This design allows cdte solar cells to be made thinner and more. The solar cell cds cdte obtained in our model has an open circuit voltage of 775 v and a maximum power point of 645 mv. Pv solar cells based on cdte represent the largest segment of commercial thinfilm. Solar cells of 79% efficiency were developed on sno x. The solar cell current source generates a light current iph. Preliminaries figure 1 shows schematic of ncdsp cdte solar cell devise structure used in the work, where h is the length of the cell, h e, the thickness of the emitter cds, h b the base cdte and w is the width of the depletion zone. Cigs solar cell on a flexible plastic backing and rigid cdte panels mounted on a supporting structure.
Cadmium telluride cdte institute of energy conversion. Thinfilm solar cells are finally becoming competitive. A screenprinted cds cdte solar cell was produced with improved preparation conditions for the carbon electrode, and the influence of the width of the cdte layer on the characteristics of the cell. Postdeposition processing options for highefficiency sputtered cds cdte solar cells naba r. As an absorber material for thinfilmbased solar cells, cdte holds the potentiality to fabricate highefficiency solar cells by means of lowcost technologies. Polycrystalline thinfilm cdtecds solar cells have been developed in a configuration in which a transparent conducting layer of indium tin oxide ito has been used for the first time as a back electrical contact on pcdte. Characterization of cadmium zinc telluride solar cells. Pdf high efficiency cdtecds thin film solar cell researchgate. In reality, siliconwafer cells achieve, on average, 15 to 25 percent efficiency. Global solar cell market size was estimated at 182. Presented at the 2006 ieee 4th world conference on photovoltaic energy conversion wcpec4 held may 712, 2006 in waikoloa, hawaii. Cadmium telluride cdte solar cells have quietly established themselves as a mass market pv technology. The first thinfilm technology to be commercialized was amorphous silicon on glass, which was used to power small electronic devices such as calculators.
Numerical simulation shows that the highest efficiency of singlejunction cdscdte solar cell equal to 18. A range of the deposition parameters is included in table 1. Considering that our pv panel should be able to charge a 12v battery to its maximum voltage of about 14v and the overall electrical current voltage characteristic of the photovoltaic generator therefore. Chu introduces a front window layer reducing the thickness of. University of toledo old dominion university robert collins sylvain marsillac this program has explored a number of novel materials for contacts to cdte solar cells in order to reduce the back contact schottky barrier to zero and produce an ohmic contact. Power conversion enhancement of cdscdte solar cell. Recognize the structure of cdte and cisg thin film cells as well as. May 01, 20 the most common semiconductors used in thinfilm solar module production are amorphous silicon asi, cadmium telluride cdte, and copper indium gallium diselenide cigs. Cadmiumtelluridematerial for thin film solar cells volume issue 10 dieter bonnet, peter meyers skip to main content accessibility help we use cookies to distinguish you from other users and to provide you with a better experience on our websites. The cell was calibrated by the national renewable energy laboratorys measurements and characterizations facility. If all of it was used to make solar cells, we could generate 0.
Due to their efficiency and relatively low manufacturing energy requirements, cdte solar cells had the shortest energy payback time among commercially relevant pv technologies. A thinfilm solar cell is a second generation solar cell that is made by depositing one or more thin layers, or thin film tf of photovoltaic material on a substrate, such as glass, plastic or metal. Despite the market remaining dominated by silicon, cdte now accounts for around a 7% market share 1 and is the first of the second generation thin film technologies to effectively make the leap to truly mass deployment. Cadmium telluride solar cells photovoltaic research nrel. Pdf a solar cell or photovoltaic cell is designed to convert sunlight into electrical energy through the photoelectric effect.
A novel structure of ultrathin cdte solar cells is proposed in this paper that focuses on conversion efficiency. Furthermore, thin film solar cells containing cadmium telluride hold a substantial advantage over conventional crystalline silicon solar cells. Thin film cds cdte solar cells has become one of the leading technologies for providing high power conversion efficiency at comparatively low manufacturing cost. The highest lab efficiency in thin film technology is 23. The layers succes sion and thicknesses are the one used in the present work. How do buffer layers affect solar cell performance and. It is mainly used as the semiconducting material in cadmium telluride photovoltaics and an infrared optical window. Pdf a solar cell is an electronic device which directly converts sunlight into electricity. For a device without cds layer, the reflectance spectrum indicates a bandgap of 1. The record efficiency for a laboratory cdte solar cell is 22. A solar cell is an electronic device which directly converts sunlight into electricity. 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.
Cdte solar cell in a novel configuration tiwari 2004. Cdte solar cells have the potential to undercut the costs of electricity generated by other technologies, if the opencircuit voltage can be increased beyond 1 v without significant decreases in. There are health concerns with the use of cadmium in thinfilm solar cells. Cadmium telluride pv is the only thin film technology with lower costs than conventional solar. In amorphous silicon solar cells, lightinduced degradation has a recoverable and a nonrecoverable component too, and the details of the. A simplified solar cell model and assumptions we consider a simpli. Numerical modelling of accharacteristics of cdte and cis.
