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Fabrication of Sb-doped CIGS by selenization of stacked elemental layer and thin solar cellJian, Chong-Yao 27 August 2012 (has links)
This study is using selenization of stacked elemental layers to form Cu(In,Ga)Se2(CIGS). In the process, use Cu/Sb/In/Ga/Se precursor to heat to 550 oC at Se vapor in vacuum chamber. From the result of XRD¡BRaman and EPMA, that show of the precursor do not form to CIGS. After that, The result of using different layers precursor to form CIGS show that only Cu/In/GaSe/Se reach to form CIGS, but it still has second phase. According to the literature¡Athe reason for the formation of CIGS selenide process due to interdiffusion caused the formation of ternary solid phase, the solid phase diffusion reaction could be hampered.And then change to use rapid thermal selenization to form CIGS with two step of heating (hold at 300 oC and 650 oC) at N2 atmosphere. The laminated follow the best results in the selenide process Cu/In/GaSe/Se precursors in Se atmosphere, the (112) preferred orientation is 26.8o-26.9o in the XRD results of the fixed process conditions. EPMA composition analysis and comparison of Ga actual amount will increase with the estimated value of the amount of increase(Estimated value 4atom% actual value 2atom%¡FEstimated value 9.2tom% actual value 10atom%¡AGa/¢»=0.32), but the composition has yet to amend. Then will join Sb on CIGS observed from the SEM results Sb does improve the CIGS thin film flatness as well as to help grain growth in rapid thermal selenization, grain size of about 1 to 3£gm.
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Antimony Chalcogenide: Promising Material for PhotovoltaicsRijal, Suman 15 September 2022 (has links)
No description available.
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Studies on nucleoside H-phosphonoselenoate chemistry and chalcogen exchange reaction between P(V) and P(III) compoundsKullberg, Martin January 2005 (has links)
<p>In this thesis, the chemistry of compounds containing P-Se bonds has been studied. As a new addition to this class of compounds, H-phosphonoselenoate monoesters, have been introduced and two synthetic pathways for their preparation have been developed.</p><p>The reactivity of H-phosphonoselenoate monoesters towards a variety of condensing agents has been studied. From these, efficient conditions for the synthesis of H-phosphonoselenoate diesters have been developed. The produced diesters have subsequently been used in oxidative transformations, which gave access to the corresponding P(V) compounds, <i>e.g</i>. dinucleoside phosphoroselenoates or dinucleoside phosphoroselenothioates.</p><p>Furthermore, a new selenizing agent, triphenyl phosphoroselenoate, has been developed for selenization of P(III) compounds. This reagent has high solubility in organic solvents and was found to convert phosphite triesters and H-phosphonate diesters efficiently into the corresponding phosphoroselenoate derivatives.</p><p>The selenization of P(III) compounds with triphenyl phosphoroselenoate proceeds through a selenium transfer reaction. A computational study was performed to gain insight into a mechanism for this reaction. The results indicate that the transfer of selenium or sulfur from P(V) to P(III) compounds proceeds most likely <i>via</i> an X-philic attack of the P(III) nucleophile on the chalcogen of the P(V) species. For the transfer of oxygen, the reaction may also proceed <i>via</i> an edge attack on the P=O bond.</p>
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Studies on nucleoside H-phosphonoselenoate chemistry and chalcogen exchange reaction between P(V) and P(III) compoundsKullberg, Martin January 2005 (has links)
In this thesis, the chemistry of compounds containing P-Se bonds has been studied. As a new addition to this class of compounds, H-phosphonoselenoate monoesters, have been introduced and two synthetic pathways for their preparation have been developed. The reactivity of H-phosphonoselenoate monoesters towards a variety of condensing agents has been studied. From these, efficient conditions for the synthesis of H-phosphonoselenoate diesters have been developed. The produced diesters have subsequently been used in oxidative transformations, which gave access to the corresponding P(V) compounds, e.g. dinucleoside phosphoroselenoates or dinucleoside phosphoroselenothioates. Furthermore, a new selenizing agent, triphenyl phosphoroselenoate, has been developed for selenization of P(III) compounds. This reagent has high solubility in organic solvents and was found to convert phosphite triesters and H-phosphonate diesters efficiently into the corresponding phosphoroselenoate derivatives. The selenization of P(III) compounds with triphenyl phosphoroselenoate proceeds through a selenium transfer reaction. A computational study was performed to gain insight into a mechanism for this reaction. The results indicate that the transfer of selenium or sulfur from P(V) to P(III) compounds proceeds most likely via an X-philic attack of the P(III) nucleophile on the chalcogen of the P(V) species. For the transfer of oxygen, the reaction may also proceed via an edge attack on the P=O bond.
