(Thanks to Atid-EDI) Yissum, the Research and Development Company of the Hebrew University of Jerusalem, has developed low-cost oxidation-resistant copper nano-inks. They can replace expensive silver inks that make up circuits in RFID-tags, solar cells, sensors and electrodes for displays.
http://www.businesswire.com/news/home/20140107005945/en#.UtwWJftBvIU