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Metallic impurities are detrimental to many silicon devices and limit the efficiency of multicrystalline silicon solar cells. Therefore they are a major subject of ongoing research. Photoluminescence spectroscopy is a promising technique for detecting precipitated metals in silicon because of its sensitivity to the minority carrier density and to specific types of defects; however the impact of impurities on the defect luminescence could not be clarified yet. In this letter we examine the role of micron‐sized iron and copper precipitates in direct bonded wafers by micro‐photoluminescence spectroscopy. Both kinds of precipitates are detectable by means of the reduced band‐to‐band luminescence. An element‐specific effect on the defect luminescence is observed. The results are confirmed by X‐ray fluorescence spectroscopy. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)