Download or read book Fabrication Of Cu2ZnSnSe4 Thin Film Solar Cells By A Two Stage Process written by Yejiao Wang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The properties of CZTSe thin-films and the performance of CZTSe thin-film solar cells have been characterized using techniques, including J-V, Raman spectroscopy, spectral response, and SEM/EDS. The best performance CZTSe thin-film solar cell that have been accomplished, has an open circuit voltage of 0.42 volt, shirt circuit current densities of 14.5 mA/cm2, fill factor of 47%, and efficiency of 2.86%.
Download or read book Fabrication of Cu2ZnSnSe4 Thin Film Solar Cells Using and Alloy based Processing Strategy written by Teoman Taskesen and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Film Solar Cells From Earth Abundant Materials written by Subba Ramaiah Kodigala and published by Newnes. This book was released on 2013-11-14 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fundamental concept of the book is to explain how to make thin film solar cells from the abundant solar energy materials by low cost. The proper and optimized growth conditions are very essential while sandwiching thin films to make solar cell otherwise secondary phases play a role to undermine the working function of solar cells. The book illustrates growth and characterization of Cu2ZnSn(S1-xSex)4 thin film absorbers and their solar cells. The fabrication process of absorber layers by either vacuum or non-vacuum process is readily elaborated in the book, which helps for further development of cells. The characterization analyses such as XPS, XRD, SEM, AFM etc., lead to tailor the physical properties of the absorber layers to fit well for the solar cells. The role of secondary phases such as ZnS, Cu2-xS,SnS etc., which are determined by XPS, XRD or Raman, in the absorber layers is promptly discussed. The optical spectroscopy analysis, which finds band gap, optical constants of the films, is mentioned in the book. The electrical properties of the absorbers deal the influence of substrates, growth temperature, impurities, secondary phases etc. The low temperature I-V and C-V measurements of Cu2ZnSn(S1-xSex)4 thin film solar cells are clearly described. The solar cell parameters such as efficiency, fill factor, series resistance, parallel resistance provide handful information to understand the mechanism of physics of thin film solar cells in the book. The band structure, which supports to adjust interface states at the p-n junction of the solar cells is given. On the other hand the role of window layers with the solar cells is discussed. The simulation of theoretical efficiency of Cu2ZnSn(S1-xSex)4 thin film solar cells explains how much efficiency can be experimentally extracted from the cells. - One of the first books exploring how to conduct research on thin film solar cells, including reducing costs - Detailed instructions on conducting research
Download or read book Copper Zinc Tin Sulfide Based Thin Film Solar Cells written by Kentaro Ito and published by John Wiley & Sons. This book was released on 2014-12-11 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with an overview and historical background of Copper Zinc Tin Sulphide (CZTS) technology, subsequent chapters cover properties of CZTS thin films, different preparation methods of CZTS thin films, a comparative study of CZTS and CIGS solar cell, computational approach, and future applications of CZTS thin film solar modules to both ground-mount and rooftop installation. The semiconducting compound (CZTS) is made up earth-abundant, low-cost and non-toxic elements, which make it an ideal candidate to replace Cu(In,Ga)Se2 (CIGS) and CdTe solar cells which face material scarcity and toxicity issues. The device performance of CZTS-based thin film solar cells has been steadily improving over the past 20 years, and they have now reached near commercial efficiency levels (10%). These achievements prove that CZTS-based solar cells have the potential to be used for large-scale deployment of photovoltaics. With contributions from leading researchers from academia and industry, many of these authors have contributed to the improvement of its efficiency, and have rich experience in preparing a variety of semiconducting thin films for solar cells.
