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

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 CuIn_xGa_(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.