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Dye Sensitized Tandem Photovoltaic Cells

Description: This work provided a new way to look at photoelectrochemical cells and their performance. Although thought of as low efficiency, a the internal efficiency of a 9% global efficiency dye sensitized solar cell is approximately equal to an 18% efficient silicon cell when each is compared to their useful spectral range. Other work undertaken with this contract also reported the first growth oriented titania and perovskite columns on a transparent conducting oxide. Other work has shown than significant performance enhancement in the performance of dye sensitized solar cells can be obtained through the use of coupling inverse opal photonic crystals to the nanocrystalline dye sensitized solar cell. Lastly, a quick efficient method was developed to bond titanium foils to transparent conducting oxide substrates for anodization.
Date: December 21, 2009
Creator: Barber, Greg D.
Partner: UNT Libraries Government Documents Department

Analysis of the Mount Laguna Photovoltaic Cell Failure

Description: From summary: The purpose of this analysis is to provide photovoltaic (P/V) system design and field engineers with an understanding of the primary factors which can cause individual P/V cells in a module or an array to be forced into reverse bias and eventual failure and to provide guidelines for the adequate protection of the cells.
Date: January 1981
Creator: Anderson, E.
Partner: UNT Libraries Government Documents Department

Output Performance and Payback Analysis of a Residential Photovoltaic System in Colorado: Preprint

Description: Cost of installation and ownership of a 9.66-kilowatt (kW) residential photovoltaic system is described, and the performance of this system over the past 3 years is shown. The system is located in Colorado at 40 degrees latitude and consists of arrays on two structures. Two arrays are installed on a detached garage, and these are each composed of 18 Kyocera 130-W modules strung in series facing south at an angle of 40 degrees above horizontal. Each 18-panel array feeds into a Xantrex/Schneider Electric 2.8-kW inverter. The other two arrays are installed on the house and face south at an angle of 30 degrees. One of these arrays has twelve 205-W Kyocera panels in series, and the other is made up of twelve 210-Kyocera panels. Each of these arrays feeds into Xantrex/Schneider Electric 3.3-kW inverters. Although there are various shading issues from trees and utility poles and lines, the overall output resembles that which is expected from PVWatts, a solar estimate program. The array cost, which was offset by rebates from the utility company and federal tax credits, was $1.17 per watt. Considering measured system performance, the estimated payback time of the system is 9 years.
Date: June 1, 2012
Creator: Johnston, S.
Partner: UNT Libraries Government Documents Department

Photovoltaic self-assembly.

Description: This late-start LDRD was focused on the application of chemical principles of self-assembly on the ordering and placement of photovoltaic cells in a module. The drive for this chemical-based self-assembly stems from the escalating prices in the 'pick-and-place' technology currently used in the MEMS industries as the size of chips decreases. The chemical self-assembly principles are well-known on a molecular scale in other material science systems but to date had not been applied to the assembly of cells in a photovoltaic array or module. We explored several types of chemical-based self-assembly techniques, including gold-thiol interactions, liquid polymer binding, and hydrophobic-hydrophilic interactions designed to array both Si and GaAs PV chips onto a substrate. Additional research was focused on the modification of PV cells in an effort to gain control over the facial directionality of the cells in a solvent-based environment. Despite being a small footprint research project worked on for only a short time, the technical results and scientific accomplishments were significant and could prove to be enabling technology in the disruptive advancement of the microelectronic photovoltaics industry.
Date: October 1, 2010
Creator: Lavin, Judith; Kemp, Richard Alan & Stewart, Constantine A.
Partner: UNT Libraries Government Documents Department

Defining Requirements for Improved Photovoltaic System Reliability

Description: Reliable systems are an essential ingredient of any technology progressing toward commercial maturity and large-scale deployment. This paper defines reliability as meeting system fictional requirements, and then develops a framework to understand and quantify photovoltaic system reliability based on initial and ongoing costs and system value. The core elements necessary to achieve reliable PV systems are reviewed. These include appropriate system design, satisfactory component reliability, and proper installation and servicing. Reliability status, key issues, and present needs in system reliability are summarized for four application sectors.
Date: December 21, 1998
Creator: Maish, A.B.
Partner: UNT Libraries Government Documents Department

