Programm Photovoltaik Ausgabe 2008 ... - Bundesamt für Energie BFE
Programm Photovoltaik Ausgabe 2008 ... - Bundesamt für Energie BFE Programm Photovoltaik Ausgabe 2008 ... - Bundesamt für Energie BFE
Eidgenössisches Departement für Umwelt, Verkehr, Energie und Kommunikation UVEK Bundesamt für Energie BFE LARGE AREA FLEXIBLE CIGS Flexible CIGS solar cells on large area polymer foils with in-line deposition methods and application of alternative back contacts Annual Report 2007 Author and Co-Authors D. Brémaud, M. Kälin, A. N. Tiwari Institution / Company ETH Zürich Address Thin Film Physics Group, Technoparkstr. 1, 8005 Zürich Telephone, E-mail, Homepage +41 44 633 79 49, tiwari@phys.ethz.ch, http://www.tfp.ethz.ch Project- / Contract Number 100964 / 152404 Duration of the Project (from – to) 01.12.2006 - 28.02.2009 Date 31.01.2008 ABSTRACT Flexible Cu(In,Ga)Se2, called CIGS, solar cells are important for a variety of terrestrial applications. This project aims at the development of high efficiency flexible CIGS solar cells on large area (up to 30 x 30 cm 2 ) polyimide foils. All the component layers (Mo by sputtering, CIGS by evaporation, CdS by chemical bath deposition, ZnO/ZnO:Al by sputtering) of the flexible solar cells will be grown on inline moving substrates. The “home-build” CIGS and customised CdS deposition equipments will be improvised with emphasis on improving the performance, process reproducibility and large area inline deposition capabilities. A low temperature CIGS deposition process and controlled Na incorporation will be optimised towards developing 12% efficiency flexible solar cells with all in-line processes is still higher than the current state of the art of worldwide competing groups on this topic. Alternative electrical back contacts to conventional Mo will be developed on flexible polyimide foils. The deposition processes will be optimized for flexible CIGS solar cells on alternative back contacts and their advantages will be evaluated. The developed evaporators were evaluated in terms of evaporation profiles and layer thickness and composition across the substrate width were analysed. Reasonable homogeneity was obtained over a substrate width of at least 25cm. Further the chemical bath deposition equipment was redesigned for large area substrates and optimized for minimal waste products. Seite 75 von 288
Seite 76 von 288 Introduction / Project Goals The focus of this project is on up-scaling the deposition processes of flexible Cu(In,Ga)Se2, called CIGS, solar cells on polyimide foils with emphasis on improving the performance, process reproducibility and large area deposition capabilities. We have been developing deposition equipment for large area deposition of CIGS and CdS layers using our own designs. These in-house assembled equipments can accommodate substrate size up to 30 x 30 cm 2 , but the area of useful layers in terms of thickness and composition uniformity suitable for solar cell processing will be smaller because of the size of the deposition chambers. Several components of the CIGS deposition system, for example the crucially important linear evaporation sources and substrate heating and moving mechanisms, have been developed by our group through a project partly supported by the Swiss Federal Office of Energy (SFOE): Project Number 100964/151131 (FLEXCIM). One objective of the proposed project is to further improve the CIGS vacuum deposition equipment as well as the CdS chemical bath deposition equipment to develop solar cells on large area substrates and optimise a process for high efficiency and reliability. It is difficult to predict the efficiency potential of the in-house developed equipment but our endeavour will be towards 12% efficiency cells on in-line moving polyimide foils. This efficiency target is somewhat lower than our own world record of 14.1% achieved on a “small static deposition” equipment, but the 12% efficiency target is still higher than the current state of the art of worldwide competing groups on this topic. A second objective is to develop high efficiency flexible CIGS solar cells on polyimide foils coated with alternative electrical back contacts for CIGS instead of the well established Mo layers. There is three-fold motivation behind the development of flexible CIGS solar cells using alternative materials such as transparent conducting oxides as back contact: i) to overcome the performance instability problem associated with the oxidation of conventional Mo layer; ii) to provide multi-functionality in solar cell and for futuristic multi-junction (tandem) solar cells; iii) to reduce the thickness of the CIGS absorber by applying back contacts with higher reflectivity than of Mo layer. Successful development of highly efficient CIGS solar cells may solve the problems of degradation of the back contact in moisture, micro-cracking and de-lamination, especially in flexible cells, and open further possibilities for device engineering. Short description of the project The paragraph gives an overview of the equipment used for this project. Conventional vacuum in-line processing of large area solar cells requires mainly two kind of deposition equipment: � Sputter coating of front and back contact with inline moving mechanism. Sputtering technology is well established since many years and widely used for thin film deposition of metal and ceramic layers on any kind of substrates. For this project a refurbished production equipment from MRC (material research corporation), equipped with 3 linear magnetron targets for back contact deposition (Molybdenum, Indium-tin-oxide) and front contact (ZnO:Al) with a moving substrate carrier was tested for its homogeneity on 30x30cm 2 and used for processing, see Figure 1. � Thermal evaporator for the CIGS absorber layer with an inline sample moving mechanism. This kind of equipment is not yet commercially available as a packet. One of the most important aspects is the large area deposition uniformity achieved with the evaporators. Due to the growing interest in thin film photovoltaics evaporation source suppliers were attracted and start to develop solutions for this field. ETH has already developed large area sources for this application. Inline process control is further of crucial importance for reliable processing, See figure 1. Large Area Flexible CIGS, D. Brémaud, ETHZ 2/7
