Download or read book Characterization of Photocurrent and Voltage Limitations of Copper indium Gallium selenide Thin film Polycrystalline Solar Cells written by Christopher P. Thompson and published by ProQuest. This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin film polycrystalline CdS/Cu(In, Ga)(Se, S) 2 solar cells have great potential as a candidate for high efficiency, high throughput, low cost production. Cu(In, Ga)Se 2 devices have laboratory efficiencies approaching 20% and module efficiencies around 11%. However, most progress in device optimization has been the result of empirical studies; little is known about the device defect structure, and even less is known about the control of defects within the Cu(In, Ga)(Se, S) 2 absorber. Despite years of study, the complex nature of the Cu(In, Ga)(Se, S) 2 system has made progress towards a fundamental understanding of device behavior, and limiting defects a slow affair. The goal of this work is to shed further light on the nature of the limitations on photocurrent and voltage. The main topics covered in this thesis are: (1) fitting quantum efficiency curves calculated from an analytical model to measured quantum efficiency curves, and (2) Open circuit voltage temperature measurements. For the first section, series of devices with varying absorber layers will be analyzed, using the minority carrier diffusion length as the only fitting parameter. All other variables within the model will be supplied from direct and indirect measurements. We show that by using quantum efficiency, capacitance-voltage, and current-voltage measurements, we can generate excellent fits using only diffusion length as a fitting parameter. It is found that for Cu(In, Ga)Se 2 devices with E G [approximate]1.2eV, L=1000-1500nm.; for wide bandgap devices, with E G [approximate]1.4eV, L=10-400nm; for devices with E G [approximate]1.2eV, deposited with a low substrate temperature, L=650nm. Wide bandgap devices long wavelength collection is limited by minority carrier diffusion. For the second section, V OC (T) measurements are taken on devices with a wide range of absorbers, including some previously un-measured devices; absorbers grown with a Na deficiency. Analysis will focus on the activation energy of the dominant recombination mechanism, as well as low temperature saturation of V OC . Both of these parameters shed light on the limiting properties of devices. Cu(In, Ga)Se 2 with bandgap ranging from 1.2eV-1.4eV are limited by Shockley Read Hall recombination, and have a ratio of saturation voltage to bandgap of 80%. Lowering the electrical quality of the absorber by depositing the Cu(In, Ga)Se 2 layer at lower substrate temperature decreases the ratio of saturation voltage to bandgap to 64%, as a result of increased bandtail defect states. CuInS 2 devices and Cu(In, Ga)Se 2 devices with low or no Na are limited by hetero-interface recombination, and have a saturation voltage to bandgap ratio of ~60%.
Download or read book Chemical and Electronic Characterization of Copper Indium Gallium Diselenide Thin Film Solar Cells and Correlation of These Characteristics to Solar Cell Operation written by Michael Justin Hetzer and published by . This book was released on 2009 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This dissertation embodies solid state physics research to understand the basic physical mechanisms underlying the movement of charge inside solar cells, in particular, the high efficiency copper indium gallium diselenide (CIGS) solar cell. The fundamental physics of the operation of these complex polycrystalline alloys remains incompletely understood. CIGS based solar cells have obtained conversion efficiencies of nearly 20%. Solar cells based on this material have been examined in this work using high resolution, atomic scale techniques to better understand the fundamental operation of these solar cells as well as correlating these basic properties to the operation of the finished full solar cell devices. Auger Electron Spectroscopy (AES) measurements of the chemical composition taken with nanometer resolution in an ultra high vacuum secondary electron microscope show evidence for compositional changes at the grain boundaries of the CIGS layer. These findings support theoretical calculations that predict higher solar cell performance as a result. Additionally, measurements have been taken with cathodoluminescence spectroscopy (CLS) studying the band structure locally within the CIGS layers. Significant variation is present in the resulting spectra, even within single grains indicating improved uniformity could be a path to better solar cell operation. Attempts to correlate the chemical composition and the energy band structure using AES and CLS measurements have yielded some interesting initial results but more work remains to be done to obtain a deeper understanding of the physics involved in these solar cells. Correlations have been observed between the energy band structure and the performance parameters of the solar cell, such as efficiency. These results indicate the possibility of alloying between the different layers of the solar cell and also that this intermixing is detrimental to the performance of the solar cell. This work has revealed important fundamental characteristics of these materials regarding changes in the atomic composition and energy band structure and how these changes influence the performance of the CIGS layer.
