The strong demand for higher efficiency photovoltaic has recently attracted considerable interest in multi junction solar cells based on iiiv semiconductors 3. Awardwinning pv cell pushes efficiency higher news nrel. The variety of materials as well as an extensive technological toolbox has already led to the realization of diverse solar cell architectures. A latticematched ganpsi threeterminal tandem solar cell. We demonstrate the case for higher efficiencies achievable in gaas pin solar cells through embedded latticematched superlattices in the intrinsic region. The deficiency of high excess current in the bottom cell of the latticematched triplejunction solar cell can be partly reduced by implementing quantum wells qws into the middle cell. Multijunction solar cell an overview sciencedirect topics. Each materials pn junction will produce electric current in response to different wavelengths of light. Two and three terminal photovoltaic cells based on inp.
This paper presents results of attempts to grow qds in the gaas middle cell of lattice matched triple junction solar cells by metalorganic chemical vapor deposition mocvd. Triple junction solar cell design for low intensity low temperature space applications, 9th european space power conference, st. With a potential concentration ratio of 500 and double the. Commercialization of new latticematched multijunction. We have proposed the use of lattice matched ganpas on silicon for highefficiency multijunction. Iiiv multijunction solar cells royal society of chemistry. C, essentially equaling the performance of a latticematched 3junction cell with 39. As described above, lattice matched growth of a triple junction on ge substrates does not lead to an optimal split of the solar spectrum to the subcells. The use of ge is mainly due to its lattice constant, robustness, low cost. Dec 14, 2015 we demonstrate ge junctions grown by molecular beam epitaxy mbe for latticematched, fourjunction solar cells.
Latticematched ganpasonsilicon tandem solar cells ieee xplore. This research has produced a novel, realistically achievable, lattice matched, multi junction solar cell design with the potential to break the 50 percent power conversion efficiency mark under concentrated illumination, said robert walters, ph. I recommend this book to anyone with a particular interest in the lattice package or a general interest in r graphics. This paper proposes novel multijunction solar cell designs using latticematched iivi zncdmgsete and iiiv inalgaassb direct bandgap materials that can be grown on gasb or inas substrates. Latticematched and metamorphic gainpgainasge concentrator. To realize this, a fully functional threedimensional model of a lattice matched multi junction solar cell is required. To address the need for higher efficiency cpv cells, solar junction is currently manufacturing a latticematched multijunction solar cell that employs a 1 ev gainnassb bottom subcell in lieu of the traditional ge subcell. It is also noteworthy that the highest efficiency singlejunction solar cell is epitaxial gaas with 28. These can be realized by thin alternating layers of gaas y p 1y and ga x in 1x as figure 10 a 61. Theoretical isoefficiency surfaces and their projected contours for seriesconnected triple junction solar cells under the direct terrestrial solar spectrum at 500 suns concentration and 300k.
The aim of this chapter is to give an introductory overview of iiiv multijunction solar cells with a special emphasis on the origins of high efficiencies, the technological toolbox and some exemplary solar cell architectures. In this technical brief, we have set out the philosophy, including a brief incursion into economics, and our first results of dualjunction solar cells for high concentrator. The use of multiple semiconducting materials allows the absorbance of a broader range of wavelengths, improving the cells sunlight to electrical energy conversion efficiency. V solar cells solar cell materials wiley online library. Arto aho postdoctoral researcher member of research group. Then, multijunction cells such as monolithic multijunction solar cells and lattice.
To date, the world record 3 junction solar cell 43. This kind of solar cell structure has now reached its practical efficiency limit and went into production in 2010. Energy eng august, 2007 material development for improved 1 ev gain nas solar cell structures. Azur spaces current cpv product 3c40c is an advanced lattice.
Bandgap combinations of actual champion devices are also shown. Ge triple junction solar cells with higher efficiency and lower cost. This paper summarizes the stateoftheart of the lattice matched gainpgainasge triplejunction solar cell developed at the solar energy institute of upm iesupm. Lattice matched dilute nitride materials for iiiv highefficiency multi junction solar cells. Latticematched iiiv dualjunction solar cells for concentrations around suns j. Characteristics of high efficiency ingapingaas double. Nrl designs multijunction solar cell to break efficiency. Multi junction mj solar cells are solar cells with multiple pn junctions made of different semiconductor materials. Modelling of lattice matched dilute nitride 4junction.
