| Title: | 
        
            | Record cell efficiencies on mc-Si and a roadmap towards 20%, the EC project TOPSICLE | 
        
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            | Author(s): | 
        
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                Weeber, A.W.; Tool, C.J.J. ; Manshanden, P. ; Tathgar, O. ; Gjerstad, M. ; McCann, M. ; Raabe, B. ; Huster, F. ; Fath, P. ; Ponce-Alcantara, S. ; Coello, J. ; Canizo, C. del ; Roberts, S. ; Bruton, T.M. ; Heasman, K.C. ; Nagel, H. ; Lenkeit, B. ; Schmidt, W. ; Russell, R. ; Devenport, S. | 
        
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            | Published by: | Publication date: | 
        
            | ECN
                Solar Energy | 11-9-2006 | 
        
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            | ECN report number: | Document type: | 
        
            | ECN-RX--06-035 | Conference Paper | 
        
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            | Number of pages: | Full text: | 
        
            | 6 | Download PDF | 
    
    
        Presented at: 21st European Photovoltaic Solar Energy Conference and Exhibition, Dresden, Germany, 4-8 september 2006.
        
        
    
    
        Abstract:
        Record cell efficiencies were achieved with newly developed processes. An integral approach from wafer to module was used. Starting with high-purity feedstock, high-quality large-area mc-Si wafers were made and characterized. Initial lifetimes of up to 160 µs were observed. Three cell concepts were developed further to obtain high efficiency cells: 1) based on screen-printing and complete inline processing; 2) based on V-grooved texturing and roller printing; 3) based on a hybrid buried contact concept with screen-printed Al BSF. With advanced inline processing an independently confirmed efficiency of 17.0% was achieved on 156 cm2 mc-Si, which is a record for complete inline processing. A full size module made of cells processed with this process has a peak power of 94.3Wp, which corresponds to an encapsulated cell efficiency of 16.8%. Roller printing on V-grooved cells resulted in an independently confirmed efficiency of 17.2%. With the hybrid buried contact concept an efficiency, again independently confirmed, of 18.1% was reached on a cell area of 137 cm2; a record for this size. This record cell was used to determine a roadmap towards 20% mc-Si cell efficiency. For that, it is mainly needed to improve the rear side passivation and rear side internal reflection. This can be done with a di-electric layer for passivation and local contacts. Furthermore, the shading losses should be reduced with for example the Angled Buried Contact concept.
    
    
        
        
    
    
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