Czts thin film solar cells the science behind the research kesterite cu 2 znsns 4 czts materials have direct band gap energies ranging from 1. Czts also has near ideal properties for solar photovoltaics, as it is a very strong absorber and has a band gap of around 1. Kesterite cu2znsns4 czts, having only earthabundant elements, is a promising solar cell material. This aperture must be carefully centred to the beam intensity profile. Effects of compositional distribution on secondary phase. Zno and zns in czts solar cells electroplated czts solar cell achieve 5% efficiency with 20cm2 size. Request pdf on nov 1, 2014, md ibrahim khalil and others published czts layers for solar cells by an electrodepositionannealing route find, read and cite all the research you need on. Such cigs tandem solar cell devices showed improved efficiency up to 7. The first thing to consider in choosing the best possible solar cell is its efficiency in converting sunlight to electricity. Czts film contains neither rare metals nor toxic materials, and combined with the cadmiumfree buffer layer, we can expect solar cells with complete nontoxicity. Characterization of a czts thin film solar cell grown by. Preparation of solar cells the czts thin films were prepared by sulfurization carried out by heating the thin film precursors in h 2 s gas or s vapor. It provides a brief description of the development of czts thin film for solar cells, and surveys several methods of depositing czts films, then introduces the crystal structure of czts. A copper indium gallium selenide solar cell or cigs cell uses an absorber made of copper, indium.
Zn 1 x cd x s film can optimize the conduction band offset between cu 2 znsns 4 absorber and buffer, forming a minor positive conduction band alignment, thereby alleviating the recombination significantly and improving the. Since the discovery of its photovoltaic effect in 1966, cu2znsns4 czts has been widely studied for solar cell applications with the highest efficiency of 9. Cdfree cu2znsns4 solar cell with an efficiency greater than. However, the large open circuit voltage voc deficit remains the key concern. Kyosemi corporation, japan has developed sphelar, a spherical solarcell technology that captures sunlight in three dimensions. We report the performance of cu2znsns4 czts thin film solar cell that showed efficiency in the. To increase the performance of cztsbased solar cell, buffer layer optimization is still an obstacle. Growth of cztsbased monograins and their application to membrane solar cells 291. Over 9% efficient kesterite cu2znsns4 solar cell fabricated. Parameters used for the simulation of czts solar cell fto izno czts sns layer. Aug 26, 2015 conclusion in the czts solar cell development, significant progress on this relatively new research area has been achieved in recent years. Cdfree cu2znsns4 solar cell with an efficiency greater. Sputtering and pulsed laser deposition are typical vacuum techniques, which are employed for solar cell absorbers of. Here, we report a cdfree czts solar cell that exhibits 2019 energy and environmental science hot articles.
Czts is a promising photoabsorber as a photocathode for water reduction to produce hydrogen but its performance is often limited by the presence of a high concentration of defects. Sintered czts nanoparticle solar cells on metal foil nrel. Effects of compositional distribution on secondary phase and defect in czts thinfilm solar cell. A small, prototype solar cell that uses czts, a photovoltaic semiconductor that university of utah metallurgists produced in an old microwave oven that once heated student lunches. Numerical device simulation of carbon nanotube contacted czts. Mar 21, 2012 an electron microscopy image of a thin film solar cell based on the material cuin,gase 2 cigs is shown in fig.
This improvement is attributed to the better charge collection, which. Over 10 million scientific documents at your fingertips. The microstructure and chemical nature of the czts zto interface are carefully studied and the presence of an ultrathin zns, o tunnel layer is demonstrated. However, integrating czts with silicon is challenging due to siliconincompatible processing. Zinc tin oxide zto is a potential buffer layer for the czts photocathode as it has shown to be a good interface with czts and such cztszto solar cells have shown comparable efficiencies with the cztscds solar cells.
This may be caused by the recombination process at the contact back of the solar cell. Czts thin film, a potential candidate for application as absorber layer in thin film solar cells, has drawn much attention in these years due to its excellent photoelectric performance and nontoxic components. Copper zinc tin sulfidebased thin film solar cells. Although cds is the most commonly used composition as buffer layer and has. Impact of molybdenum out diffusion and interface quality. High efficiency cztsbased thin film solar cells are achieved by cation substitution and solgel method. Nanolayers of graphene and nanotubes have become the attractive materials as the front or back electrodes in thin film solar cells.
Growth of cztsbased monograins and their application to. Herman for lab access and resources brendan flynn for xrd and project guidance. Towards the development and fabrication of a lowcost. Device characteristics of cztsse thinfilm solar cells with 8. Controllable multinary alloy electrodeposition for thinfilm. Fabrication of cu2znsns4 thin film solar cells by sulfurization. We propose a novel thinfilm solar cell structure in which the traditional transparent conductive oxide electrode, zno. Copper zinc tin sulfide czts is a quaternary semiconducting compound which has received.
