IMEC and Kaneka are claiming 22.68%efficiency from heterojunction silicon solar cells,using an electroplated copper contact grid on top of a transparent conductive oxide layer.
Normally,screen-printed silver is used for solar cell top contacts.
"A drawback of this technology is the difficulty to lower resistivity and to thin the metal line in silver screen printed contacts.As a result,efficiencies remain below optimal and cost remains relatively high,"said IMEC."Replacing the screen-printed silver with electroplated copper enables higher efficiencies and reduced fabrication costs."
For the demonstration 6in'semi-square'(rounded corner square)cells,the top electrodes were applied at Kaneka's Osaka lab using the firm's copper electroplating technology which is based on research at IMEC-Kaneka's European lab is at the IMEC campus in Leuven Belgium.
The result was certified by the German Fraunhofer ISE CalLab.