The field of high efficiency inorganic photovoltaics pv is rapidly maturing in both efficiency goals and cover all cost reduction of fabrication. We have demonstrated a monolithic iiivonsilicon tandem solar cell in which most of the iiiv layers are nearly lattice matched to the silicon substrate. Device modeling of an optimized monolithic all lattice. Bandgap optimization of lattice matched triple junction. Multijunction mj solar cells are solar cells with multiple pn junctions made of different semiconductor materials. The tunnel junction design, based on an algaasgaas heterojunction, is found to be a key. The unique advantage of the dilute nitrides is that the bandgap and lattice constant can be tuned independently, allowing bulk material lattice matched to germanium or gaas over a wide range of bandgaps. Multijunction solar cells based on iiiv materials have achieved the highest. The 4junction solar cell has the following bandgaps. Harin ullal subcontract report nrelsr5200 54721 april 2012. Thats usually not a problem, but it would be an issue for this novel material, with the. Highefficiency multijunction solar cells are highly desirable for space and terrestrial applications.
Nrels pioneering multijunction work led to the solar junction sj3 solar cell with tunable bandgaps, latticematched architecture, and. This movpegrown device has achieved a record efficiency of 41. We at solar junction have adopted the dilute nitride material system to obtain these new bandgaps, and break through the 40% efficiency barrier. Sep 19, 2011 we at solar junction have adopted the dilute nitride material system to obtain these new bandgaps, and break through the 40% efficiency barrier.
In terms of threejunction cells, spectrolab supplanted the 1sun record efficiency for a solar cell with a latticematched gainpgainasge triplejunction cell of 32. Modeling latticematched inpbased multijunction solar cells. The favorable values in the table below justify the choice of materials typically used for multijunction solar cells. Institute of electrical and electronics engineers inc. I suggest that many users of lattice and most users of r probably ought to use lattice should buy this book. To address the need for higher efficiency cpv cells, solar junction is currently manufacturing a lattice matched multijunction solar cell that employs a 1 ev gainnassb bottom subcell in lieu of the traditional ge subcell. It can equally well serve the student as a learning tool on some of the basics of pv and the senior scientist in grasping the state of the art in specific areas of pvrelated knowledge.
The deficiency of excess current in the bottom cell of the latticematched triplejunction solar cell can be partly reduced by implementing quantum wells qws into the middle cell. High efficiency multijunction solar cells with finely. The top cell has an absorber of gainp 2, which has a bandgap of 1. Single junction ingaasp lattice matched to inp allows 0. A lattice matched ganpsi threeterminal tandem solar cell. This was accomplished with a triplejunction solar cell latticematched to inp. Low solubility of n in gap tolerance on the composition under the critical thickness. The current state of the art production solar cell for high concentration pv applications is a triple junction 3j cell, shown schematically in figure 1, with lattice matched layers throughout the device structure and containing a ge bottom cell. Lattice matched dilute nitride materials for iiiv high. A proposal of monolithicly integrated multijunction solar. Simulation of tunnel junctions alexandre walker modeling and simulation of iiiv semiconductor multi junction solar cells is invaluable to achieve higher efficiency devices. We have demonstrated a monolithic iiivonsilicon tandem solar cell in which most of the iiiv layers are nearly latticematched to the silicon substrate. The ge substrate, which is closely lattice matched with gaas, is commonly used as an infrared absorber to capture the radiation that passes through the gainp 2 gaas cell 43.
We demonstrate the case for higher efficiencies achievable in gaas pin solar cells through embedded lattice matched superlattices in the intrinsic region. Hcpv fundamentals sol ideas technology development. In the second stage, this approach will allow us to develop lattice matched gainp. We explore the potential for high efficiency multijunction solar cells that are not lattice matched to currently available single crystal substrates, but are still formed of component subcells that can be lattice matched to one another in the iiiv gainasp compound semiconductor material system. Figure 6 shows the process for a triplet mj cell for lattice matched top ingap. Different research topics tackled over the last years about this structure are described. We demonstrate ge junctions grown by molecular beam epitaxy mbe for latticematched, fourjunction solar cells. Rit has for the first time demonstrated mocvd based growth of lattice matched inalassb with sb content over 30%. Algainpge double junction solar cell with sb incorporation directly used for lattice matched. Latticematched multijunction solar cells based on dilute nitrides july 8, 2010 march 7, 2012 john herb solar junction san jose, california nrel technical monitor. Download citation modeling lattice matched inpbased multijunction solar cells currently, the multijunction solar cell structure gives the highest efficiency for photovoltaic solar cells.
