Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Electrical and Computer Engineering (14)
- Physical Sciences and Mathematics (6)
- Power and Energy (5)
- Physics (4)
- Materials Science and Engineering (3)
-
- Education (2)
- Engineering Education (2)
- Engineering Physics (2)
- Environmental Sciences (2)
- Oil, Gas, and Energy (2)
- Aerospace Engineering (1)
- Chemical Engineering (1)
- Engineering Science and Materials (1)
- Geography (1)
- Higher Education and Teaching (1)
- Mechanics of Materials (1)
- Nanoscience and Nanotechnology (1)
- Operational Research (1)
- Operations Research, Systems Engineering and Industrial Engineering (1)
- Remote Sensing (1)
- Semiconductor and Optical Materials (1)
- Social and Behavioral Sciences (1)
- Structures and Materials (1)
- Systems Engineering (1)
- Teacher Education and Professional Development (1)
- Vocational Education (1)
- Publication Year
- Publication
- Publication Type
Articles 1 - 17 of 17
Full-Text Articles in Engineering
Enhancing Thermal Stability Of Perovskite Solar Cells With A Polymer Through Grain Boundary Passivation, Tanzila Tasnim Ava
Enhancing Thermal Stability Of Perovskite Solar Cells With A Polymer Through Grain Boundary Passivation, Tanzila Tasnim Ava
Electrical & Computer Engineering Theses & Dissertations
Organic-inorganic halide perovskite solar cells have emerged as a promising photovoltaic technology due to their superb power conversion efficiency (PCE) and very low material costs. While perovskite solar cells are expected to eventually compete with existing silicon-based solar cells on the market, their long-term stability has become a major bottleneck. In particular, perovskite films are found to be very sensitive to external factors such as air, UV light, light soaking, thermal stress and others. Among these stressors, light, oxygen and moisture-induced degradation can be slowed by integrating barrier or interface layers within the device architecture. However, the most representative perovskite …
Highly Transmissive Scalable Colored Coatings For Architectural Photovoltaic Panels, Akbar Ali Syed
Highly Transmissive Scalable Colored Coatings For Architectural Photovoltaic Panels, Akbar Ali Syed
Electrical & Computer Engineering Theses & Dissertations
Highly transmissive coatings were developed by fabricating thin films using SiO2 and SiO2/TiO2 core/shell nanoparticles on glass substrates and on the photovoltaic cell glass covers. This coating is to maintain an attractive color appearance of the exterior surface for architecturally integrated photovoltaics and can be coated on fabricated photovoltaic panels. The color and optical properties of the nanoparticle coating was investigated for different nanoparticle diameters of 200-400 nm for SiO2 nanoparticles and core/shell nanoparticles having SiO2/TiO2 structure with 300 ± 11 nm diameter, and SiO2/TiO2/SiO2 structure with …
Degradation Mechanism Due To Water Ingress Effect On The Top Contact Of Cu(In,Ga)Se2 Solar Cells, Deewakar Poudel, Shankar Karki, Benjamin Belfore, Grace Rajan, Sushma Swaraj Atluri, Sina Soltanmohammad, Angus Rockett, Sylvain Marsillac
Degradation Mechanism Due To Water Ingress Effect On The Top Contact Of Cu(In,Ga)Se2 Solar Cells, Deewakar Poudel, Shankar Karki, Benjamin Belfore, Grace Rajan, Sushma Swaraj Atluri, Sina Soltanmohammad, Angus Rockett, Sylvain Marsillac
Electrical & Computer Engineering Faculty Publications
The impact of moisture ingress on the surface of copper indium gallium diselenide (CIGS) solar cells was studied. While industry-scale modules are encapsulated in specialized polymers and glass, over time, the glass can break and the encapsulant can degrade. During such conditions, water can potentially degrade the interior layers and decrease performance. The first layer the water will come in contact with is the transparent conductive oxide (TCO) layer. To simulate the impact of this moisture ingress, complete devices were immersed in deionized water. To identify the potential sources of degradation, a common window layer for CIGS devices—a bilayer of …
Optimization Of Top Contact For Cu(In,Ga)Se2 Solar Cells, Grace Cherukara Rajan
Optimization Of Top Contact For Cu(In,Ga)Se2 Solar Cells, Grace Cherukara Rajan
Electrical & Computer Engineering Theses & Dissertations