Ibm has an active research department in this area and recently announced a czts based solar cell that had a conversion efficiency of 11. Apr 27, 2016 unsw takes out czts efficiency world record. The microstructure and chemical nature of the cztszto interface are carefully studied and the presence of an ultrathin zns, o tunnel layer is demonstrated. Czts thinfilm solar cells were also fabricated and a highest efficiency of 4. A favorable band alignment is achieved using a 10 nm zn0. The solar cell efficiency in czts was increased to 5. The series resistance of a solar cell device depends on the quality of the tco layer, top electrode, and the electronic nature of the bottom mo czts contact wang et al. Modeling conductivity as a function of temperature for czts and cztse thin film solar cell absorber layers by melinda downs a senior honors thesis submitted to the faculty of the university of utah in partial fulfillment of the requirements for the. The processes of czts based solar cells can be divided into two categories. The low cost, environmental harmless cu 2 znsns 4 czts based thin film solar cells are fabricated by using abundant materials. Controllable multinary alloy electrodeposition for thin. An electron microscopy image of a thin film solar cell based on the material cuin,gase 2 cigs is shown in fig.
Considering that the difference between the two lies in the choice of the absorber material, the cause of the lower efficiency of czts. Construct a solar cell with czts continuously synthesized by the microreactor. This device, represented by more than 40 worldwide patents, comprises tiny silicon spheres. Czts thin films and the various properties of czts solar cells are described, specifically in the context of the conversion efficiencies of czts solar cells. Czts thin film solar cells institute for materials. Figure 3 shows tpv characteristics of the czts solar cell and estimated carrier lifetime plots. This improvement is attributed to the better charge collection, which may. Unsw takes out czts efficiency world record pv magazine. Device characteristics of cztsse thinfilm solar cells with 8 % conversion efficiency. The band alignment shows an offset between the top layer and the middle layer resulting in an electron blocking setup. Cu2znsns4 nanoparticulate thin films and their solar cell. Solution processing of cigs, czts and perovskite solar. Development of cztsbased thin film solar cells sciencedirect. The first thing to consider in choosing the best possible solar cell.
An overview of solar cell technology mike mcgehee materials science and engineering global climate and energy projectglobal climate and energy project center for advanced molecular photovoltaics precourt institute stanford university konarka nanosolar john benner provided the slides with the nrel logo. May 06, 20 a small, prototype solar cell that uses czts, a photovoltaic semiconductor that university of utah metallurgists produced in an old microwave oven that once heated student lunches. All constituents of this czts film, which are abundant in the crust of the earth, are nontoxic. Peter uhd jepsen dtu fotonik, ecthnical university of denmark 1. Towards highefficiency czts solar cell through buffer layer. Japans solar frontier, with ibm and tokyo ohka kogyo, have previously achieved 12. Numerical device simulation of carbon nanotube contacted. Modeling conductivity as a function of temperature for czts and cztse thin film solar cell absorber layers by melinda downs a senior honors thesis submitted to the. Band alignment of the proposed device is shown in the fig. Each of the first three quarters of the subcontract has been detailed in quarterly reports. Investigation of the snscu2znsns4 interfaces in kesterite. In cigs thinfilm solar cells, fewer secondary phases and defects form because of their superior phase stability, but in kesterite absorber layers. Theoretical simulation showsthat the stable chemical. 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 groundmount and rooftop installation.
Nevertheless, the impact of the sns secondary phase, which often forms alongside czts synthesis at high annealing temperature, on czts solar cells is poorly studied. Czts layers for solar cells by an electrodepositionannealing. The presence of the mos 2 layer at the interface between czts and mo back contact could also be responsible for high. Characterization of a czts thin film solar cell grown by sputtering. Pdf effect of czts parameters on photovoltaic solar cell from. Tpv characteristics of solar cells with 550 nm thick czts l ayer sulphurized at 500 c are given in fig. Champion efficiency of czts thin film solar cell tfsc has reached 8. Exploring cdfree buffer layer for czts photocathode for. Properties of high efficiency cigs thinfilm solar cells.
Shedding light on new frontiers of solar cell semiconductors. Properties of highefficiency cigs thinfilm solar cells kannan ramanathan, james keane, and rommel noufi national center for photovoltaics, national renewable energy laboratory, 1617 cole boulevard, golden co 80401. Here, substitution of cd improves the bulk quality of czts, resulting in a photocurrent enhancement of 4 ma cm. Czts was first created in 1966 and was later shown to exhibit the photovoltaic effect in 1988. The same group of researchers later on improved the efficiency of czts thin films based solar cell using similar approach to 1. Enhanced heterojunction interface quality to achieve 9. Figure 1 tem micrograph of solexants czts synthesized nanoparticles. In addition to the absorber and contact layers, electrical contacting is needed, either to contact individual cells or to form monolithically integrated. Device characteristics of cztsse thinfilm solar cells. This is the highest efficiency so far obtained for czts thin film based solar cell using wet chemistry silar technique. Czts solar cells absorbers produced by sputtering or. The czts films are uniform and compact on a microscopic scale, which translates to a benign photoresponse of the czts solar cell. Thickness optimization of various layers of czts solar cell. Impact of molybdenum out diffusion and interface quality on.
