail the tool for examining the matter’s electronic structure. Physicist and mathematician Beer from German distinguished between the light absorption and the light concentration relationships.

He achieved this by holding an experiment using color comparator (instrument that determine the concentration of light by absorbing the same light.) Beer observed the diffused light in the sample and solution then he accustomed the path length up to when the transmitted light appeared to have similar concentration. Similar to visible light discharge and pre-occupation of ultraviolet radiations has contributed abundantly on electronic interactions. (J.W Ritter 19) CHARACTERIZATION ON ULTRAVIOLET-VISIBLE SPECTROSCOPY.

Electromagnet spectrum: Visible spectrum is just a very minor area in the total spectrum. Since these radiations are very micro to be seen and analyzed by our naked eyes, therefore the electromagnetic spectrum has complemented the purpose. Therefore the electromagnetic spectrum captures lights with very small wavelengths e.g. gamma and x-rays and those with long wavelengths such as, radio and micro waves. (The chart above shows the wide range of electromagnetic spectrum wavelengths) NB. The energy of a certain region of the spectrum is relational to its frequency.

The equation below shows the relationship: V (frequency) = C (velocity of the light) λ (wavelength) E (energy change) = V (frequency) x h (plank’s constant) C = 3x1010 cm/sec and h = 6x10-27 erg sec Ultraviolet-visible Absorption Spectra.

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