Kaneka and imec report a large area (6-inch semi-square) heterojunction silicon solar cell with a certified power conversion efficiency of 22.68%. The cell has an electroplated copper contact grid on top of the transparent conductive oxide layer.
To realize the top grid electrode in heterojunction silicon solar cells, silver screen printing is the preferred technology in the photovoltaic system industry. A drawback of this technology, however, is the difficulty to lower resistivity and to thin the metal line in silver screen printed contacts. Replacing the screen-printed silver with electroplated copper helps overcome the disadvantages of silver screen printing, enabling higher efficiencies and reduced fabrication costs.
Kaneka’s Photovoltaics European Laboratory is located at the imec campus in Leuven, Belgium. The development of large area Cu-plated heterojunction silicon solar cells is a step towards a fab-compatible process on large area module integrated solar cells.