Solution Processed Cu(In,Ga)S2 Thin Film And Nanowire Photovoltaics,
2014
University of Arkansas Little Rock
Solution Processed Cu(In,Ga)S2 Thin Film And Nanowire Photovoltaics, Johnthan Armstrong
Theses and Dissertations
Solar energy conversion is a highly attractive process for clean and renewable power for the future. Cu(In,Ga)(Se,S)2/CdS/ZnO has proven itself to be a worthwhile photovoltaic combination achieving record efficiencies upwards of 20%. These record efficiencies have been obtained through vacuum-based approaches. However, the high cost of vacuum-based fabrication processes become a barrier to affordable solar cells as an energy source. As a result, solution-based approaches have become the focus of many studies which have achieved record efficiencies of 15%. These solution-based approaches have not matched up with the vacuum-based approaches. In this work, we investigate methods to improve the solution-based …
Performance Analysis Of A Hybrid Raman Optical Parametric Amplifier In The O- And E-Bands For Cwdm Pons,
2014
CUNY City College
Performance Analysis Of A Hybrid Raman Optical Parametric Amplifier In The O- And E-Bands For Cwdm Pons, Sasanthi Peiris, Nicolas Madamopoulos, Neophytos A. Antoniades, Dwight Richards, Roger Dorsinville
Publications and Research
We describe a hybrid Raman-optical parametric amplifier (HROPA) operating at the O- and E-bands and designed for coarse wavelength division multiplexed (CWDM) passive optical networks (PONs). We present the mathematical model and simulation results for the optimization of this HROPA design. Our analysis shows that separating the two amplification processes allows for optimization of each one separately, e.g., proper selection of pump optical powers and wavelengths to achieve maximum gain bandwidth and low gain ripple. Furthermore, we show that the proper design of optical filters incorporated in the HROPA architecture can suppress idlers generated during the OPA process, as well …
Gesn Light-Emitting Devices,
2014
University of Arkansas, Fayetteville
Gesn Light-Emitting Devices, Yiyin Zhou
Graduate Theses and Dissertations
Silicon based optoelectronic devices have been investigated for decades. However, due to the indirect band gap nature of Si and Ge, developing of efficient light-emitting source on Si is still a challenging topic. GeSn based optoelectronic devices have the great potential to overcome this deficiency for several reasons. By adding more fraction of Sn into Ge, GeSn band gap could be reduced. The narrowed band gap could be developed for near to mid infrared applications. The alloy can even become the direct band gap material with a large Sn composition (beyond 8%). This feature could enhance the light emission from …
Highly Transparent, Self-Cleaning, And Antireflective Nanoparticle Coatings,
2014
University of Arkansas, Fayetteville
Highly Transparent, Self-Cleaning, And Antireflective Nanoparticle Coatings, Corey Seth Thompson
Graduate Theses and Dissertations
Current solar panel technologies require a sheet of glass to serve as both mechanical support and to protect the cells from the environment. The reflection from the glass sheet can reflect up to 8% of the incident light, reducing the power output of the panel. Antireflective coatings can be used to allow more light to enter the panel to be converted into usable electricity. However, no solid thin film materials exhibit a low enough index of refraction to serve as antireflective coatings for common solar glass. The main goal of this research was to investigate the self-cleaning, antifogging, and antireflective …
Development Of A High Precision Quantum Dot Synthesis Method Utilizing A Microfluidic Reactor And In-Line Fluorescence Flow Cell,
2014
California Polytechnic State University, San Luis Obispo
Development Of A High Precision Quantum Dot Synthesis Method Utilizing A Microfluidic Reactor And In-Line Fluorescence Flow Cell, William Henry Lafferty
Master's Theses
Quantum dots show great potential for use as spectral converters in solar cells, lighting applications, and biological imaging. These applications require precise control of quantum dot size to maximize performance. The quality, size, and fluorescence of quantum dots depend on parameters that are difficult to control using traditional batch synthesis processes. An alternative, high precision process was developed for the synthesis of cadmium-selenide quantum dots using a microfluidic reactor and fluorescence flow cell. The process required creating separate cadmium and selenium precursors that were then mixed in a nitrogen environment at 17°C. Using an NE-300® syringe pump, the solution …
Investigation Of The Dynamics Of Photocarriers During Photoelectrochemical Water Splitting By Combination Of Photoelectrochemistry And Transient Absorption Spectroscopy,
2014
Department of Chemistry, Zhejiang University, Hangzhou 310027, China;
Investigation Of The Dynamics Of Photocarriers During Photoelectrochemical Water Splitting By Combination Of Photoelectrochemistry And Transient Absorption Spectroscopy, Wen-Hua Leng
Journal of Electrochemistry
Semiconductor photoelectrochemical hydrogen production is an important and promising technology for utilizing solar energy. The efficiency of hydrogen production depends on the efficiencies of separation and transport of photo-generated carriers. A deep understanding of the behavior of these processes has guiding significance for designing efficient solar hydrogen device. photoelectrochemical and transient absorption spectroscopy methods are powerful tool for studying the microscopic dynamics and mechanism of photocatalytic reaction. This review describes the part of the latest results of the author regarding the semiconductor photoelectrochemical hydrogen production obtained by these methods,and the problems and future research priorities in this field are proposed.
