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Reverse Biasing in the Process of Annealling of Amorphous Silicon Solar Cells and Modules
K. Luczak, W. Grzesiak
Annealing, MotherPV Method, Amorphous Silicon (a-Si)
Thin Films
Subtopic: Amorphous and Microcrystalline Silicon
Event: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session: 3AV.1.33
2289 - 2291
ISBN: 3-936338-24-8
Paper DOI: 10.4229/23rdEUPVSEC2008-3AV.1.33
0,00 EUR
Document(s): paper


Reverse biasing has been found to be helpful in effective degradation recovery of amorphous silicon solar cells when strong light intensity is used as main factor during the annealing process. This paper reports the application of reverse biasing during low temperature annealing of triple junction amorphous silicon solar modules. The process of annealing was performed by application of small flat heaters above the surface of modules. This way a substantial degree of regeneration of degraded efficiency of modules can be achieved. The application of reverse biasing was expected to accelerate regeneration and to further increase the level of regeneration. However, contrary to these expectations reverse biasing has just an opposite effect. The process of regeneration of modules became slower and less efficient than without reverse biasing; as opposed to the situation in laboratory single junction solar cells. The difference in the structure of cells and modules seems to be responsible for the observed effect. It is now clear that field assisted defects recovery is not effective in triple junction modules and reverse biasing can not be applied whilst attempting to improve the regeneration process after degradation.