On the detection of shunts in silicon solar cells by photo‐ and electroluminescence imaging

Recently electroluminescence (EL) and photoluminescence (PL) imaging were reported to allow detection of strong ohmic shunts in silicon solar cells. Comparing lock‐in thermography (LIT) images with luminescence images of various shunted cells, measured under different conditions, the ability of luminescence techniques for shunt detection is investigated. Luminescence imaging allows identifying ohmic shunts only if they reach a certain strength. The detection limit for PL measurements of linear shunts was estimated to be in the order of 15 mA at 0·5 V bias for a point‐like shunt in multicrystalline (mc) cells. Pre‐breakdown sites can also be detected by electroluminescence under reverse bias.