Photovoltaic module performance and durability following long-term field exposure

Description: Our investigations of both new and field-aged photovoltaic modules have indicated that, in general, today's commercially available modules area highly reliable product. However, by using new test procedures, subtle failure mechanisms have also been identified that must be addressed in order to achieve 30-year module lifetimes. This paper summarizes diagnostic test procedures, results, and implications of in-depth investigations of the performance and durability characteristics of commercial modules after long-term field exposure. A collaborative effort with U.S. module manufacturers aimed at achieving 30-year module lifetimes is also described.
Date: September 8, 1998
Creator: Ellibee, D.E.; Hansen, B.R.; King, D.L.; Kratochvil, J.A. & Quintana, M.A.
Partner: UNT Libraries Government Documents Department

Charge transport in hybrid nanorod-polymer composite photovoltaiccells

Description: Charge transport in composites of inorganic nanorods and aconjugated polymer is investigated using a photovoltaic device structure.We show that the current-voltage (I-V) curves in the dark can be modelledusing the Shockley equation modified to include series and shuntresistance at low current levels, and using an improved model thatincorporates both the Shockley equation and the presence of a spacecharge limited region at high currents. Under illumination, theefficiency of photocurrent generation is found to be dependent on appliedbias. Furthermore, the photocurrent-light intensity dependence was foundto be sublinear. An analysis of the shunt resistance as a function oflight intensity suggests that the photocurrent as well as the fill factoris diminished as a result of increased photoconductivity of the activelayer at high light intensity. By studying the intensity dependence ofthe open circuit voltage for nanocrystals with different diameters andthus ! band gaps, it was inferred that Fermi-level pinning occurs at theinterface between the aluminum electrode and the nanocrystal.
Date: June 21, 2002
Creator: Huynh, Wendy U.; Dittmer, Janke J.; Teclemariam, Nerayo; Milliron, Delia; Alivisatos, A. Paul & Barnham, Keith W.J.
Partner: UNT Libraries Government Documents Department

Annual Report: Photovoltaic Subcontract Program FY 1990

Description: This report summarizes the progress of the Photovoltaic (PV) Subcontract Program of the Solar Energy Research Institute (SERI) from October 1, 1989 through September 30, 1990. The PV Subcontract Program is responsible for managing the subcontracted portion of SERI's PV Advanced Research and Development Project. In fiscal year 1990, this included more than 54 subcontracts with a total annualized funding of approximately $11.9 million. Approximately two-thirds of the subcontracts were with universities at a total funding of nearly $3.3 million. The six technical sections of the report cover the main areas of the subcontract program: the Amorphous Silicon Research Project, Polycrystalline Thin Films, Crystalline Silicon Materials Research, High-Efficiency Concepts, the New Ideas Program, and the University Participation Program. Technical summaries of each of the subcontracted programs provide a discussion of approaches, major accomplishments in FY 1990, and future research directions. Another section introduces the PVMaT project and reports on its progress.
Date: March 1, 1991
Creator: Summers, K. A.
Partner: UNT Libraries Government Documents Department

On the Effect of Ramp Rate in Damage Accumulation of the CPV Die-Attach: Preprint

Description: It is commonly understood that thermal cycling at high temperature ramp rates may activate unrepresentative failure mechanisms. Increasing the temperature ramp rate of thermal cycling, however, could dramatically reduce the test time required to achieve an equivalent amount of thermal fatigue damage, thereby reducing overall test time. Therefore, the effect of temperature ramp rate on physical damage in the CPV die-attach is investigated. Finite Element Model (FEM) simulations of thermal fatigue and thermal cycling experiments are made to determine if the amount of damage calculated results in a corresponding amount of physical damage measured to the die-attach for a variety of fast temperature ramp rates. Preliminary experimental results are in good agreement with simulations and reinforce the potential of increasing temperature ramp rates. Characterization of the microstructure and resulting fatigue crack in the die-attach suggest a similar failure mechanism across all ramp rates tested.
Date: June 1, 2012
Creator: Bosco, N. S.; Silverman, T. J. & Kurtz, S. R.
Partner: UNT Libraries Government Documents Department