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Effect of heat treatments and reduced absorber layer thickness on cu(in,ga)se2 thin film solar cellsChandrasekaran, Vinodh 01 June 2005 (has links)
Thin film solar cells with Copper Indium Gallium Diselenide (Cu(In,Ga)Se2) absorber layers is one of the most promising candidates to emerge as an efficient solar cell technology in the near future. CIGS cells with efficiencies of 19.2 % have already been reported [1]. In this study, CIGS absorber layers are fabricated by a two-stage all-solid-state manufacture-friendly process. In the first stage, designated as precursor deposition, Copper and Gallium are sequentially deposited followed by co-deposition of Indium and Selenium. In the second stage, designated as selenization, the substrate is annealed at high temperatures in a selenium environment during which a thin layer of copper is also deposited. The typical thickness of the absorber layers fabricated by this process is around 2um. The ZnO transparent front contact of these cells is a bi-layer with a thin intrinsic layer and a thicker Al doped n-type layer.
These layers have been fabricated by different methods using Al-doped and undoped ZnO targets. The effect of the intrinsic layer thickness on the device performance was studied. Best performances were obtained when the intrinsic layer was around 350° thick and fabricated from an Al-doped ZnO target with excess oxygen partial pressure during deposition. The main focus of this work is to reduce the thickness of the CIGS absorber layers with no or minor loss in efficiency as this would translate directly into reduction in production costs and the amount of material being used. Reducing the thickness can be done either by reducing the deposition rates or duration of deposition. Due to the complex time-temperature profile during fabrication, reducing the thickness by reducing the deposition time would also affect the duration for which the substrates will be at high temperatures.
To understand what effect this would have in film formation and performance of the device, and if any post-deposition annealing would be required to compensate for the reduced time at temperatures, experiments were carried out with the cells being annealed at different stages before and after completion of the device itself. Annealing was done at 250°C in both air and vacuum. Although annealing the finished devices always yielded poorer performance, it was certainly helpful in understanding which aspects of the device were affected. Devices with reduced absorber layer thicknesses of 1.5um, 1.0um and 0.65um were fabricated. The devices showed improved Voc's when the absorber layer thickness was reduced to 1.5um and 1.0um but the Jsc's dropped by 2-3 mA/cm2. The 1.0um thick devices also showed an increase in band gap.
The thickness of the Molybdenum back contact layer was increased to see if the amount of Sodium from the substrate had any effect on the device performance. The Ga/In ratio was altered and its effect was also studied. The 0.65um thick devices showed a large reduction in Voc's and Jsc's. The effect of Selenization time and Selenium flux during Selenization were studied at each of the different thicknesses.
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Fabrication and Characterization of Novel 2SSS CIGS Thin Film Solar Cells for Large-Scale ManufacturingJayadevan, Keshavanand 01 January 2011 (has links)
A novel 2SSS (2 Step Solid Selenization) CIGS (Cu, In, Ga, Se) thin film solar cell recipe was developed which can be a replacement to the conventional co-deposition process usually employed for large-scale manufacturing. The co-deposition procedure is faced with multiple problems such as selenium incorporation, effective gallium incorporation in the absorber. It is a 2-step proprietary procedure with better control over growth mechanisms and material utilization for the absorber layer for the CIGS thin film solar cells. It makes use of solid selenium source as preferred by manufacturers. Each step of the 2-step procedure was dealt with separately for stoichiometric analysis and interesting trade-offs between materials such as gallium, indium and selenium was found. Solar cells with this proprietary absorber were fabricated on soda lime glass substrates. Results of the solar cells made with the 2SSS process matched with that of the co-deposition process with the quantum efficiencies near 80% of the co-deposition cells. These experiments are going to serve as the test bed for the pilot line that is intended to be installed at USF's research campus soon. The finished solar cells were characterized. The scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were some of the important tools during the analysis of stoichiometry and structural properties. The device performances were measured with the help of current-voltage (I-V) testing and quantum efficiency (QE) measurements.
