Multilayered structuring of thin-film PV modules by ultrafast laser ablation

• Few studies have investigated micromachining three thin-film layers.
• Removal of CIGS-based PV module thin-film layers can be predicted.
• EDS analysis confirms that the underlying layer is fully exposed.

Due to the growth of thin-film solar photovoltaic (PV) market for renewable energy sources, the development of versatile technique for scribing surface patterns with new record efficiency is crucial. This study presents an ultrafast-laser process for noncontact and chemical-free scribing of thin-film layers in CuInxGa(1−x)Se2 (CIGS)-based PV modules. The proposed ultrafast laser scribing process for single- and multiple-pass patterning was performed using an infrared laser system comprising a femtosecond laser source, galvano-mirror scanner, and high-precision motor driven stage. The interaction between laser beam and three thin films in CIGS-based PV modules was determined by investigating potential film-removal mechanisms, such as geometrical, thermal, mechanical, and optical properties. Well-defined grooves were successfully obtained on thin-film layers by applying pulse energies near the ablation threshold. The experimental results and numerical calculations show that the laser–material interactions indicate that the proposed surface-pattern technique is precise. The energy transfer between the laser beam and thin-film device was affected by introducing an electron–photon coupling variable. The study results show the surface-pattern characteristics of applying an ultrafast laser to thin-film PV modules under controlled process conditions.

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