Suppression of auger recombination in ""giant"" core/shell nanocrystals

Description: Many potential applications of semiconductor nanocrystals are hindered by nonradiative Auger recombination wherein the electron-hole (exciton) recombination energy is transferred to a third charge carrier. This process severely limits the lifetime and bandwidth of optical gain, leads to large nonradiative losses in light emitting diodes and photovoltaic cells, and is believed to be responsible for intermittency ('blinking') of emission from single nanocrystals. The development of nanostructures in which Auger recombination is suppressed has been a longstanding goal in colloidal nanocrystal research. Here, we demonstrate that such suppression is possible using so-called 'giant' nanocrystals that consist of a small CdSe core and a thick CdS shell. These nanostructures exhibit a very long biexciton lifetime ({approx}10 ns) that is likely dominated by radiative decay instead of non-radiative Auger recombination. As a result of suppressed Auger recombination, even high-order multiexcitons exhibit high emission efficiencies, which allows us to demonstrate optical amplification with an extraordinarily large bandwidth (>500 me V) and record low excitation thresholds.
Date: January 1, 2009
Creator: Garcia Santamaria, Florencio; Vela, Javier; Schaller, Richard D; Hollingsworth, Jennifer A; Klimov, Victor I & Chen, Yongfen
Partner: UNT Libraries Government Documents Department

Quarterly Report: Microchannel-Assisted Nanomaterial Deposition Technology for Photovoltaic Material Production

Description: Quarterly report to ITP for Nanomanufacturing program. Report covers FY11 Q2. The primary objective of this project is to develop a nanomanufacturing process which will reduce the manufacturing energy, environmental discharge, and production cost associated with current nano-scale thin-film photovoltaic (PV) manufacturing approaches. The secondary objective is to use a derivative of this nanomanufacturing process to enable greener, more efficient manufacturing of higher efficiency quantum dot-based photovoltaic cells now under development. The work is to develop and demonstrate a scalable (pilot) microreactor-assisted nanomaterial processing platform for the production, purification, functionalization, and solution deposition of nanomaterials for photovoltaic applications. The high level task duration is shown. Phase I consists of a pilot platform for Gen II PV films along with parallel efforts aimed at Gen III PV quantum dot materials. Status of each task is described.
Date: April 26, 2011
Creator: Palo, Daniel R.
Partner: UNT Libraries Government Documents Department

Development of a photovoltaic power supply for wireless sensor networks.

Description: This report examines the design process of a photovoltaic (solar) based power supply for wireless sensor networks. Such a system stores the energy produced by an array of photovoltaic cells in a secondary (rechargeable) battery that in turn provides power to the individual node of the sensor network. The goal of such a power supply is to enable a wireless sensor network to have an autonomous operation on the order of years. Ideally, such a system is as small as possible physically while transferring the maximum amount of available solar energy to the load (the node). Within this report, there is first an overview of current solar and battery technologies, including characteristics of different technologies and their impact on overall system design. Second is a general discussion of modeling, predicting, and analyzing the extended operation of a small photovoltaic power supply and setting design parameters. This is followed by results and conclusions from the testing of a few basic systems. Lastly, some advanced concepts that may be considered in order to optimize future systems will be discussed.
Date: June 1, 2005
Creator: Harvey, Matthew R. & Kyker, Ronald D.
Partner: UNT Libraries Government Documents Department

Manufacturing injection-moleded Fresnel lens parquets for point-focus concentrating photovoltaic systems