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Modélisation, caractérisation et optimisation des procédés de traitements thermiques pour la formation d’absorbeurs CIGS / Modelling, characterization and optimization of annealing processes in CIGS absorber manufacturingOliva, Florian 04 April 2014 (has links)
L’énergie photovoltaïque jouera un rôle déterminant dans la transition énergétique future. Bien que les cellules solaires à base de silicium dominent encore le marché, leur coût de fabrication et le poids des modules limitent leur développement. Depuis quelques années, les industriels s’intéressent de plus en plus aux dispositifs à base de couches minces en raison de leurs procédés de fabrication rapides et peu onéreux sur de larges substrats. Cette technologie utilise une large variété de matériaux; les chalcopyrites tels que Cu(In,Ga)Se2 sont les plus prometteurs. Le procédé de fabrication de couches chalcopyrites le plus répandu est la coévaporation mais l’utilisation de vides très poussés rende cette technique peu adaptée à la production à grande échelle de modules bon marché. La solution alternative décrite dans ce travail est un procédé en deux étapes basé sur le recuit sous atmosphère réactive de précurseurs métalliques électrodéposés. Le développement de cette technologie passe par une meilleure compréhension des mécanismes d’incorporation et d’homogénéisation du gallium dans les couches formées et par une optimisation des étapes de recuit. Le premier objectif de ce travail de thèse est une étude des mécanismes réactionnels mis en jeu lors du procédé de recuit à travers l’étude de différents types de précurseur. Par la suite ces connaissances sont utilisées pour modéliser et optimiser un recuit industriel innovant. Ce travail est réalisé à l’aide de plans d’expérience (DOE) où l’influence de certains paramètres, les plus critiques est mise en évidence. Des voies d’optimisation sont proposées et des hypothèses faites afin d’expliquer les phénomènes observés. / Solar energy is promised to be a major actor in the future of energy production. Even if silicon based solar cells remain the main product their fabrication is energy consuming and requires heavy cover glass for protection, which reduce their development. For several years, commercial interest has shifted towards thin-film cells for which manufacturing time, large scale production, fabrication costs and weight savings are the main advantages. For thin film technology, a wide variety of materials can be used but chalcopyrite such as Cu(In,Ga)Se2 is one of the most promising. The most current method used for chalcopyrite formation is co- evaporation but this process is very expensive and not well suitable for large scale production due to high vacuum requirements. One alternative solution described in this work consists of a two-step technology based on the sequential electro-deposition of a metallic precursor followed by a rapid reactive annealing. However to reach its full potential this technology needs a better understanding of the Ga incorporation mechanism and of the selenization/sulfurization step. This work focuses first on formation mechanisms through the study of several kinds of precursor. This knowledge is then used to explain and to optimize innovative annealing processes. This study is achieved by observing the impact of some process parameters using designs of experiment (DOE). A link between process parameters and properties of these thin films is obtained using electrical, structural and diffusion characterization of the devices. Finally we propose hypothesis to explain observed phenomena and also some improvements to meet the challenges of this process.
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Synthesis and Ligand Engineering of Colloidal Metal Chalcogenide Nanoparticles for Scalable Solution Processed PhotovoltaicsRyan Gupta Ellis (9175325) 09 September 2022 (has links)
<p>As global population continue to
rise, the demand for energy is slated to increase substantially. To combat
climate change, large amounts of renewable energy will be needed to feed this
growing demand. Of renewable energy sources, photovoltaics are well positioned
to meet this increasing demand due to the immense abundance of solar energy
incident on earth. However, existing energy intensive, low throughput, and
costly manufacturing techniques for photovoltaics may pose a barrier to
continued large scale implementation.</p>
<p>Solution processing has emerged as
a promising photovoltaics fabrication technique with high throughput, high
materials utilization, and lower cost than existing vacuum-based methods. Thin
film photovoltaic materials such as Cu(In,Ga)(S,Se)<sub>2</sub> and CdTe have
both been fabricated using various solution processing methods. Of the various
solution processing routes, colloidal metal chalcogenide nanoparticles have