Electrodeposited czts solar cells from reline electrolyte. Cation substitution of czts solar cell with 10% efficiency ieee. Czts thin films were fabricated through sputtering from a quaternary cuznsns target, followed by a sulfurization process. Apr 14, 2016 a kesterite cu 2 znsns 4 thin film solar cell with efficiency of over 9% is obtained by utilizing zn 1 x cd x s film as a replacement to traditional cds buffer layer. Although cds is the most commonly used composition as buffer layer and has been an integral part of solar cells with record conversion ef.
Ito and nakazawa at shinshu university succeeded in fabricating the czts thin film by the atomic beam sputtering technique, and clarified that the optical band gap energy was near the optimum value of 1. Sce started to develop a spheral solar cell using metallurgical silicon of low purity. It has been found that obvious zn loss occurs during the sputtering and poorly crystallized czts are formed in the sputtered films. The czts film possesses promising characteristic optical properties. We also fabricated czts and cztsse solar cell units and investigated their electrical characteristics. Photovoltaic devices were prepared from the films and an efficiency of 3. Solution processing of cigs, czts and perovskite solar cells. Publishers pdf, also known as version of record link back to dtu orbit citation apa. An overview of solar cell technology stanford university. A thinfilm solar cell is a second generation solar cell that is made by depositing one or more. The proposed structure of czts solar cell ni has been used as a back contact material in this proposed czts solar cell structure. Thin film solar cells using earthabundant materials. However, the practical aspects of controlling deposit morphology and composition have not been significantly addressed because of the complex coplating variables that still need to be understood for multinary alloy ed.
Cu 2 znsns 4 czts based devices has become increasingly popular due to the better efficiency with different architectures for various types of solar cells. Cu2znsns4 czts quaternary compound has attracted much attention in the last years as new abundant, low cost and nontoxic material, with desirable properties for thin film photovoltaic pv applications. Czts solar cells absorbers produced by sputtering or pulsed. Czts solar cell characteristics at various sulfurization temperatures. Czts have three major advantages over the commercially available solar cells of today. Cts and czts for solar cells made by pulsed laser deposition and pulsed electron. The possible future prospects in the performance improvement of the czts based solar cell is analyzed in the present work with the. Each sphere functions as an individual, miniature solar cell 5. This cartoon view also shows the energy loss in a pn junction solar cell due to unabsorbed light, and excess. May 26, 2014 the same group of researchers later on improved the efficiency of czts thin films based solar cell using similar approach to 1. Nontoxic and cheap thinfilm solar cells for zeroenergy buildings worlds highest efficiency rating achieved for czts thinfilm solar cells. Currently czts sulfide absorbers for solar cells with the highest efficiency have all been produced by vacuum techniques which thus seem to be superior to solution processing for czts cells. Rhe resulting in a record half cell solar tohydrogen ef.
Czts layers for solar cells by an electrodeposition. Cu2znsns4 cztsbased solar cells show a promising performance in the. Here, we report a cdfree czts solar cell that exhibits an energy conversion efficiency of 10. Thin films of czts and czto for solar cells produced by. The technology is based on an array of single crystalline silicon spheres, each measuring 12 mm across, embedded in a transparent medium. In this work, czts thin films were grown using two different processes, based on vacuum deposition of precursors, followed by a heat treatment in sulphur atmosphere.
Cts and czts for solar cells made by pulsed laser deposition. Opportunities and technological challenges david mitzi mems dept. We confirm, by means of xray diffraction, raman scattering, and energy dispersive xray spectroscopy mapping, that this phase. Environmentally friendly earthabundant cdfree cu2znsns4 czts solar cells have recently achieved increasing power conversion efficiency by using znsno as the buffer layer.
Conclusion in the czts solar cell development, significant progress on this relatively new research area has been achieved in recent years. Cts and czts for solar cells by pulsed laser deposition and pulsed electron deposition rebecca bolt ettlinger november 14, 2016 phd thesis supervisor. Thickness optimization of various layers of czts solar cell jntm2014 h. Al, is replaced by a thin layer of singlewall carbon nanotubes bundle with a honeycomb network. Ultrathin cu2znsns4 solar cell prepared by pulsed laser deposition 96.