Description: This project involved the manufacturing of curved-faceted, injection-molded, four-element Fresnel lens parquets for concentrating photovoltaic arrays. Previous efforts showed that high-efficiency (greater than 82%) Fresnel concentrators could be injection molded. This report encompasses the mold design, molding, and physical testing of a four-lens parquet for a solar photovoltaic concentrator system.
Date: October 1, 1995
Creator: Peters, E.M. & Masso, J.D.
Partner: UNT Libraries Government Documents Department

Model institutional infrastructures for recycling of photovoltaic modules

Description: How will photovoltaic modules (PVMS) be recycled at the end of their service lives? This question has technological and institutional components (Reaven, 1994a). The technological aspect concerns the physical means of recycling: what advantages and disadvantages of the several existing and emerging mechanical, thermal, and chemical recycling processes and facilities merit consideration? The institutional dimension refers to the arrangements for recycling: what are the operational and financial roles of the parties with an interest in PVM recycling? These parties include PVM manufacturers, trade organizations; distributors, and retailers; residential, commercial, and utility PVM users; waste collectors, transporters, reclaimers, and reclaimers; and governments.
Date: January 1, 1996
Creator: Reaven, S.J.; Moskowitz, P.D. & Fthenakis, V.
Partner: UNT Libraries Government Documents Department

The OSHA and EPA programs on preventing chemical accidents and potential applications in the photovoltaic industry

Description: OSHA issued in 1992, the Process Safety Management (PSM) of Highly Hazardous Substances. This rule requires owners/operators of facilities that handle hazardous chemicals in quantities greater than the listed thresholds to establish all the elements of a PSM. EPA has issued in June 1996, the rules for a Risk Management Program which also refers to specific substances and threshold quantities. These rules are applicable to all the facilities that use or store any of 139 regulated substances at quantities ranging from 100 lb to 10,000 lb. The RMP rule covers off-site hazards, while the OSHA Process Safety Management (PSM) rule covers worker safety issues within the plant boundary. Some of the listed substances may be found in photovoltaic manufacturing facilities. This brief report presents the basic elements of these two rules and discusses their potential applicability in the photovoltaic industry.
Date: August 1, 1996
Creator: Fthenakis, V.M.
Partner: UNT Libraries Government Documents Department

Photovoltaic module certification/laboratory accreditation criteria development

Description: This document provides an overview of the structure and function of typical product certification/laboratory accreditation programs. The overview is followed by a model program which could serve as the basis for a photovoltaic (PV) module certification/laboratory accreditation program. The model covers quality assurance procedures for the testing laboratory and manufacturer, third-party certification and labeling, and testing requirements (performance and reliability). A 30-member Criteria Development Committee was established to guide, review, and reach a majority consensus regarding criteria for a PV certification/laboratory accreditation program. Committee members represented PV manufacturers, end users, standards and codes organizations, and testing laboratories.
Date: April 1, 1995
Creator: Osterwald, C.R.; Hammond, R.L.; Wood, B.D.; Backus, C.E.; Sears, R.L.; Zerlaut, G.A. et al.
Partner: UNT Libraries Government Documents Department

Introduction to Special Issue on PV Systems Performance and Reliability

Description: The papers in this special issue have been selected from the systems and balance-of- systems sessions at the 1998 Photovoltaic Performance and Reliability Workshop. The workshop was held November 3-5, 1998 and hosted by the Florida Solar Energy Center, Cocoa Beach, Florida under sponsorship of the US National Center for Photovoltaics (National Renewable Energy Laboratory and Sandia National Laboratories). The topics and issues addressed by these papers were identified in an invited review paper on PV systems by the guest editors. Their work was published earlier this year in Volume 7, Number 1 of Progress in Photovoltaics ('Photovoltaic Systems: An End-of-Millennium Review'). Experts in the PV community were asked to make presentations on these topics at the workshop. The papers that follow are the results of that effort. The papers are organized by topic: (1) codes and standards; (2) reliability; (3) design issues; and (4) commercialization.
Date: January 12, 1999
Creator: DeBlasio, R.; Post, H.N. & Thomas, M.G.
Partner: UNT Libraries Government Documents Department