Effects Of Thermal Boundary Conditions During Finite Element Modeling Of Physical Vapor Transport,
2014
Minnesota State University, Mankato
Effects Of Thermal Boundary Conditions During Finite Element Modeling Of Physical Vapor Transport, Wade Luhman
Journal of Undergraduate Research at Minnesota State University, Mankato
Physical vapor transport (PVT) is a material processing method commonly used to produce different types of semiconductor materials. Computer modeling of PVT is important to understand the fundamentals of the processing method. Due to the large amount of computer processing power and storage needed to solve the computer models many of the previously solved simulations have been simplified to efficiently utilize computer usage. Previous PVT computer simulations of mercurous chloride (Hg2Cl2) have assumed constant temperature profiles on the source and crystal substrate for simplicity. These simulations were performed using the FIDAP computational fluid dynamics software package. In this research the …
Single Cuo Nanowires Electrical Properties And Application On Photoelectrochemical Water Splitting,
2014
Washington University in St. Louis
Single Cuo Nanowires Electrical Properties And Application On Photoelectrochemical Water Splitting, Junnan Wu
McKelvey School of Engineering Graduate Student Theses & Dissertations
Charge transport in single crystal, p type copper oxide (CuO) nanowires (NWs) was studied through temperature based (120 K – 400 K) current-voltage (I-V) measurements of 2-terminal single NW devices. Individual CuO NWs with an average diameter of 220 nm were attached to Au electrodes 2.5 µm apart, using a dielectrophoresis method. I-V curves showed a transition from linear behavior at low bias to strong power law dependence (I ~ Va) at high bias, which can be attributed to space charge limited current (SCLC) mechanism. At low electrical fields (< 0.89 × 103 V·cm-1), the number of …
Three Dimensional Transient Asymmetric Flowfields In Physical Vapor Transport,
2014
Minnesota State University, Mankato
Three Dimensional Transient Asymmetric Flowfields In Physical Vapor Transport, Joseph Dobmeier
Journal of Undergraduate Research at Minnesota State University, Mankato
Physical Vapor Transport is a manufacturing process used to produce single crystals of semiconductor materials such as mercurous chloride (Hg2Cl2). In the past this time-varying process has been studied with numerical simulation by considering three dimensional flow using an axi-symmetric two dimensional model or by restricting the simulation to asymmetric two dimensional flow and dropping the assumption of axi-symmetry from the model. It is generally agreed that neither of these methods accurately represent the true behavior of the process. The purpose of this research was to extend the asymmetric two dimensional model to three dimensions thereby obtaining a solution which …
Polymer-Based Thermoelectric Devices,
2014
Purdue University
Polymer-Based Thermoelectric Devices, Stuart W. Hilsmier, Edward P. Tomlinson, Bryan Boudouris
The Summer Undergraduate Research Fellowship (SURF) Symposium
Currently, over 50% of all energy generated in the US is lost as waste heat, and thermoelectric generators offer a promising means to recoup some of this energy, if their efficiency is improved. While organic thermoelectric materials lack the efficiency of their inorganic counterparts, they are composed of highly abundant resources and have low temperature processing conditions. Recently, a new class of redox-active polymers, radical polymers, has exhibited high electrical conductivity in an entirely amorphous medium. In addition, these radical polymers have a simple synthetic scheme and can be highly tunable to provide desired electrical properties. In this study, the …
Development Of A Nanomanufacturing Process To Produce Atomically Thin Black Phosphorus,
2014
Bradley University
Development Of A Nanomanufacturing Process To Produce Atomically Thin Black Phosphorus, Andrew Stephens, Zhe Luo, Xianfan Xu
The Summer Undergraduate Research Fellowship (SURF) Symposium
Atomically thin black phosphorus (phosphorene) has both unique and desirable properties that differ from bulk black phosphorus. Unlike graphene, phosphorene has a bandgap, which makes it potentially useful for applications in the next generation of transistors. Large-scale applications of phosphorene, like other 2D materials, are limited by current production methods. The most common method of making phosphorene is mechanical exfoliation, which can only produce small and irregular quantities. In this work we investigate a top-down method of producing phosphorene by using a scanning ultrafast laser to thin black phosphorus flakes. Because the bandgap of phosphorene increases as layers are removed, …