Cis started evaporating at 600 oc, but only a 20% weight loss was measured at oc steinberger, 1997. Cdte solar panel manufacturers companies involved in cdte solar panel production, a key thinfilm panel technology. A big step forward in cost reduction is expected through the growth of solar cells. This is an important aspect to increase the specific power of cdte cds solar modules. Cdte thinfilm solar cells can be manufactured quickly and inexpensively, providing a lowercost alternative to conventional siliconbased technologies. After summarising the history of solar cells in chapter. Ion imppqgy p pglantation require energy to ionize the dopant. Durose 1 1stephenson institute for renewable energy and department of physics, school of physical sciences, chadwick building, university of. Construct a band diagram of the cdscdte solar cell. High efficiency solution processed sintered cdte nanocrystal solar cells. Thin film solar cells based on cdte cadmium telluride cadmium telluride is a material that is particularly well suited for thin film photovoltaics. Simulation of the efficiency of cdscdte tandem multi. The united states is the leader in cadmium telluride cdte photovoltaic pv manufacturing, and nrel has been at the forefront of research and development in this area.
Cdte solar panel manufacturers thinfilm enf company. Pdf cdte solar cells with opencircuit voltage breaking. The amount of cd in cdte solar cells is very small, and could be reduced even further as the cells become thinner. The role of back buffer layers and absorber properties for. Manufacturing cdte solar cell is cheaper due to its significantly low raw material consumption. Our results offer new research directions for solving persistent challenges of cdte photovoltaics. High efficiency cdte and cigs thin film solar cells. Rising penetration of renewable energy sources owing to environmental benefits coupled with increasing electricity demand is expected to propel market growth.
Cdte solar panels are now at parity with polycrystalline silicon for performance and cost. In addition to affecting the opencircuit voltage of a cell, it is commonly reported that buffer layers affect stressinduced degradation and transient phenomena in cdte and cuinse 2based solar cells. Cadmium telluride cdte has long been recognized as a strong candidate for thin film solar cell applications. The fact that a variety of deposition technologies can be used to fabricate ef. Fcoated glass substrates with a lowtemperature cdte photovoltaic solar cells has been regaining momentum in recent years, due to commercial advances made with regard to cdte technology. How do buffer layers affect solar cell performance and solar. Potential of cdte thin film solar cells for space applications. Buffer layers are commonly used in the optimization of thinfilm solar cells. Pv solar cells based on cdte represent the largest segment of commercial thinfilm module production worldwide. Presented at the 2006 ieee 4th world conference on photovoltaic energy conversion wcpec4. Small area laboratory devices have demonstrated ef. Semitransparent ultrathin cdte solar cells and durability. About 2,000 tons of cd is thrown away each year in the.
Other inexpensive solar cells are emerging with high potential such as those based on cuinalse 2. We have grown solar cells on 1 mm thick glass but they can also be grown on very thin 50100 m cover glasses while a low cost encapsulation or lamination can be applied to protect the back of the modules. Cds films have been prepared by chemical bath deposition and p. Finally, the paper presents the way forward with next generation cdte based solar cells utilising lowcost materials in their columnar nature in graded bandgap structures. Solar cells, covering single crystal, polycrystalline and amorphous materials utilising. This letter describes the fabrication and characteristics of high.
It is usually sandwiched with cadmium sulfide to form a pn junction solar pv cell. Design of a thin film cdte solar cell summary cadmium. Solar cell module efficiencies the record lab cell efficiency is 26. Cdte and cigs pv modules have the potential to reach. Solar photovoltaic pv cells san jose state university. Chin department of physics, apollo solar energy research center.
Cadmium telluride solar cellscadmium telluride solar cells. Pv array made of cadmium telluride cdte solar panels type of solar power cell cadmium telluride cdte photovoltaics describes a photovoltaic pv technology that is based on the use of cadmium telluride in a thin semiconductor layer designed to absorb and convert sunlight into electricity. Fraunhofer institute for solar energy systems, ise with support of pse. The melting point of cdte is 1041 oc, and evaporation occurs at 1050 oc in open air and at about 900 c under nonoxidizing conditions. This paper focuses on the role of the back contact barrier in increasing cell efficiency. At the same time, cdte module efficiency increased from 9% to 18%. Cdte solar cell has been stagnant for the last few years. Polycrystalline cdscdte solar cells al compaan distinguished university professor of physics, emeritus lecture for hebenellingson solar cells class mhmarch 15 201215, 2012 1. Postdeposition processing options for highefficiency.