Download or read book Advanced Characterization of Thin Film Solar Cells written by Mowafak Al-Jassim and published by Institution of Engineering and Technology. This book was released on 2020-09-17 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polycrystalline thin-film solar cells have reached a levelized cost of energy that is competitive with all other sources of electricity. The technology has significantly improved in recent years, with laboratory cell efficiencies for cadmium telluride (CdTe), perovskites, and copper indium gallium diselenide (CIGS) each exceeding 22 percent. Both CdTe and CIGS solar panels are now produced at the gigawatt scale. However, there are ongoing challenges, including the continued need to improve performance and stability while reducing cost. Advancing polycrystalline solar cell technology demands an in-depth understanding of efficiency, scaling, and degradation mechanisms, which requires sophisticated characterization methods. These methods will enable researchers and manufacturers to improve future solar modules and systems.
Download or read book Photoenergy and Thin Film Materials written by Xiao-Yu Yang and published by John Wiley & Sons. This book was released on 2019-03-19 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides the latest research & developments and future trends in photoenergy and thin film materials—two important areas that have the potential to spearhead the future of the industry. Photoenergy materials are expected to be a next generation class of materials to provide secure, safe, sustainable and affordable energy. Photoenergy devices are known to convert the sunlight into electricity. These types of devices are simple in design with a major advantage as they are stand-alone systems able to provide megawatts of power. They have been applied as a power source for solar home systems, remote buildings, water pumping, megawatt scale power plants, satellites, communications, and space vehicles. With such a list of enormous applications, the demand for photoenergy devices is growing every year. On the other hand, thin films coating, which can be defined as the barriers of surface science, the fields of materials science and applied physics are progressing as a unified discipline of scientific industry. A thin film can be termed as a very fine, or thin layer of material coated on a particular surface, that can be in the range of a nanometer in thickness to several micrometers in size. Thin films are applied in numerous areas ranging from protection purposes to electronic semiconductor devices. The 16 chapters in this volume, all written by subject matter experts, demonstrate the claim that both photoenergy and thin film materials have the potential to be the future of industry.
Download or read book Polycrystalline Thin Film Research Copper Indium Gallium Diselenide written by and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Copper indium gallium diselenide (CIGS) solar cells are one of the primary focuses of research by the Thin Film Material Science and Processing Group. The group develops processes and materials related to thin-film polycrystalline photovoltaic (PV) devices as well as the equipment required for routine analysis of these devices and materials. We work closely with other groups in the Materials Science Center to achieve a deeper understanding of thin-film materials and devices.
Download or read book Preparation and Characterization of Copper Indium Gallium Diselenide Films Used in the Absorber Layers of Thin film Solar Cells written by 陳富珊 and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Characterization of Silver Copper Indium Gallium Diselenide Thin film Solar Cells written by 吳俊杰 and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Characterization of Copper Indium Gallium Diselenide Powders and Films Used in the Absorber Layer of Thin film Solar Cells written by 吳忠憲 and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Copper Indium Gallium Selenide CIGS Solar Cells Fabricated on Flexible Light weight Stainless Steel Substrates for Space Applications written by Gaurav Aniruddha Naik and published by . This book was released on 2001 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Characterization of Copper Indium Gallium Diselenide and Copper Zinc Tin Sulfide Powders Used as the Absorber of Thin film Solar Cells written by 林詣軒 and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical and Photovoltaic Properties of Copper Indium gallium Diselenide Materials and Solar Cells written by Puruswottam Aryal and published by . This book was released on 2014 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: The demand for clean and renewable energy sources in recent years has motivated research on the development of low cost, thin film photovoltaic devices. As a consequence, tools for the investigation and characterization of thin film photovoltaic component materials and devices, which can be implemented in real time as well as under in-line and off-line measurement conditions, are becoming increasingly important. Real time spectroscopic ellipsometry (RTSE) and ex-situ mapping spectroscopic ellipsometry (SE) are powerful characterization tools suitable for applications in the optimization of device performance and the evaluation of thin film photovoltaics technology scale-up from dot cell sizes in research laboratories to full module sizes in factories. These non-destructive optical probes implement multichannel spectroscopic detection for achieving high measurement speed, while simultaneously yielding high precision light-matter interaction parameters. The interaction parameters can be analyzed to obtain layer thicknesses as well as their optical properties from which material properties such as composition can be determined. The layer thicknesses and their optical properties in turn provide insights into the fraction of incident light absorbed in the active layer of the solar cell and also provide a basis for short-circuit current optimization through optical simulations. In this dissertation research, Cu(In, Ga)Se2 films with different Ga contents have been prepared by a one stage co-evaporation process. These films have been studied by spectroscopic ellipsometry (RTSE) in real time during their deposition, which