Micro-Mechanics Simulation Tool Optimization,
2014
Purdue University
Micro-Mechanics Simulation Tool Optimization, Ruixuan Ren, Marisol Koslowski
The Summer Undergraduate Research Fellowship (SURF) Symposium
Crystalline films grown epitaxially on substrates consisting of a different crystalline material are of considerable interest in optoelectronic devices and the semiconductor industry. One way to progress in this field is to develop simulation tools based on specially designed numerical method. A nanoHUB simulation tool was developed based on the phase field theory, which considers the propagation of dislocations inside the crystalline film. However, the current tool needs several improvements to be more realistic and user-friendly. First, the inputs of the simulation tool are adjusted so that the user can use this tool directly without any additional calculation. The output …
Implementing The ‘Frozen Potential’ Approach On Adept To Analyze Thin Film Solar Cells,
2014
Purdue University
Implementing The ‘Frozen Potential’ Approach On Adept To Analyze Thin Film Solar Cells, Abhirit Kanti, Raghu Vamsi Krishna Chavali, Mark S. Lundstrom Phd, Muhammad A. Alam Phd
The Summer Undergraduate Research Fellowship (SURF) Symposium
Thin film solar cells have higher absorption coefficients than traditional Silicon solar cells. This means that lesser material is required to produce the same power output for a given intensity of solar illumination. As a result, they are less expensive, easier to install and have a wider range of applications. Analyzing the performance of cells requires separating the current into the photocurrent and the injection current based on the ‘Superposition Principle’. For thin film solar cells, this cannot be done using the conventional method. This is because these components are interdependent, and so modeling one’s behavior requires understanding the other. …
Development Of A Silicon Nanowire Mask Using Scanning Probe Microscopy,
2014
California Polytechnic State University, San Luis Obispo
Development Of A Silicon Nanowire Mask Using Scanning Probe Microscopy, Ross Gregoriev
Master's Theses
Scanning probe microscopy techniques were used to investigate the desorption of hydrogen passivated silicon to form SiO2 etch masks The application of the etch masks were planned on being used to manufacture silicon nanowires. Low concentration hydrofluoric acid was used to passivate the surface. The surface was selectively depassivated by SPM techniques. Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) were used to create the masks. The STM system used was found to desorb hydrogen from the surface faster than the STM could image and was considered incapable in the configuration investigated. This led to the use of atomic …
Effects Of Nanoholes Grown By Molecular Beam Droplet Epitaxy On Electrical Properties Of Two Dimensional Electron Gas,
2014
University of Arkansas, Fayetteville
Effects Of Nanoholes Grown By Molecular Beam Droplet Epitaxy On Electrical Properties Of Two Dimensional Electron Gas, Yusuke Hirono
Graduate Theses and Dissertations
The effects of nanoholes, grown by molecular beam droplet epitaxy, on the electrical properties of quantum well (QW) heterostructures are reported. To investigate how the depth of nanoholes affect the electrical properties of the QW heterostructures, the growth conditions for nanoholes were optimized with respect to their depth and density. Using the results of the optimization of the nanohole growth, three InGaAs pseudomorphic quantum wells with nanoholes were investigated with varied depth and a constant density. A QW heterostructure without nanoholes was grown as a reference structure. For all the samples, temperature dependent Hall effect measurements, noise studies as a …
Interfacial Interactions Between Carbon Nanoparticles And Conjugated Polymers,
2014
California Polytechnic State University, San Luis Obispo
Interfacial Interactions Between Carbon Nanoparticles And Conjugated Polymers, Yanqi Luo
Master's Theses
