All-screen-printed 120-µM-thin large-area silicon solar cells applying dielectric rear passivation and laser-fired contacts reaching 18% efficiency

The market need for a lower price per Watt(peak) asks for the development of solar cell designs with a low production cost and a high performance. An approach to reach a high efficiency with a solar cell structure containing a diffused emitter on a p-type silicon wafer is the implementation of a PERC structure on the rear side [1]. This structure gets advantageous to the standard screen printed solar cell when its production cost stays comparable to the latter and offers a higher efficiency [2]. Since this technique can inherently be applied to thinner wafers, an additional advantage comes from the reduced material consumption. The purpose of this work is to introduce a production sequence able to create a PERC structure on thin silicon wafers using steps available in the PV industry or at least close to industrial application. Applying this process on Czochralski (Cz) wafers of 120 mu m thickness, a stable efficiency of 18.0 % was achieved.