ECN publication
Title:
High efficiency industrial screen printed n-type solar cells with front boron emitter
 
Author(s):
Mihailetchi, V.D.; Komatsu, Y.; Coletti, G.; Kvande, R.; Arnberg, L.; Knopf, C.; Wambach, K.; Geerligs, L.J.
 
Published by: Publication date:
ECN Solar Energy 13-12-2007
 
ECN report number: Document type:
ECN-M--07-115 Conference Paper
 
Number of pages: Full text:
5 Download PDF  

Presented at: 33rd IEEE Photovoltaic Specialists Conference, San Diego, USA, 11-16 mei 2008.

Abstract:
There is currently much interest in n-type base cells because of potential advantages, both of silicon base material and of cell process, for high efficiency. We present results of n-base solar cells on large area multicrystalline and monocrystalline silicon wafers, produced using simultaneous diffusion of phosphorus back surface field and boron emitter, screen-printed metallization and firing through. The cell process leads to record high efficiencies of 16.4% on mc-Si and 18.3% on monocrystalline wafers. We also consider material-related cell characteristics. It is experimentally demonstrated that in mc-Si a low resistivity is correlated to reduced cell efficiency, with the optimum base resistivity lying between 1.5 and 4 Ohm-cm. By characterising and modeling cells from monocrystalline Si, from nominally clean mc-Si, as well as from intentionally Fe-contaminated mc-Si, the impact of the mc-Si wafer purity on emitter properties is investigated in more detail.


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