Picosecond-Laser Structuring of Thin Films for CIGS Solar Cells

Interest in complex multilayered CuIn x Ga (1-x) Se 2 solar cells has increased recently because of unique combination of factors such as low manufacturing cost and high photovoltaic conversion efficiency. The efficiency of the thin-film solar cells with a large active area might be maintained making series interconnects in order to reduce photocurrent in thin films and resistance losses. Laser technologies are a promising method to accomplish the scribing processes. Lasers with the picosecond pulse duration were applied in structuring of conducting, semi-conducting and isolating films in the complex multilayered Cu(InGa)Se 2 (CIGS) solar cells deposited on the polyimide substrate. The selective removal of ITO and CIGS layers was achieved with the 355 nm irradiation without a significant damage to the underneath layers in the ITO/CIGS/Mo/PI solar cell system. The 355 nm wavelength was also found to be favorable for the absorber film scribing process in the ZnO/CIGS/Mo/PI solar cell system. High repetition rate picosecond lasers with a short pulse duration offer new possibilities for high quality and efficiency scribing.