As world energy demands continue to increase, the need to generate electricity from a broader variety of sources, including renewables, is more critical than ever. With costs still 30% higher than those of natural gas, solar energy is a viable contender, but more progress is needed to level the playing field with other forms of energy generation. The overall energy security can be enhanced by diversifying the energy supply. Among them, Cu(In,Ga)Se2 (CIGS) has gained significant momentum as a possible high efficiency and low cost thin film solar cell material. The capacity to scale up any photovoltaic technology is …
Bandgap Profiling In Cigs Solar Cells Via Valence Electron Energy-Loss Spectroscopy, Julia I. Deitz, Shankar Karki, Sylvain X. Marsillac, Tyler J. Grassman
Bandgap Profiling In Cigs Solar Cells Via Valence Electron Energy-Loss Spectroscopy, Julia I. Deitz, Shankar Karki, Sylvain X. Marsillac, Tyler J. Grassman
Electrical & Computer Engineering Faculty Publications
A robust, reproducible method for the extraction of relative bandgap trends from scanning transmission electron microscopy (STEM) based electron energy-loss spectroscopy (EELS) is described. The effectiveness of the approach is demonstrated by profiling the bandgap through a CuIn1-xGaxSe2 solar cell that possesses intentional Ga/(In + Ga) composition variation. The EELS-determined bandgap profile is compared to the nominal profile calculated from compositional data collected via STEM-based energy dispersive X-ray spectroscopy. The EELS based profile is found to closely track the calculated bandgap trends, with only a small, fixed offset difference. This method, which is particularly advantageous …
Diffusion Modeling Of Impurities Through The Molybdenum Back Contact Of Cigs Solar Cells, Chinedum John Akwari
Diffusion Modeling Of Impurities Through The Molybdenum Back Contact Of Cigs Solar Cells, Chinedum John Akwari
Electrical & Computer Engineering Theses & Dissertations
CIGS is a major technology in photovoltaics and depends heavily, as any other PV technology, on the capacity to achieve the highest efficiency possible to compete on the market. Alkaline elements, notably sodium and potassium, play a key role in this matter as they enhance the open circuit voltage and the fill factor of the CIGS solar cells. However, this effect exists only for very specific concentration of sodium and potassium. These impurities typically diffuse through the soda-lime glass substrate.
Via modeling of the SIMS data, we try to understand and predict the diffusion mechanisms of these impurities from the …
Study Of Modified Deposition Process For Cu(In,Ga)Se2 Solar Cell Back Contact, Tasnuva Ashrafee
Study Of Modified Deposition Process For Cu(In,Ga)Se2 Solar Cell Back Contact, Tasnuva Ashrafee
Electrical & Computer Engineering Theses & Dissertations
As the worldwide demand for renewable energy is increasing, growth of the global share of alternative energy sources would improve overall energy security as well as bring environmental benefits. So far, solar cells - the devices that convert direct sunlight into electricity - are dominated by silicon devices. Another alternative is thin film solar cell, whose main inspiration is to reduce the electricity production cost. Cu(In, Ga)Se2 (CIGS) solar cells are considered to have a great prospective because of reduced material and energy consumption during manufacturing. Many CIGS solar cell manufacturers are already exhibiting GW-scale production capacity. With the …
Modification Of Deposition Process Parameters For Uniform Indium Layer Deposition, Isaac Butt
Modification Of Deposition Process Parameters For Uniform Indium Layer Deposition, Isaac Butt
Electrical & Computer Engineering Theses & Dissertations
The need for more efficient light to energy converting cells has long been a subject of research and development. With abundant availability of solar energy that the earth receives, the photovoltaic industry has sought materials that could serve the purpose of great energy conversion. The photovoltaic industry is mainly dominated by Silicon owing to its abundant availability, reliability and economic cost. However, due to limitations on efficiency improvements, some focus has shifted toward III-V based solar cells with a great potential for attaining higher efficiency and multi-junction applications. However, the cost of the III-V materials is extremely high due to …
Developing A Student Learning Strategy To Bridge Virtual Learning And Hands-On Activity, Gon Namkoong, Hargsoon Yoon, Yonghee Suh