has been performed at high temperature (570oC). After cooling the films to room temperature, in-situ SE measurements were undertaken in order to extract the dielectric functions of the thin film materials. An extended parameterization was established through the fitting of these dielectric functions to analytical functions, followed by the development of expressions in the free parameters that describe these analytical functions versus the Ga content. As a result of this parameterization, dielectric function spectra can be predicted for any desired composition. This capability was applied for the structural and compositional mapping of CIGS thin films and solar cells deposited over 10 cm × 10 cm substrate areas. Correlations of the deduced structural and compositional parameters with the corresponding device performance characteristics have yielded important insights with the potential to assist in the optimization of solar cell devices incorporating thin CIGS layers. In addition, a methodology of external quantum efficiency simulation (EQE) has been developed that relies on ex-situ spectroscopic ellipsometry analysis of complete thin film solar cells and so does not require free parameters. The simulations have been applied to CIGS and a-Si:H solar cells, based on the assumption that all photo-generated carriers within the active layers of these cells are collected without any recombination losses. Thus, it should be noted the predicted EQE is the maximum that the solar cell having the given structure can generate, and the difference between the predicted and measured EQE for the same device can provide insights into recombination losses in the device. Because the predicted EQE is based on specular interfaces, it can also be lower than the measured values due to light trapping caused by rough surfaces and interfaces. In another research area of interest for CIGS materials and solar cells, the role of the stage II/III substrate temperature (540oC - 640oC) in the deposition of the films by the three stage process has been studied, as has its effect on device performance, sodium diffusion, and grain size. Since standard soda-lime glass does not tolerate temperatures above 570oC due to glass softening, specially engineered high temperature soda-lime glass produced by Nippon Electric Glass Co., Japan was used as the substrate material in this study. It was found that the average device performance improves up to 620oC as a consequence of reduced shunting and improved diode quality factor which affect the fill factor of the device. At 640oC, however, these parameters have exhibited a wider distribution, and thus have yielded a lower average efficiency for the cells. SEM micrographs of these devices showed that the grain size first increased with increasing temperature up to 620oC, and then showed a bimodal distribution at 640oC. Finally, ex-situ mapping ellipsometry has been applied in the study of silver nanoparticle thin films prepared by the drop casting method. These films are important because of the plasmonic effects they exhibit. Such effects can be exploited by integrating the nanoparticle layers into solar cells in order to promote light trapping, and hence, increase the overall efficiency of the cells. A study of these films with mapping spectroscopic ellipsometry provides a means of determining thickness uniformity over large areas that is critical for scale-up of the deposition processes. The uniformity of other parameters of the films such as the plasmon resonance energy and its broadening are equally important to ensure maximum coupling of light into the solar cell absorber layer.
Download or read book Copper Indium Gallium Selenide Thin Film Solar Cells written by Yang Tang and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The solar energy as one of the new energy sources and a regenerated energy is abundant and pollution-free. Most photovoltaic devices (solar cells) sold in the market today are based on silicon wafers, the so-called first generation" technology. The market at present is on the verge of switching to a "second generation" of thin film solar cell technology which offers prospects for a large reduction in material costs by eliminating the costs of the silicon wafers. Cadmium telluride (CdTe).
Download or read book Growth and Characterization of Copper Indium Diselenide Polycrystalline Thin Films for Photovoltaic Applications written by Michael G. Engelmann and published by . This book was released on 1999 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metastability of Copper Indium Gallium Diselenide Polycrystalline Thin Film Solar Cell Devices written by Jinwoo Lee and published by . This book was released on 2008 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theory of Graded Bandgap Thin Film Solar Cells written by Faiz Ahmad and published by Springer Nature. This book was released on 2022-05-31 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin-film solar cells are cheap and easy to manufacture but require improvements as their efficiencies are low compared to that of the commercially dominant crystalline-silicon solar cells. An optoelectronic model is formulated and implemented along with the differential evolution algorithm to assess the efficacy of grading the bandgap of the CIGS, CZTSSe, and AlGaAs photon-absorbing layer for optimizing the power-conversion efficiency of thin-film CIGS, CZTSSe, and AlGaAs solar cells, respectively, in the two-terminal single-junction format. Each thin-film solar cell is modeled as a photonic device as well as an electronic device. Solar cells with two (or more) photon-absorbing layers can also be handled using the optolelectronic model, whose results will stimulate experimental techniques for bandgap grading to enable ubiquitous small-scale harnessing of solar energy.
Download or read book Efficiency Enhancement of Copper Indium Gallium Di selenide Thin Film Solar Cell Using Optimez Material Propeties written by Nima Khoshsirat and published by . This book was released on 2014 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fabrication of Thin film Copper Indium Gallium Selenide CIGS Solar Cells for Space based Assets written by Joel P. Freyenhagen (CAPT, USAF.) and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