Download or read book Thin Film Solar Cells written by Jef Poortmans and published by John Wiley & Sons. This book was released on 2006-10-16 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin-film solar cells are either emerging or about to emerge from the research laboratory to become commercially available devices finding practical various applications. Currently no textbook outlining the basic theoretical background, methods of fabrication and applications currently exist. Thus, this book aims to present for the first time an in-depth overview of this topic covering a broad range of thin-film solar cell technologies including both organic and inorganic materials, presented in a systematic fashion, by the scientific leaders in the respective domains. It covers a broad range of related topics, from physical principles to design, fabrication, characterization, and applications of novel photovoltaic devices.
Download or read book New Processing Approaches for Cu2ZnSnSe4 based Solar Cells written by Simón López Mariño and published by . This book was released on 2016 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present thesis focuses on the promising semiconductor material kesterite, Cu2ZnSn(S,Se)4, known as CZTS(e), which is used in the second generation of solar cells, generally known as thin film photovoltaics (PV). This material relies on earth-abundant, low-cost and low toxic elements which certainly attract the interest of both research community and industry. Kesterite could replace its well known and already commercialised thin film counterpart, CuIn(1-x)Gax(SySe1-y)2 (CIGS), since it has similar structural and optoelectronic properties and also cell architecture, but does not rely on scarce elements such as In and Ga. In order to achieve a commercial stage kesterite research needs to increase its still limited efficiency (12.6%), which is currently below the 15-18% required value. To achieve this goal, new tailored and customized processing solutions, dealing with major problems of this technology should be investigated and implemented. Moreover, increasing the potential market penetration of kesterite by diversifying its possible applications range can also be an appealing and interesting driver for the industry. This work focuses on the pure Selenium kesterite, CZTSe, using a versatile and simple sequential two step process to synthesize this absorber. Sputtering and reactive thermal annealing are the techniques chosen to produce CZTSe based solar cells. In addition, two different substrates were used, soda lime glass (SLG) and flexible and light-weight stainless steel (SS) foils. The thesis scope is divided into two interrelated parts: The first one deals with the proposal of novel and customized approaches to improve CZTSe-based devices performance, mainly using glass substrates. Three innovative processing solutions are developed, proven and included in this work. Two of them deal with the critic Mo back contact region and the third one focuses on the absorber surface. As a result, two original ways to control the decomposition of the back contact interface and the excessive generation of MoSe2 (overselenization) during the thermal treatment along with a chemical passivation route for the CZTSe surface are reported. Intermediate and thin i-ZnO layers and Mo multilayer configurations combined with nanometric MoO2 layers are introduced at the back interface. Likewise, KMnO4/H2SO4 + Na2S aqueous solutions capable of removing ZnSe while passivating the absorber surface are successfully implemented. The second part of this thesis focuses on the use of flexible and light-weight substrates alternative to conventional and rigid glass based ones. The use of these substrates add an extra value to the already mentioned advantages that kesterite accounts for. A biggest application niche, such as building integration photovoltaics (BIPV), portable consumer electronics, car chassis integration, space applications¿ etc., along with high throughput roll-to-roll (R2R) industrial manufacturing compatibility, could definitively ease kesterite commercialization. SS foils have been used successfully in this work, producing the first CZTSe flexible device ever reported in the literature. This thesis includes a detailed optimization of Cr impurity diffusion barriers and Mo back contacts in order to minimize the detrimental effects of metallic substrate impurities in the devices performance. Additionally, a comparison of different extrinsic alkali doping methods to effectively introduce Na and/or K in flexible and light-weight CZTSe solar cells is also reported. Na doped Mo targets (MoNa), SLG pieces introduced during the annealing, NaF and KF pre-absorber synthesis evaporation (PAS) and post deposition evaporation (PDT) were investigated. We report for the first time a detailed optimization for the use of MoNa layers combined with CZTS(e) technology. In regard to the K investigation, the work developed in this thesis can also be considered as pioneer in the field.
