Ag nanoparticles can be successfully used instead of Pd, which is an expensive metal, as novel activators for electroless copper deposition (ECD). The analytical results obtained using electrochemical quartz crystal microbalance measurements and mixed potential theory illustrate that the activity of Ag nanoparticles can be enhanced by adding 2,2'-bipyridyl to the ECD bath. The results of a previous study on Ag nanoparticles in a simple ECD bath showed that the nanoparticles were inactive. In contrast, the results of this study demonstrate that the addition of 2,2'-bipyridyl can improve the deposition current density by about 0.004 mA cm(-2) and help to achieve a deposition rate of 33.9 mu g cm(-2) s(-1). (C) 2011 Elsevier Ltd. All rights reserved.