Research photovoltaics and photonics research group dr. To address the need for higher efficiency cpv cells, solar junction is currently manufacturing a latticematched multijunction solar cell that employs a 1 ev. Latticematched and latticemismatched gainpingaasge triple junction solar cells are classic examples for gebased solar cells with. Therefore, monolithic multijunction solar cells have been largely studied recently. Incorporation of as in gapn low surface and interface roughness. Several approaches have already reached efficiencies higher than the latticematched triplejunction solar cell.
This paper proposes the use of a monolithically integrated back scattering layer to improve the efficiency of ultrathin gaas single junction solar cells. Lattice matched dilute nitride materials for iiiv highefficiency multijunction solar cells. A different composition of gainp, lattice matched to the underlying gainas, is utilized as the high energy junction gainpgainasge triple. Commercialization of new lattice matched multi junction solar cells based on dilute nitrides national renewable energy laboratory nr on. Germanium solar cells grown by molecular beam epitaxy for. Engineering the worlds most efficient solar cells spie. Commercialization of new latticematched multijunction solar cells based on dilute nitrides national renewable energy laboratory nr on. Multijunction mj solar cells use multiple semiconductor layers subcells to. Ultrathin gaas singlejunction solar cells integrated. These are first of all lattice matched compounds, which can be grown without strain.
Pdf latticematched multijunction solar cells employing a 1 ev. In this range, a lattice matched three junction cell with an in xal 1xas top subcell has a 56. Solar cell efficiency increase at high solar concentration. The efficiency of the cell as a function of temperature and concentration is described for both lattice matched lm and metamorphic mm triple junction solar cells. We have proposed the use of latticematched ganpas on silicon for highefficiency multijunction. Analysis and fundamentals, coauthored by greg smestad, is the first chapter in the newly released high concentrator photovoltaics fundamentals, engineering and power plants. Ganpas solar cells that can be latticematched to silicon. This solar cell has shown a 44% efficiency under 947 suns am1. Inpbased solar cells 11 have less application for multijunction solar cells since inp substrate is. The device consists of a doubleheterostructure gaasingap single junction solar cell integrated with a lattice matched znse layer etched as the back scattering layer coated with a highly reflective au film and flipchip bonded on. Development of the lattice matched gainpgainasge triple. Latticematched multijunction solar cells employing a 1 ev.
Terrestrial gainpgainasge 3junction cells have been produced at spectrolab with record efficiencies independently verified at nrel, of 31. In terms of three junction cells, spectrolab supplanted the 1sun record efficiency for a solar cell with a lattice matched gainpgainasge triple junction cell of 32. On one hand, knowhow from space industry in new solar cell design configurations and on the other, fabrication cost reduction challenges for terrestrial uses of solar energy, have paved the way to a new generation of pv devices, capable of. As described above, latticematched growth of a triple junction on ge substrates does not lead to an optimal split of the solar spectrum to the subcells. Using detailed balance calculations, the theoretical efficiency of three and four junction cells. These cells are inseries connected via tunnel junctions and the whole structure is illuminated at high solar irradiance, 14, and 16. Iiiv multijunction solar cells, as a new technology, offer extremely high efficiencies compared with traditional solar cells made of a single layer of semiconductor material. Inorganic photovoltaic solar energy can be somehow considered as heterodox among the available monographs on photovoltaics. Gainp gainas ge 3junction solar cell has been produced with 38. To realize this, a fully functional threedimensional model of a latticematched multijunction solar cell is required. High efficiency lattice matched fourjunction solar cells on gaas oral aho, a. Recent years have shown gainpgaas tandem solar cells with am0 sunlight incidence in space1. Both material systems have been studied in detail separately for different applications. Inpbased solar cells 11 have less application for multijunction solar cells since inp substrate is more expensive than ge.
Performance study of latticematched multijunction solar cells incorporating gainnassb junctions with 0. A different composition of gainp, lattice matched to the underlying gainas, is utilized as the high energy junction gainpgainasge triple junction photovoltaic cells. A iiiv triple junction latticematched onto gaas substrate has been for instance developed by solar junction. The wide bandgap inalassb topjunction is a novel solar cell material and was the key enabling technology. The tunneljunction design, based on an algaasgaas heterojunction, is found to be a key factor for achieving this efficiency at such high. Simulation of tunnel junctions alexandre walker modeling and simulation of iiiv semiconductor multijunction solar cells is invaluable to achieve higher efficiency devices. Device and material characteristics of galnp solar cells. These can be realized by thin alternating layers of gaas y p 1. In this paper, we report on the conversion efficiency improvement in in 0. Triplejunction iiiv based concentrator solar cells. Intermediate band solar cells using quantum dots qds have been proposed as an approach to increasing solar cell efficiency 1.
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