Developing A Student Learning Strategy To Bridge Virtual Learning And Hands-On Activity, Gon Namkoong, Hargsoon Yoon, Yonghee Suh
Electrical & Computer Engineering Faculty Publications
This paper addresses the effectiveness of combined virtual and physical hands-on activities in students’ learning which was infused in the capstone senior design project. Senior design projects are open-ended and are similar to the research that scientists perform toward a more comprehensive understanding of nature or new scientific knowledge. As a reinforced learning methodology to greatly assist students’ reasoning and problem-solving skills, virtual learning was first integrated at the planning stage of their projects. This approach is in contrast with the typical senior design courses where only limited resources are available for planning experiments. Using virtual learning, students are able …
Improving The Efficiency Of Organic Solar Cells By Varying The Material Concentration In The Photoactive Layer, Kevin Anthony Latimer
Improving The Efficiency Of Organic Solar Cells By Varying The Material Concentration In The Photoactive Layer, Kevin Anthony Latimer
Electrical & Computer Engineering Theses & Dissertations
Polymer-fullerene bulk heterojunction solar cells have been a rapidly improving technology over the past decade. To further improve the relatively low energy conversion efficiencies of these solar cells, several modifications need to be made to the overall device structure. Emerging technologies include cells that are fabricated with interfacial layers to facilitate charge transport, and tandem structures are being introduced to harness the absorption spectrum of polymers with varying bandgap energies.
When new structures are implemented, each layer of the cell must be optimized in order for the entire device to function efficiently. The most volatile layer of these devices is …
Hybrid Inorganic/Organic Nanostructured Tandem Solar Cells: Simulation And Fabrication Methods, Patrick Michael Boland Jr.
Hybrid Inorganic/Organic Nanostructured Tandem Solar Cells: Simulation And Fabrication Methods, Patrick Michael Boland Jr.
Electrical & Computer Engineering Theses & Dissertations
Organic solar cell technologies continue to be an extremely active area of scientific research. With their promise of providing low-cost, easily-processable, multi-application photovoltaics, these devices could very possibly be the most viable and practical form of renewable energy among many being explored. However, significant technological obstacles remain that must be overcome if this technology is to successfully realize the goal of providing abundant energy while simultaneously reducing dependence on fossil fuel-based sources. Compared with inorganic solar photovoltaics, power conversion efficiencies in organics are still too low to compete economically.
Much research has been accomplished over the past three decades in …
Design Of Organic Tandem Solar Cells Using Pcpdtbt: Pc61 Bm And P3ht: Pc71bm, Gon Namkoong, Patrick Boland, Keejoo Lee, James Dean
Design Of Organic Tandem Solar Cells Using Pcpdtbt: Pc61 Bm And P3ht: Pc71bm, Gon Namkoong, Patrick Boland, Keejoo Lee, James Dean
Electrical & Computer Engineering Faculty Publications
We conducted optical and electrical simulations with the goal of determining the optimal design for conjugated polymer-fullerene tandem solar cells using poly[2,6-(4,4-bis-(2-ethylhexyl)- 4H-cyclopenta[2,1- b;3,4- b′] dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT): [6,6]-phenyl C61 butyric acid methyl ester (PC61 BM) as a bottom cell and poly(3-hexylthiophene) (P3HT): [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) as a top cell. The effects of photon density, absorption, balanced and unbalanced charge carrier transport, and bimolecular recombination in the two subcells were incorporated into the simulations. We found that the maximum energy conversion efficiency (η) is 9% when charge carrier mobilities in …
Energy From The Skies: Empowering Future Generations, Petros J. Katsioloudis, Stella Bondi, Walter F. Deal
Energy From The Skies: Empowering Future Generations, Petros J. Katsioloudis, Stella Bondi, Walter F. Deal
STEMPS Faculty Publications