demonstrated promise as a hydrazine-free route for the solution processing of
high efficiency Cu(In,Ga)(S,Se)<sub>2</sub> solar cells. However, conventional
solution processing with colloidal nanoparticles has long suffered from anionic
and carbonaceous impurities, stemming from legacy synthesis methods. The work
in this dissertation aims to solve these issues through the development of
novel synthetic methods, ligand engineering, and ultimately improved
scalability through slot-die coating.</p>
<p> Typical colloidal syntheses rely on the use of
metal salts as precursors such as metal halides, nitrates, acetates, and so forth,
where the anions may incorporate and alter the electrical properties of the
targeted nanomaterials. In this work, the recent advances in amine-thiol
chemistry and its unique ability to solubilize many metal containing species
are expanded upon. Alkylammonium metal thiolate species are easily formed upon
addition of monoamine and dithiol to elemental Cu, In, Ga, Sn, Zn, Se, or metal
chalcogenides such as Cu<sub>2</sub>S and Ag<sub>2</sub>S. These species were
then used directly for the synthesis of colloidal nanoparticles without the
need for any additional purification. The metal thiolate thermal decomposition
pathway was studied, verifying that only metal chalcogenides and volatile
byproducts are formed, providing a flexible route to compositionally uniform,
phase pure, and anionic impurity-free colloidal nanoparticles including
successful syntheses of In<sub>2</sub>S<sub>3</sub>, (In<sub>x</sub>Ga<sub>1–x</sub>)<sub>2</sub>S<sub>3</sub>,
CuInS<sub>2</sub>, CuIn(S<sub>x</sub>Se<sub>1–x</sub>)<sub>2</sub>, Cu(In<sub>x</sub>Ga<sub>1–x</sub>)S<sub>2</sub>,
Cu<sub>2</sub>ZnSnS<sub>4</sub>, and AgInS<sub>2</sub>. </p>
<p>However, further impurities from deleterious carbonaceous
residues originating from long chain native ligands were still a persistent
problem. This impurity carbon has been observed to hinder grain formation
during selenization and leave a discrete residue layer between the absorber
layer and the back contact. An exhaustive hybrid organic/inorganic ligand
exchange was developed in this work to remove tightly bound oleyalmine ligands
through a combination of microwave-assisted solvothermal pyridine ligand
stripping followed by inorganic capping with diammonium sulfide, yielding greater
than 98% removal of native ligands via a rapid process. Despite the aggressive
ligand removal, the nanoparticle stoichiometry remained largely unaffected when
making use of the hybrid ligand exchange. Scalable blade coating of the ligand
exchanged nanoparticle inks from non-toxic dimethyl sulfoxide inks yielded remarkably
smooth and crack free films with RMS roughness less than 7 nm. Selenization of
ligand exchanged nanoparticle films afforded substantially improved grain
growth as compared to conventional non-ligand exchanged methods yielding an
absolute improvement in device efficiency of 2.8%. Hybrid ligand exchange
nanoparticle-based devices reached total-area power conversion efficiencies of
12.0%.</p>
<p>While extremely effective in ligand removal, ligand exchange
pathways increase process complexity and solvent usage substantially, which may
limit the cost advantage solution processing aims to provide. Further synthesis
improvement was developed through a ligand exchange free, direct sulfide capped
strategy. Using sulfolane as a benign solvent, CuInS<sub>2</sub> nanoparticles
with thermally degradable thioacetamide ligands were synthesized using thermal
decomposition of isolated metal thiolates from Cu<sub>2</sub>S and In
precursors. Through gentle thermal treatment, these ligands decomposed into
non-contaminating gaseous byproducts leaving carbon free nanoparticle films
without the need for ligand exchange.</p>
<p>With the development of virtually contamination free
colloidal nanoparticle inks, focus was shifted to scalability using slot die
coating. Unlike typical lab-scale coating techniques such as spin coating, slot
die coating is a widely used industrial coating technique with nearly 100%
materials utilization, and high throughput roll-to-roll compatibility. A custom
lab-scale slot-die coater was used to rapidly proof coating conditions, which
were rapidly analyzed for uniformity using absorbance scanning in conjunction
with profilometry. A cosolvent chlorobenzene/dichlorobenzene ink was developed
to yield highly uniform, crack free thin films from non-ligand-exchanged
Cu(In,Ga)S<sub>2</sub> nanoparticles, which were finished into devices with
champion total are efficiencies of 10.7%. To the best of our knowledge, this
represents the first report of slot die coated Cu(In,Ga)(S,Se)<sub>2</sub>
photovoltaics. The methods presented in this work offer a pathway towards low
impurity, high efficiency, scalable solution processed Cu(In,Ga)(S,Se)<sub>2</sub>
photovoltaics to enable low cost renewable energy.</p>
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