Laser-based series interconnection of chalcopyrite und perovskite solar cells: Analysis of material modifications and implications for achieving small dead area widths

Abstract

Both nanosecond pulses and picosecond laser pulses are used for P2 patterning of chalcopyrite (Cu(In,Ga)Se2, CIGSe) and metal halide perovskite solar cell absorber layers. For CIGSe, the range of the modified material visualized by photoluminescence imaging is significantly wider than the actual physical linewidth, since energy input by the laser pulses leads to material modification in the vicinity of the scribed lines. This effect does not occur with the perovskite absorber layers, where there is no apparent influence on the edge regions. From numerical calculations of the temperature depth-profiles and the surface temperature distributions it is concluded that this effect is due to the significantly lower perovskite absorber layer thickness compared to CIGSe and the nevertheless significantly higher laser fluence required for perovskite ablation. The unaffected edge regions around the P2 line in the perovskite enabled a reduction of the dead area width in the fabrication of 3-segmented mini-modules, which could be significantly reduced from 430 to 230 µm, while increasing the aperture area power conversion efficiency and also the geometric fill factor, which could be increased up to 94.6%.