Effects Of Laser-Scribed Mo Groove Shape On Highly Efficient Zn(O,S)-Based Cu(In,Ga)Se-2 Solar Modules

In this work, the effects of the Mo groove (P1 line) shape on the quality and performance of final modules are investigated. A gradual sloped Mo edge is successfully realized by controlling the laser beam parameters and incidence directions. As a comparison, a sharp vertical Mo edge is also investigated. With the traditional sharp vertical groove shape, voids, cracks, and peel-offs near the abrupt step edge of P1 lines are often found to grow within the Cu(In,Ga)Se-2 (CIGS) layer and induce unwanted growth behavior of the transparent conducting oxide (TCO) layer. With the sloped groove shape, conformal growth with a continuous surface for CIGS, Zn(O,S) buffer, and Al:ZnO TCO layers without cracks and peel-offs at the P1 position from the ablated glass region to the pristine Mo region is successfully realized. The suppression of voids, cracks, and peel-offs in the CIGS layer effectively reduces the number of shunting pathways for the solar modules and helps to greatly improve the fill factor and efficiency of Zn(O,S)-based CIGS modules. Finally, a Zn(O, S)-based CIGS module of 16.3% efficiency is obtained with a cell width of 7 mm after use of MgF2 antireflective coating.