Download or read book Development of Cu2ZnSnSe4 Based Thin Film Solar Cells by PVD and Chemical Based Processes written by Markus Neuschitzer and published by . This book was released on 2016 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays mono- and multicrystalline silicon have the highest market share of all PV technologies but thin film solar cells based on CdTe or Cu(In, Ga)Se2 (CIGS) absorbers recently show promising high power conversion efficiency values and due to their short energy payback time, minimal use of high purity material and low cost, they attract more and more attention. However, one concern of thin film PV based on CdTe or CIGS is the use of scare elements like tellurium or indium and gallium which could become a bottleneck if the technology wants to scale up to the terawatt level. Therefore, there is a high interest to replace these scare elements by more abundant ones and find suitable earth abundant photovoltaic absorbers. Cu2ZnSnSe4 (CZTSe) or Cu2ZnSnS4 (CZTS) and its sulphur-selenide solid solution are promising candidates to replace CIGS as absorber material due to its composition of more earth abundant elements. In literature CZTSe and CZTS are referred to as kesterite due to its crystal structure. However, there is still a large gap between power conversion efficiencies of solar cells based on kesterite absorber material and more established thin film solar cells, thus intensive research is still necessary to close this gap. The main goal of this thesis was to develop and optimize heterostructure solar cells based on Cu2ZnSnSe4 absorbers, by cost effective physical vapour deposition (PVD) and chemical based processes. Special focus is put on an improved understanding of the influence of the surface properties of kesterite absorbers on device performance and furthermore to optimize the front interface, i.e. buffer layer as well as the kesterite absorber layer itself. A detailed study investigating the influence of the surface chemistry on device performance is presented. After a chemical etching to remove unwanted ZnSe secondary phases formed during CZTSe absorber synthesis a low temperature post deposition annealing at 200ðC of the full solar cell is necessary to improve device efficiencies from below 3% to over 8%. X-ray photoelectron spectroscopy (XPS) surface analysis showed that this post deposition annealing promotes the diffusion of Zn towards the surface and Cu towards the bulk resulting in a Zn enriched and Cu depleted surface region, which is crucial for high device performance. Additionally experimental surface treatments confirm the necessity of a Cu-poor and Zn-rich surface and the reason for this beneficial surface composition are discussed in detail. Furthermore, the CdS buffer layer which is typically used in kesterite based heterostructures solar cells was optimized and allowed improvements in device performance of 1% absolute. This optimization was further extended to Cd-free ZnS(O, OH) buffer layer. Efficiencies close to that of CdS reference solar cells could be achieved using optimized ZnS(O, OH) buffer layer. Additionally to the front interface optimization, a Ge assisted crystallization process for nanocrystalline CZTSe precursors was developed which largely increase grain growth and boost open circuit voltages (Voc) to promising high values due to the elimination of deep defects. Since the low Voc values is identified of one of the main bottlenecks of kesterite technology, the improvements achieved are highly promising and give important insight for further possible optimizations.
Download or read book Novel Two stage Selenization Methods for Fabrication of Thin film CIS Cells and Submodules Final Subcontract Report March 1 1993 March 31 1995 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the Phase 11 Final Technical Report of the subcontract titled[open-quotes]Novel Two-Stage Selenization Methods for Fabrication of Thin Film CIS Cells and Submodules.[close-quotes] The general objectives of the program are the development of a cost-effective, large-area process for CIS film deposition, optimization of the various layers forming the CIS device structure, and fabrication of high efficiency submodules using these optimized device components. During this research period, growth parameters of ZnO window layers were varied to optimize their electrical and optical properties. Investigation of the chemical interactions between the glass substrates, Mo layers and the selenization atmosphere revealed that the nature of the glass/Mo substrate greatly influenced the quality of the solar cells fabricated on them. Moderate amounts of sodium diffusing from the soda-lime glass substrate into the CIS film improved the efficiencies of the solar cells fabricated on such films. Mo layers allowing excessive Na diffusion through them, on the other hand, reacted excessively with the H[sup 2]Se environment and deteriorated the solar cell performance. Addition of Ga into the CIS layers by the two-stage selenization technique yielded graded absorber structures with higher Ga content near the Mo/absorber interface. Cu-rich CIS layers were grown with grain sizes of larger than 5[mu]m. In the Phase I Annual Report large area CIS submodules with efficiencies of about 3% were reported. During the present Phase II program 1 ft[sup 2] size CIS submodule efficiency was improved to 7%. Smaller area submodules with efficiencies as high as 9.79% were also fabricated using CIS layers obtained by the H[sub 2]Se selenization method. The processing yield of the devices based on a non-vacuum CIS deposition approach was improved and solar cells with efficiencies greater than 10% were fabricated.
