Modules with the silver-free contacts have already been certified, the company says.

“We apply the tin contacts on a full-faced aluminium rear side,” said D. Christian Buchner, who leads Schmid's cell business unit. "This closed layer improves rear side passivation which leads to an increase of cell efficiency by 0.2%.”

Schmid's TinPad systems can achieve silver savings of about three eurocents per cell for fast amortization time of the investment. On the specified aluminium paste the tin contacts can reach twice the peel off strength than required.

The TinPad is based on a technology under license from Schott Solar and was awarded the Intersolar Award 2012.