Conjugated polymer based electronics, a type of flexible electronic devices, can be produced from solution by traditional printing and coating processes in a roll-to-roll format such as papers and graphic films. This shows great promise for the emerging energy generation and conversion. The device performance of polymer electronics is largely dependent of crystalline structures and morphology of photoactive layers. However, the solution crystallization kinetics of conjugated polymers in the presence of electron acceptor nanoparticles has not been fully understood yet. In this study, solution crystallization kinetics of poly (3-hexylthiophene) in the presence of carbon nanotubes and graphene oxide has been …
Synthesis And Characterization Of Cdse/Zns Core/Shell Quantum Dot Sensitized Pcpdtbt-P3ht:Pcbm Organic Photovoltaics,
2014
California Polytechnic State University, San Luis Obispo
Synthesis And Characterization Of Cdse/Zns Core/Shell Quantum Dot Sensitized Pcpdtbt-P3ht:Pcbm Organic Photovoltaics, Buddy J. Bump
Master's Theses
Durable, cheap, and lightweight polymer based solar cells are needed, if simply to meet the demand for decentralized electrical power production in traditionally “off-grid” areas. Using a blend of Poly(3-hexylthiophene-2,5-diyl) (P3HT), Phenyl-C61-butyric acid methyl ester (PCBM), and the low band-gap polymer 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), we have fabricated devices with a wide spectral response and 3% power conversion efficiency in AM 1.5 conditions; however, this thin film system exhibits only 0.43 optical density at 500 nm. To improve the performance of this polymer blend photovoltaic, we aim to increase absorption by adding CdSe(ZnS) core (shell) quantum dots. Four groups of …
Effects Of Conformational Transformations On Electronic Transport Properties Of Optical Molecular Switches: An Ab Initio Study,
2014
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210008, China;
Effects Of Conformational Transformations On Electronic Transport Properties Of Optical Molecular Switches: An Ab Initio Study, Yuan-Yuan He, Jian-Wei Zhao
Journal of Electrochemistry
A series of model molecules with 4 kinds of conformational transformations have been investigated as optical molecular switches by using density functional theory combined with nonequilibrium Green’s function method. The theoretical calculations show that molecules after conformational transformations have photoswitching characteristics. We find that the photochromic molecules with the same conformational transformation usually have a similar current on/off state when they are applied as photoshwitches. Among these transformations, the molecular switch with E(“trans”)/Z(“cis”)-isomerisation of the NN double bond has the highest current on-off ratio. The influences of the energy gap (HLG) between the highest occupied molecular orbital (HOMO) and the …
Developent Of A Phospholipid Encapsulation Process For Quantum Dots To Be Used In Biologic Applications,
2014
California Polytechnic State University, San Luis Obispo
Developent Of A Phospholipid Encapsulation Process For Quantum Dots To Be Used In Biologic Applications, Logan Grimes
Master's Theses
The American Cancer Society predicts that 1,665,540 people will be diagnosed with cancer, and 585,720 people will die from cancer in 2014. One of the most common types of cancer in the United States is skin cancer. Melanoma alone is predicted to account for 10,000 of the cancer related deaths in 2014. As a highly mobile and aggressive form of cancer, melanoma is difficult to fight once it has metastasized through the body. Early detection in such varieties of cancer is critical in improving survival rates in afflicted patients. Present methods of detection rely on visual examination of suspicious regions …
Design, Implementation, And Test Of A Micro Force Displacement System,
2014
California Polytechnic State University, San Luis Obispo
Design, Implementation, And Test Of A Micro Force Displacement System, Evan Derek Cate
Master's Theses
The design and implementation of a micro-force displacement system was completed to test the force-displacement characteristics of square silicon diaphragms with side lengths of 4mm, 5mm, and 7mm with a thickness of 10um. The system utilizes a World Precision Instruments Fort 10g force transducer attached to a World Precession Instruments TBM4M amplifier. A Keithley 2400 source meter provided data acquisition of the force component of the system. A micro prober tip was utilized as the testing probe attached to the force transducer with a tip radius of 5um. The displacement of samples was measured using a Newport M433 linear stage …