Download or read book Novel Two stage Selenization Methods for Fabrication of Thin film CIS Cells and Submodules Annual Subcontract Report 25 March 1992 28 February 1993 written by and published by . This book was released on 1993 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the Phase 1 Annual Technical Progress Report of a subcontract titled {open_quotes}Novel Two-Stage Selenization Methods for Fabrication of Thin-Film CIS Cells and Submodules.{close_quotes} The objectives of the program are the development of a cost effective process for CIS film deposition, optimization of various layers forming the CIS solar cell and fabrication of submodules using these processes and devices. During this first phase of the program the authors have completed their 1 ft2 size processing capabilities and added to their facilities an in-line sputtering system that can handle up to 1 ft2 size substrates. They have optimized the sputtering conditions for the Mo contact as well as the Cu and In films. Thickness uniformity of the Cu and In layers have also been optimized by masking the magnetron cathodes to obtain a variation of 3% throughout a ft2 substrate. Using the resulting films, they have demonstrated their first large area CIS submodules with outputs of about 3W/ft2. Addition of a computer controlled mechanical scriber to the fabrication facilities, and optimization of the large-area ZnO layers are expected to improve the power output of these submodules to over 5W/ft2 shortly. In addition to the large-area submodule work, the authors have also carried out research aimed at the development of a non-vacuum processing approach for the growth of CIS layers. They have deposited films using this technique, and small-area cells with over 10% conversion efficiency have been demonstrated on such CIS layers.
Download or read book Fabrication of CIGS Absorber Layers Using a Two step Process for Thin Film Solar Cell Applications written by Harish Sankaranarayanan and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Devices with Voc's as high as 480 mV, Jsc's as high as 40.7 mA/cmp2.
Download or read book Growth and Characterisation of Cu In Ga Se2 Thin Films for Solar Cell Applications written by E. Ahmed and published by . This book was released on 1995 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fabrication and Characterization of Novel 2SSS CIGS Thin Film Solar Cells for Large Scale Manufacturing written by Keshavanand Jayadevan and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Metal induced Growth of Microcrystalline Silicon Thin Films for Solar Cells written by and published by . This book was released on 2005 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research focused on the process study for deposition of device quality polycrystalline silicon (poly-Si) thin films and solar cell fabrication by using a novel technique, metal-induced growth (MIG). Cobalt (Co) is introduced in the studies as a seed layer metal for the first time, while nickel (Ni) was another candidate. To grow the poly-Si, Co or Ni seed-layers were deposited on the foreign substrates by thermal evaporation with a few nm to 50 nm thickness. Substrates were transferred into the sputtering system for Si sputtering at elevated temperature from 525°C to 625°C. The Co or Ni reacted with sputtered Si to form metal disilicides which have very small lattice mismatch with Si (0.4% lattice mismatch for NiSi2 and Si, 1.2% lattice mismatch for CoSi2 and Si). The crystalline metal disilicides provide nucleation sites for poly-Si growth. With metal-induced growth, the relatively large-grain poly-Si films can be produced at relatively low temperatures on the various foreign substrates. Compared with Ni induced Si films, Co induced poly-Si has longer minority lifetime of 0.46 [mu]s as deposited and 1.3 [mu]s after annealing. A two-step sputtering method used for film deposition showed superiority over single step