Laser scribing of flexible thin film photovoltaic solar cells

Thin film solar photovoltaic cells, in particular based on Cu(In,Ga)Se2 (CIGS), have shown great promise with high photovoltaic efficiency at low material cost. Laser scribing has provided useful pathways in upscaling a unit cell into a module level of desired voltage and power outputs, taking advantage of layer specific absorption selectivity and reduced heat diffusion to the processing neighborhood. In particular, use of laser scribing technology is almost unavoidable to realize high-quality thin-film solar cells on flexible substrates. However, achieving high-efficiency CIGS solar cells on a flexible polymer substrate has been challenging due to thermally and mechanically weak nature of substrate material in combination with thin films. In this article, we present a review of our recent achievements in the area of flexible CIGS thin film solar photovoltaic module fabrication. Main focus is in understanding distinct laser scribing mechanisms for flexible substrate configurations, thereby presenting optimal processing parameters in conjunction with a new manufacturing approach of forming CIGS thin film architectures on thin polymer film coated glass substrate followed by a laser lift-off process for the ultimate flexibility.