This work involves characterization of cadmium zinc telluride films and solar cells prepared by close spaced sublimation. High efficiency solution processed sintered cdte nanocrystal. Electronic properties of cdte cds solar cells as influenced by a buffer layer y. Cadmium telluride was originally considered for thin film solar cells because of its optimum band gap, high optical absorption coefficient and ability to be doped. The research on thin film cdte photovoltaic solar cells has been regaining momentum in recent years, due to commercial advances made with regard to cdte technology. Despite the market remaining dominated by silicon, cdte now accounts for around a 7% market share and is the first of the second generation thin film technologies to effectively make the leap to truly mass deployment.
An overview of solar cell technology stanford university. Optimization of electrics parameters cdscdte thin film. Cdte solar cells with opencircuit voltage breaking the 1 v. High efficiency cdte and cigs thin film solar cells nrel. We have done modeling and simulation of thin film cds cdte solar cell and then used. A thin film solar cell is a second generation solar cell that is made by depositing one or more. The study is carried out by simulation with scaps solar cell capacitance simulator whose mathematical model is based on solving the equations of poisson and continuity of electrons and holes.
Many of the topics that are discussed in this book are also covered in the massive open online course mooc on solar energy delftx, et. The institute of energy conversion iec has been involved in research and development of group iivi semiconductor thin film photovoltaic devices since its founding in 1972. Cost of power to be further reduced through performance increases and improvements in cell structure or processing. Exploring back contact technology to increase cdscdte solar. A high efficiency ultrathin cdte solar cell for nanoarea. Simulation and performance study of nanowire cds cdte solar cell. Solar cell market size, share industry report, 2022. Optimum cell performance is usually found when the tco layer in contact with the cds is very resistive or almost insulating. We see that cuingase 2 and cdte based solar cells have achieved efficiencies above those for asi cells. These cells produce lowcost electricity by absorbing sunlight at nearly the ideal wavelength. Doping of polycrystalline cdte for highefficiency solar.
Fabrication of cdscdtebased thin film solar cells using. Pdf cadmium telluride is a promising photovoltaic material for thinfilm solar cells. Pdf simulation and performance study of nanowire cds. The iiiv semiconductor compound, cdte, has suitable electrical and optical properties as photovoltaic and highenergy radiation sensor material.
However, in the past decades, the opencircuit voltage has stagnated at around 800900 mv. This structure achieved by rotating 90o in the base line structure that suggests high efficiency due to the high current density. The best efficiency results reported for three of the more relevant thinfilm solar cell technologies are summarized in table 1 green et al. The cell was calibrated by the national renewable energy laboratorys. Cdte thickness a cc b d normalizedcell performanceparameters of four differentcdte thickness solar cells. Figure out the difference of mono and polycrystalline silicon solar cell. At the manufacturing front, the cdte technology is fast paced and moving forward with usbased first solar inc. Life cycle impact analysis of cadmium in cdte pv production pdf. Currently, first solar has announced a new world record this year for cdte pv solar cell efficiency of 17. Production method for cdte solar cells in substrate. The controlled doping of cdte with cu leads to increased hole density, enhanced carrier lifetime and improved carrier collection in the solar cell. Performance cdte solar cells university of illinois angus rockett copis.
About 20,000 tons of cd are used worldwide each year, about half for nicd batteries. This process requires firstly, a material in which the absorption of light raises an electron to a higher energy state. Optimization of electrics parameters cdscdte thin film solar. Study of efficiencies cdtecds photovoltaic solar cell. Leaching of cadmium and tellurium from cadmium telluride. Numerical simulation shows that the highest efficiency of singlejunction cds cdte solar cell equal to 18. These devices could absorb uv, visible and ir radiation from the solar spectrum and combine impact. Concentrator solar cells expense of multijunction cell.
Cdte solar cells have the potential to undercut the costs of electricity generated by other technologies, if the opencircuit voltage can be increased beyond 1 v without significant decreases in current. Cadmium telluride cdte is a stable crystalline compound formed from cadmium and tellurium. The result showed a considerable improvement over the 15% efficiency of the reference solar cell. Cadmiumtelluridematerial for thin film solar cells. Pdf simulation of cadmium telluride solar cells structure. In the article, we shall study the temperature and dopinglevel dependence of cdte solar cell performance including excitons with the modi.
A study has been made to improve the efficiency of. The primary routes for increasing cds cdte solar cell efficiency involve increasing free carrier density, reducing bulk and interface recombination, andor reducing back contact barrier height. The efficiency of cdte solar cells has reached just more than 15 percent, and cigs solar cells have reached 20 percent efficiency. Light soak stress of bare cdscds cdte cdte cells vs. Czt is deposited by cosublimation of cdte and znte. S1 supporting information the role of back buffer layers and absorber properties for 25% efficient cdte solar cells geethika k. Numerical modelling of accharacteristics of cdte and cis solar cells alex niemegeers and marc burgelman department of electronics and information systems elis, university of gent, gent, belgium. An electronic solar cell model can be considered, as shown in figure 5b, taking into account the effect of the series resistance rs and shunt resistance rsh.
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