High speed structuring of CIS thin-film solar cells with picosecond laser ablation

Thin film solar cells have shown a big potential to decrease cost of manufacturing for photovoltaic power generation. Despite of all research attempts to optimize materials and efficiency the mass production of thin film solar cells is still employing some mechanical steps of structuring, where thin films with a thickness of approximately 1 mu m are selectively separated for the monolithic serial interconnection. Here we show the structuring of CIS (CuInSe2) thin films solar cells by picosecond laser ablation. We used a new method, which we called " directly induced laser ablation" to increase process speed for the scribing of a Mo-film on glass (pattern 1, P1) to 4000 mm/s with an elliptically shaped beam. Directly induced laser ablation exhibits a non thermal behaviour. Standard laser ablation was used to create P2 and P3 lines at a process speed up to 200 mm/s. All processes showed their functionality for a complete interconnected solar module.