In today’s world, there is a huge demand for energy. With the continuous depletion of fossil fuels, there is an urgent need for alternate forms of energy, in particular technologies that are renewable, sustainable, and inexpensive. Solar cells have been considered a promising potential solution to this problem, but issues with conventional photovoltaic cells based on crystalline materials include high manufacturing cost, poor durability, and limited versatility. Currently, only 0.25% of the United States electricity needs are met by solar energy; to contrast, coal provides almost 42% of the country’s electricity, despite the massive health and environmental effects associated with coal power. Photovoltaic cells have the potential to be more cost efficient and more environmentally friendly than the current mainstream sources of electricity production, with approximately 1kW-h of sunlight hitting each square meter of the Earth per hour (comparatively, the average American home uses around 10,837kW-h per year1). Colloidal quantum dots (CQDs) are one attractive alternative material for closing this cost gap because they offer the promise of low cost fabrication based on solution processing and tunable optical and electrical functionalities2.
CQDs are nanometer-sized semiconductor particles that are synthesized in the solution phase3. Their bandgaps can be tuned through the quantum size effect by varying the size of the nanoparticles. Therefore, they can be designed to absorb light over a wide range of wavelengths, and films made of these particles possess unique absorption and reflection spectra. The overall goal of my project is to address some of the issues in the current photovoltaics industry, more specifically to use inexpe...
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...oes an American Home Use?" U.S. Energy Information Administration - EIA - Independent Statistics and Analysis. n.p., 10 Jan. 2014. Web. 13 May 2014.
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4. Meinardi, Francesco, et al. "Large-area luminescent solar concentrators based on/Stokes-shift-engineered/'nanocrystals in a mass-polymerized PMMA matrix," Nature Photonics, 8, 392-399 (2014).
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Indium Gallium Arsenide (InGaAs) is able to convert pulses of light into electrical signals. In 1997 Copper Indium Diselinide (CuInSe2) was used in the most advanced solar conversion systems solar cells. At high temperatures Indium combines with Oxygen to form Indium Oxide
Yastrebova, N. V. (2007). High Efficiency multi-junction solar cells. sunlab.eecs.uottawa.ca: University of Ottawa, Centre for Research in
Nanoparticles have got considerable attention globally in recent years due to their wide range of applications in many fields like pharmaceutical applications environmental pollution control, catalysis, biological tagging, drug delivery systems, photonics, optoelectronics and material chemistry (Ghosh et al., 2012). Nanoparticles are considered to be the building blocks of next generation of electronics, optoelectronics, and various chemical biochemical sensors, in therapeutics and diagnostics (Pavani et al., 2013).
Online, Chemistry, ed. "Solar Powering the World." Solar Energy (Photovoltaic Cells). 29 July 2008 .
Soukoulis, C. M. (April, 1996) Photonic Band Gap Materials: The “Semiconductors” of the Future? Retrieved from http://cmp.physics.iastate.edu/soukoulis/publications/171.pdf
22. Rao, C. emsp14N emsp14R, et al. "Graphene: The New Two‐Dimensional Nanomaterial." Angewandte Chemie International Edition 48.42 (2009): 7752-7777.
Haldar et al. Hybrid Colloidal Au-CdSe Pentapod Heterostructures Synthesis and Their Photocatalytic Properties. Appl. Mater. Interfaces 2012, 4, 6266-6272
Inorganic nanowires often exhibit unique property that is useful for future applications. As the sizes of materials are decreasing down to the nanoscale level, the physical structure and chemical properties of nanomaterials are also diverging away from its bulk form [N&N]. Nanowires display the quantum confinement effect which describes the energy level of electrons as discrete unit [N&N]. For example, the transfer of electrons from the valence band to the conducting band requires a specific amount of energy [N&N]. Additionally, the surface area to volume ratio increases as the particles gets smaller [N&N]. This property supports many of the future application of TiO2 nanowires that requires a large surface a...
Although Solar Energy is a flexible source of where energy could be directly or indirectly converted into forms of energy, it’s still not perfect. With its inefficiency, scientists are trying to find alternative solution to store solar cells for as long as possible. The main process of capturing solar energy happens at the nanoscale. With solar cells, it gets more efficient the tinier it gets. The converting rate of solar energy is equally price competitive as fossil fuel, with a dollar per watt of solar energy. With the help of nanotechnology, it could help raise solar energy conversion efficiency and help lower costs making it the ultimate method of raw energy conversion. To make sure the process of generating energy is kept at a low cost and energy output...
During my Summer Research Internship at Microphysics Laboratory at UIC, I got an opportunity to work with a research group on fabrication of thin film CdTe based photovoltaic cells. The objective of the project was to grow a CdTe layer of one micron thickness by ‘Close Space Sublimation’ (CSS) process on a CdS layer so that it could be later transferred to Molecular Beam Epitaxy (MBE) for the growth of high p-type CdTe. Conventionally, full 6 micron thick CdTe layer is grown by CSS process. To achieve a uniform 1 micron thick CdTe layer, we tried different recipes by changing partial pressure of oxygen, chamber pressure and temperature of source and substrate. Besides, effects such as thermal oxidation and diffusion were properly analysed for post-deposition CdCl2 annealing. I lived up to it by reading a lot of literature and journals. For characterization of the wafers, Nomarski microscope was used to observe the grain size, spectrophotometer was used to analyse band-gap and thickness and Sun simulator was used to find the performance and efficiency of the solar cell. By appropriate design of the recipes and by understanding the effects of physical parameters on deposition, we achieved a uniform 1 micron deposition of CdTe. In addition to working in t...
Nanoparticles are defined as the microscopic particles with at least one dimension less than 100 nm. Nanoparticles are of immense scientific interest because of their vast potential applications in biomedicines, computer, electronics, and defense industries. Nanoparticles are of great scientific and technological interests because they can effectively act as bridge between the bulk form and atomic or molecular structures of the materials. Bulk materials possess constant physical and chemical properties regardless their sizes while nano-scaled materials possess varying properties depending on their sizes [Marignier, J.L., Belloni, J., Delcourt, M.O., Chevalier, J.P. Microaggregates of nonnoble metals and bimetallic alloys prepared
Nanoparticles of silica sand have been researching and producing progressively due to the unique features of nano scale size. Silica sand
Grundmann, Marius. Physics of Semiconductors: An Introduction Including Devices and Nanophysics. New York: Springer, 2006. Print.
The sol–gel method allows the synthesis of TiO2 nanoparticles with different morphologies like sheets, tubes, particles, wires, rods, mesoporous and aerogels. The sol–gel method is also used due to the easy technique, low price, the purity of oxides obtained and the lower synthesis temperatures.