sputtering by achieving Si films with larger grain size (over 1 [mu]m) and less contamination. A double seed layer (5nm Co/50nm Ni) method was developed to produce the Si film with less Ni diffusion into Si. Metal-induced Si films were deposited on flexible thin tungsten substrates for solar cell fabrication. The good back Ohmic contact (metal disilicide) was formed naturally when the Si film was deposited. In this work, the solar cells were fabricated successfully by using metal-induced grown poly-Si. With the fabricated Schottky and P/N junction solar cells, the metal-induced growth processing parameters were studied. It was found that low-pressure sputtering, oxygen control during film growth, post-annealing and Si film hydrogenation are important to produce high quality poly-Si with fewer defects. The Schottky solar cell with optimized processing parameters showed the J[sub]sc and V[sub]oc of 12 mA/cm2 and 0.2 V, respectively. By passivating the MIG [mu]c-Si surface with hydrogenated nanocrystalline Si (nc-Si:H), the V[sub]oc was improved to 0.31 V. In addition, the current transport mechanism in Schottky and P/N junction devices were studied for different film growth conditions. The results showed that two-step sputtering, oxygen control and hydrogenation improved the quality of the Si film and devices.
Download or read book Fabrication and Characterization of Low Cost Solar Cells based on Earth Abundant Materials for Sustainable Photovoltaics written by Mahmoud Abdelfatah and published by Cuvillier Verlag. This book was released on 2016-07-08 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: The low cost and low temperature electrochemical deposition technique was employed to grow Cu2O thin films and ZnO:Al thin films were deposited by d.c. magnetron sputtering in order to fabricate solar cells. The potentiostatic and galvanostatic electrodeposition modes were used to deposit the Cu2O thin films. Raman spectra of thin films have shown characteristic frequencies of crystalline Cu2O. The contact between Cu2O and Au is found to be an Ohmic contact. The devices grown by a potentiostatic mode have higher efficiency than those grown by a galvanostatic mode. The optimum thickness of Cu2O thin films as an absorber layer in solar cells. was found to be around 3 µm respect to a high efficiency. Flexible and light weight solar cell was fabricated on plastic substrate.
Download or read book Printable Solar Cells written by Nurdan Demirci Sankir and published by John Wiley & Sons. This book was released on 2017-04-25 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: Printable Solar Cells The book brings together the recent advances, new and cutting edge materials from solution process and manufacturing techniques that are the key to making photovoltaic devices more efficient and inexpensive. Printable Solar Cells provides an overall view of the new and highly promising materials and thin film deposition techniques for printable solar cell applications. The book is organized in four parts. Organic and inorganic hybrid materials and solar cell manufacturing techniques are covered in Part I. Part II is devoted to organic materials and processing technologies like spray coating. This part also demonstrates the key features of the interface engineering for the printable organic solar cells. The main focus of Part III is the perovskite solar cells, which is a new and promising family of the photovoltaic applications. Finally, inorganic materials and solution based thin film formation methods using these materials for printable solar cell application is discussed in Part IV. Audience The book will be of interest to a multidisciplinary group of fields, in industry and academia, including physics, chemistry, materials science, biochemical engineering, optoelectronic information, photovoltaic and renewable energy engineering, electrical engineering, mechanical and manufacturing engineering.
