Defects in Solar Cells and Devices


Shunts in silicon solar cells

O. Breitenstein, J. Bauer


Within the "SolarFocus" project and in bilateral cooperation with producers of solar cells, electrical shunts in silicon solar cells are investigated by thermal methods and SEM techniques. These shunts are internal short circuits limiting the efficiency of the cells, especially for low illumination intensities. Our main investigation technique is lock-in thermography, which allows to detect periodic temperature modulations below 10 ľK. Bright regions (red-yellow-white) in the lock-in thermograms are the shunt positions. The figure shows a lock-in thermogram of a 10cm x 10cm sized multicrystalline silicon solar cell measured under realistic operation conditions. The dominating shunts are lying at the outer edges of this cell, but also in the cell area some shunting regions appear.



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