Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Spectroscopic Studies On Silicon And Chalcopyrite Materials For Solar Energy Applications, Amandee Hua
Spectroscopic Studies On Silicon And Chalcopyrite Materials For Solar Energy Applications, Amandee Hua
UNLV Theses, Dissertations, Professional Papers, and Capstones
In this dissertation, silicon-based materials for photovoltaics and chalcopyrite-based materials for photoelectrochemical water splitting are investigated using various spectroscopic and microscopic techniques. Although silicon dominates the photovoltaic market, further improvement can be made by using an alternative low temperature passivation approach. Currently, thermally grown SiO2 passivation is commonly used for silicon solar cells. However, this technique requires high processing temperatures (>800 °C), which increases the thermal budget, potentially decreases the bulk quality of Si, and can lead to difficulties in implementing in production lines. Here, a S-based passivation approach is studied that require lower processing temperatures of ~550 °C. …
Novel Pathways To High-Efficiency Chalcopyrite Photovoltaic Devices: A Spectroscopic Investigation Of Alternative Buffer Layers And Alkali-Treated Absorbers, Michelle Mezher
UNLV Theses, Dissertations, Professional Papers, and Capstones
Within the past few years, breakthroughs in Cu(In,Ga)Se2 (CIGSe) thin-film photovoltaic device efficiencies (on a laboratory scale) were achieved utilizing alkali-treated (KF) absorbers. Na incorporation in the CIGSe absorber, either diffused from the substrate or deliberately deposited, affects the surface electronic properties of the CIGSe absorber. The role of Na, however, is still not fully understood with some studies suggesting that Na also passivates defects at the grain boundaries. Replacing Na with K offered an efficiency boost resulting in KF treatments becoming the new “hot topic” in the chalcopyrite field, both in terms of understanding how the treatment changes …
Spectroscopic Investigation Of The Chemical And Electronic Properties Of Chalcogenide Materials For Thin-Film Optoelectronic Devices, Kimberly Horsley
Spectroscopic Investigation Of The Chemical And Electronic Properties Of Chalcogenide Materials For Thin-Film Optoelectronic Devices, Kimberly Horsley
UNLV Theses, Dissertations, Professional Papers, and Capstones
Chalcogen-based materials are at the forefront of technologies for sustainable energy production. This progress has come only from decades of research, and further investigation is needed to continue improvement of these materials.
For this dissertation, a number of chalcogenide systems were studied, which have applications in optoelectronic devices, such as LEDs and Photovoltaics. The systems studied include Cu(In,Ga)Se2 (CIGSe) and CuInSe2 (CISe) thin-film absorbers, CdTe-based photovoltaic structures, and CdTe-ZnO nanocomposite materials. For each project, a sample set was prepared through collaboration with outside institutions, and a suite of spectroscopy techniques was employed to answer specific questions about the system. These …
Speciation And Spectroscopy Of The Uranyl And Tetravalent Plutonium Nitrate Systems: Fundamental Studies And Applications To Used Fuel Reprocessing, Nicholas A. Smith
Speciation And Spectroscopy Of The Uranyl And Tetravalent Plutonium Nitrate Systems: Fundamental Studies And Applications To Used Fuel Reprocessing, Nicholas A. Smith
UNLV Theses, Dissertations, Professional Papers, and Capstones
This dissertation explores the use of UV-Visible spectroscopy and Time Resolved Laser Induced Fluorescence spectroscopy as near real time process monitors of uranium and plutonium concentrations in aqueous reprocessing trains. The molar absorptivities and linear ranges of these metals were investigated under total nitrate and acid concentrations similar to those found in current reprocessing systems. Concurrent to this, a new multiple wavelength monitor was derived that is capable of determining the total nitrate concentration spectroscopically. This method uses the uranium absorbance spectrum to calculate the nitrate concentration in solution. When used as part of an Advanced Safeguard suite, this technique …