- Page 26 and 27: [26] H. Häberlin, L. Borgna, D. Gf
- Page 28 and 29: [89] Konzept der Energieforschung d
- Page 30 and 31: Solarzellen C. Ballif, J. Bailat, F
- Page 32 and 33: Département fédéral de l’envir
- Page 34 and 35: 3/9 Fig. 1: Refractive index n and
- Page 36 and 37: 5/9 V oc [mV] 940 920 900 880 860 8
- Page 38 and 39: 7/9 Fig. 5: Top) SEM micrographs of
- Page 40: 9/9 Acknowledgements The co-workers
- Page 43 and 44: Seite 40 von 288 Introduction and f
- Page 45 and 46: Seite 42 von 288 Introduction / Pro
- Page 47 and 48: Seite 44 von 288 Results The amorph
- Page 49 and 50: Seite 46 von 288 Collaborations IMT
- Page 51 and 52: Seite 48 von 288 Introduction / Pro
- Page 53 and 54: Seite 50 von 288 High efficiency so
- Page 55 and 56: Seite 52 von 288 Towards low costs
- Page 58 and 59: Eidgenössisches Departement für U
- Page 60 and 61: 3/6 The Athlet consortium comprises
- Page 62 and 63: 5/6 Large area cluster deposition s
- Page 64 and 65: SIWIS Département fédéral de l
- Page 66 and 67: 3/6 Results Defects characterizatio
- Page 68 and 69: 5/6 The test methodology was optimi
- Page 70: Département fédéral de l’envir
- Page 73 and 74: Seite 70 von 288 Summary of Applied
- Page 75 and 76: Seite 72 von 288 Table 5 summarizes
- Page 80 and 81: 3/7 Figure 1: Vacuum deposition equ
- Page 82 and 83: 5/7 Testing of thickness, chemical
- Page 84: 7/7 Figure 6: Large area flexible s
- Page 87 and 88: Seite 84 von 288 Introduction / Pro
- Page 89 and 90: Seite 86 von 288 Intensity / arb. u
- Page 92 and 93: LARCIS Eidgenössisches Departement
- Page 94 and 95: 3/6 Work and results Alternative Ba
- Page 96 and 97: 5/6 As expected the addition of Na
- Page 98 and 99: ATHLET Eidgenössisches Departement
- Page 100 and 101: 3/9 ZnO:Al/ZnO was deposited by rf-
- Page 102 and 103: 5/9 Figure 4: XRD pattern of powder
- Page 104 and 105: 7/9 PBDVA temp [°C] 100 200 250 Bu
- Page 106: 9/9 National and international coll
- Page 109 and 110: Introduction / Project Goals Thin f
- Page 111 and 112: Introduction The work to be reporte
- Page 113 and 114: Ongoing Work and Results 2007 Dye d
- Page 115 and 116: International Cooperation Internati
- Page 117 and 118: Introduction Dye-sensitized solar c
- Page 119 and 120: Figure 2: Upper panel: isodensity p
- Page 122 and 123: Eidgenössisches Departement für U
- Page 124: 3/3 (a) (b) I N ClO ClO4- 4- Al ITO
Eidgenössisches Departement <strong>für</strong><br />
Umwelt, Verkehr, <strong>Energie</strong> und Kommunikation UVEK<br />
<strong>Bundesamt</strong> <strong>für</strong> <strong>Energie</strong> <strong>BFE</strong><br />
LARGE AREA FLEXIBLE CIGS<br />
Flexible CIGS solar cells on large area polymer<br />
foils with in-line deposition methods and<br />
application of alternative back contacts<br />
Annual Report 2007<br />
Author and Co-Authors D. Brémaud, M. Kälin, A. N. Tiwari<br />
Institution / Company ETH Zürich<br />
Address Thin Film Physics Group, Technoparkstr. 1, 8005 Zürich<br />
Telephone, E-mail, Homepage +41 44 633 79 49, tiwari@phys.ethz.ch, http://www.tfp.ethz.ch<br />
Project- / Contract Number 100964 / 152404<br />
Duration of the Project (from – to) 01.12.2006 - 28.02.2009<br />
Date 31.01.<strong>2008</strong><br />
ABSTRACT<br />
Flexible Cu(In,Ga)Se2, called CIGS, solar cells are important for a variety of terrestrial applications.<br />
This project aims at the development of high efficiency flexible CIGS solar cells on large area (up to<br />
30 x 30 cm 2 ) polyimide foils. All the component layers (Mo by sputtering, CIGS by evaporation, CdS<br />
by chemical bath deposition, ZnO/ZnO:Al by sputtering) of the flexible solar cells will be grown on inline<br />
moving substrates. The “home-build” CIGS and customised CdS deposition equipments will be<br />
improvised with emphasis on improving the performance, process reproducibility and large area inline<br />
deposition capabilities. A low temperature CIGS deposition process and controlled Na incorporation<br />
will be optimised towards developing 12% efficiency flexible solar cells with all in-line processes<br />
is still higher than the current state of the art of worldwide competing groups on this topic.<br />
Alternative electrical back contacts to conventional Mo will be developed on flexible polyimide foils.<br />
The deposition processes will be optimized for flexible CIGS solar cells on alternative back contacts<br />
and their advantages will be evaluated.<br />
The developed evaporators were evaluated in terms of evaporation profiles and layer thickness and<br />
composition across the substrate width were analysed. Reasonable homogeneity was obtained over<br />
a substrate width of at least 25cm. Further the chemical bath deposition equipment was redesigned<br />
for large area substrates and optimized for minimal waste products.<br />
Seite 75 von 288
Change language