Photovoltaics: advancing toward the millennium

Description: This document describes the state of photovoltaics in the closing years of the 20th century. It was produced using data from both DOE -sponsored researchers and industry sources. It opens with a 10-page overview, followed by an in-depth analysis of the industry and technologies. Illustrative case studies are used throughout.
Date: May 1, 1996
Partner: UNT Libraries Government Documents Department

Photovoltaic Cz silicon module improvements. Annual technical progress report, November 9, 1995--November 8, 1996

Description: Work focused on reducing the cost per watt of Cz silicon photovoltaic modules under Phase I of Siemens Solar Industries` DOE/NREL PVMaT 4A subcontract is described. Module cost components are analyzed and solutions to high-cost items are discussed in terms of specific module designs. The approaches of using larger cells and modulus to reduce per-part processing cost, and of minimizing yield loss are particularly leveraging. Yield components for various parts of the fabrication process and various types of defects are shown, and measurements of the force required to break wafers throughout the cell fabrication sequence are given. The most significant type of yield loss is mechanical breakage. The implementation of statistical process control on key manufacturing processes at Siemens Solar Industries is described. Module configurations prototyped during Phase I of this project and scheduled to begin production in Phase II have a projected cost per watt reduction of 19%.
Date: February 1, 1998
Creator: King, R.R.; Mitchell, K.W. & Jester, T.L.
Partner: UNT Libraries Government Documents Department

Low-cost metal substrates for films with aligned grain structures

Description: Polycrystalline metal substrates that possess a significant amount of in-plane and out-of-plane crystallographic texture have recently been developed for high-temperature superconducting film applications. These substrates enable the virtual elimination of large angle grain boundaries in subsequent epitaxial films, having been successfully utilized in various oxide thin film architectures. This paper describes the characteristics of these substrates, and briefly discusses their potential applicability in polycrystalline thin-film photovoltaic applications.
Date: June 1, 1996
Creator: Norton, D.P.; Budai, J.D.; Goyal, A.; Lowndes, D.H.; Kroeger, D.M.; Christen, D.K. et al.
Partner: UNT Libraries Government Documents Department

Seventh workshop on the role of impurities and defects in silicon device processing

Description: This workshop is the latest in a series which has looked at technological issues related to the commercial development and success of silicon based photovoltaic (PV) modules. PV modules based on silicon are the most common at present, but face pressure from other technologies in terms of cell performance and cell cost. This workshop addresses a problem which is a factor in the production costs of silicon based PV modules.
Date: August 1, 1997
Partner: UNT Libraries Government Documents Department

High-efficiency one-sun photovoltaic module demonstration using solar-grade CZ silicon. Final report

Description: This work was performed jointly by Sandia National Laboratories (Albuquerque, NM) and Siemens Solar Industries (Camarillo, CA) under a Cooperative Research and Development Agreement (CRADA 1248). The work covers the period May 1994 to March 1996. The purpose of the work was to explore the performance potential of commercial, photovoltaic-grade Czochralski (Cz) silicon, and to demonstrate this potential through fabrication of high-efficiency cells and a module. Fabrication of the module was omitted in order to pursue further development of advanced device structures. The work included investigation of response of the material to various fabrication processes, development of advanced cell structures using the commercial material, and investigation of the stability of Cz silicon solar cells. Some important achievements of this work include the following: post-diffusion oxidations were found to be a possible source of material contamination; bulk lifetimes around 75 pts were achieved; efficiencies of 17.6% and 15.7% were achieved for large-area cells using advanced cell structures (back-surface fields and emitter wrap-through); and preliminary investigations into photodegradation in Cz silicon solar cells found that oxygen thermal donors might be involved. Efficiencies around 20% should be possible with commercial, photovoltaic-grade silicon using properly optimized processes and device structures.
Date: October 1, 1996
Creator: Gee, J. M.
Partner: UNT Libraries Government Documents Department