The article discusses the development of photovoltaic technology. The first account of the use of solar power during war in western civilization was in the second century B.C. during the battle of Syracuse with Archimedes' famed Death Ray. In the late 1800s and early 1900s many advances occurred including the invention of solar-powered engines, the discovery of the photoconductivity of selenium and its ability to produce electricity when exposed to light, and the construction of the first solar cells from selenium wafers. Photovoltaic technology was born in the U.S. in 1954 when Daryl Chapin, Calvin Fuller, and Gerald Pearson developed …
Evolution Of The Band Structure Of Β-In2 S3−3x O3x Buffer Layer With Its Oxygen Content, N. Barreau, S. Marsillac, J. C. Bernède, L. Assmann
Evolution Of The Band Structure Of Β-In2 S3−3x O3x Buffer Layer With Its Oxygen Content, N. Barreau, S. Marsillac, J. C. Bernède, L. Assmann
Electrical & Computer Engineering Faculty Publications
The evolution of the band structure of β-In2 S3−3x O3x (BISO) thin films grown by physical vapor deposition, with composition x, is investigated using x-ray photoelectron spectroscopy. It is shown that the energy difference between the valence-band level and the Fermi level remains nearly constant as the optical band gap of the films increases. As a consequence, the difference between the conduction band level and the Fermi level increases as much as the optical band gap of the films. The calculation of the electronic affinity [ ] of the BISO thin films shows that it decreases linearly from 4.65 …
High-Efficiency Solar Cells Based On Cu(Inal)Se[Sub 2] Thin Films, S. Marsillac, P. D. Paulson, M. W. Haimbodi, R. W. Birkmire, W. N. Shafarman
High-Efficiency Solar Cells Based On Cu(Inal)Se[Sub 2] Thin Films, S. Marsillac, P. D. Paulson, M. W. Haimbodi, R. W. Birkmire, W. N. Shafarman
Electrical & Computer Engineering Faculty Publications
A Cu(InAl)Se2solar cell with 16.9% efficiency is demonstrated using a Cu(InAl)Se2thin film deposited by four-source elemental evaporation and a device structure of glass/Mo/Cu(InAl)Se2/CdS/ZnO/indium tin oxide/(Ni/Algrid)/MgF2. A key to high efficiency is improved adhesion between the Cu(InAl)Se2 and the Mo back contact layer, provided by a 5-nm-thick Ga interlayer, which enabled the Cu(InAl)Se2 to be deposited at a 530 °C substrate temperature. Film and device properties are compared to Cu(InGa)Se2 with the same band gap of 1.16 eV. The solar cells have similar behavior, with performance limited by recombination through …
Optical Properties Of Wide Band Gap Indium Sulphide Thin Films Obtained By Physical Vapor Deposition, N. Barreau, S. Marsillac, J. C. Bernède, T. Ben Nasrallah, S. Belgacem
Optical Properties Of Wide Band Gap Indium Sulphide Thin Films Obtained By Physical Vapor Deposition, N. Barreau, S. Marsillac, J. C. Bernède, T. Ben Nasrallah, S. Belgacem
Electrical & Computer Engineering Faculty Publications
Thin films of indium sulphide containing oxygen have been synthesized following a dry physical process. The constituents are deposited by thermal evaporation on glass substrates and then annealed under argon flow. Polycrystalline β-In2S3 containing oxygen thin films are obtained as soon as the temperature of annealing is between 623 and 723 K. In this paper, these β-In2S3 thin films have optically been studied. The optical band gap is direct. Its value is not dependent on the temperature of annealing. It is about 2.8 eV, which is higher than that of β-In2S3 …
A Total Systems Analysis Method For The Conceptual Design Of Spacecraft: An Application To Remote Sensing Imager Systems, Knut I. Oxnevad
A Total Systems Analysis Method For The Conceptual Design Of Spacecraft: An Application To Remote Sensing Imager Systems, Knut I. Oxnevad
Engineering Management & Systems Engineering Theses & Dissertations
Increased emphasis is being placed on improving the performance of space projects, within tighter budgets and shorter development times. This has led to a need for more efficient space system design methods. The research described here represents an effort to develop and evaluate such a method.
Systems engineering and concurrent engineering together provide the theoretical foundation for the method. The method, derived from both this theoretical foundation and ideas from experts in the space industry, emphasizes a total systems analysis approach, taking into account given mission requirements, and the mathematical modeling of interactions between system variables and between subsystems. The …