Download or read book Thin Film Solar Cells written by Qiaoer Zhou and published by . This book was released on 2011 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Non vacuum and Low cost Techniques for Cu In Ga Se S 2 Thin Film Solar Cell Processing written by Christopher J. Hibberd and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar photovoltaic modules provide clean electricity from sunlight but will not be able tocompete on an open market until the cost of the electricity they produce is comparable to thatproduced by traditional methods. At present, modules based on crystalline silicon wafer solarcells account for nearly 90% of photovoltaic production capacity. However, it is anticipatedthat the ultimate cost reduction achievable for crystalline silicon solar cell production will besomewhat limited and that thin film solar cells may offer a cheaper alternative in the longterm. The highest energy conversion efficiencies reported for thin film solar cells have beenfor devices based around chalcopyrite Cu(In, Ga)(Se, S)2 photovoltaic absorbers. The most efficient Cu(In, Ga)(Se, S)2 solar cells contain absorber layers deposited by vacuumco-evaporation of the elements. However, the cost of ownership of large area vacuumevaporation technology is high and may be a limiting factor in the cost reductions achievablefor Cu(In, Ga)(Se, S)2 based solar cells. Therefore, many alternative deposition methods areunder investigation. Despite almost thirty companies being in the process of commercialisingthese technologies there is no consensus as to which deposition method will lead to the mostcost effective product. Non-vacuum deposition techniques involving powders and chemical solutions potentiallyoffer significant reductions in the cost of Cu(In, Ga)(Se, S)2 absorber layer deposition ascompared to their vacuum counterparts. A wide range of such approaches has beeninvestigated for thirty years and the gap between the world record Cu(In, Ga)(Se, S)2 solarcell and the best devices containing non-vacuum deposited absorber layers has closedsignificantly in recent years. Nevertheless, no one technique has demonstrated its superiorityand the best results are still achieved with some of the most complex approaches. The work presented here involved the development and investigation of a new process forperforming one of the stages of non-vacuum deposition of Cu(In, Ga)(Se, S)2 absorber layers. The new process incorporates copper into an initial Group III-VI precursor layer, e.g. indiumgallium selenide, through an ion exchange reaction performed in solution. The ion exchangereaction requires only very simple, low-cost equipment and proceeds at temperatures over1000?C lower than required for the evaporation of Cu under vacuum. In the new process, indium (gallium) selenide initial precursor layers are immersed insolutions containing Cu ions. During immersion an exchange reaction occurs and Cu ionsfrom the solution exchange places with Group III ions in the layer. This leads to theformation of an intimately bonded, laterally homogeneous copper selenide? indium (gallium)selenide modified precursor layer with the same morphology as the initial precursor. These modified precursor layers were converted to single phase chalcopyrite CuInSe2 andCu(In, Ga)Se2 by annealing with Se in a tube furnace system. Investigation of the annealingtreatment revealed that a series of phase transformations, beginning at low temperature, leadto chalcopyrite formation. Control of the timing of the Se supply was demonstrated toprevent reactions that were deemed detrimental to the morphology of the resultingchalcopyrite layers. When vacuum evaporated indium (gallium) selenide layers were used asinitial precursors, solar cells produced from the absorber layers exhibited energy conversionefficiencies of up to 4%. While these results are considered promising, the devices werecharacterised by very low open circuit voltages and parallel resistances. Rapid thermal processing was applied to the modified precursor layers in an attempt tofurther improve their conversion into chalcopyrite material. Despite only a small number ofsolar cells being fabricated using rapid thermal processing, improvements in open circuitvoltage of close to 150mV were achieved. However, due to increases in series resistance andreductions in current collection only small increases in solar cell efficiency were recorded. Rapid thermal processing was also used to demonstrate synthesis of single phase CuInS2from modified precursor layers based on non-vacuum deposited indium sulphide. Non-vacuum deposition methods provide many opportunities for the incorporation ofundesirable impurities into the deposited layers. Analysis of the precursor layers developedduring this work revealed that alkali atoms from the complexant used in the ion exchangebaths are incorporated into the precursor layers alongside the Cu. Alkali atoms exhibitpronounced electronic and structural effects on Cu(In, Ga)Se2 layers and are beneficial in lowconcentrations. However, excess alkali atoms are detrimental to Cu(In, Ga)Se2 solar cellperformance and the problems encountered with cells produced here are consistent with theeffects reported in the literature for excess alkali incorporation. It is therefore expected thatfurther improvements in solar cell efficiency might be achieved following reformulation ofthe ion exchange bath chemistry.
