Day4 Energy and R&R achieve 19.3 percent module efficiency


The module combines Roth & Rau’s heterojunction technology, which was presented at the 26th EU PVSEC in Hamburg yesterday, with Day4’s DNA technologies.

The heterojunction technology is said to offer "superior" passivation properties, which lead to higher efficiencies and "very favorable" temperature behavior.

A pilot line for R&R’s 20 percent cells has been set up in Hohenstein-Ernstthal: the company claims the processes are being scaled up for mass production. In a statement, Day4 adds that R&R’s cell manufacturing process contains very few production steps and, as such, is both compatible with thin wafer technology, and cost-effective.

When combined with Day4’s DNA technology, says the company, efficiency losses from cell to module can be reduced and "substantial" silver paste consumption savings realized.

"Day4’s DNA Technology enabled fine line fingers of 70 micron width and 10 micron height resulting in a two percent short circuit current (Isc) gain and a 69 percent silver paste savings when used in the R&R Heterojunction cells," explained the statement.

It continued, "This innovation is a direct replacement of the conventional, high temperature solar cell soldering process and is comprised of a polymer film embedded with a number of copper wires specially coated with a proprietary, low-temperature melting point alloy.

"This establishes a low-resistance electrical contact with the surface of the PV cell creating over 2,100 independent electrical contacts."

A spokesperson for Day4 told pv magazine that the 19.3 percent efficiency has been verified by ISE CalLab. There are no announcements, however, they said, regarding further production.

The two parties have been working together for the last year.