Colorful, Flexible, and Lightweight Cu(In,Ga)Se2 Solar Cell by Lift-Off Process With Automotive Painting

We developed a simple lift-off process for producing colorful, flexible, and lightweight Cu(In,Ga)Se2 (CIGS) solar cells. The developed lift-off process consists of three steps: first, attaching a plastic film on a CIGS/glass solar cell at the temperature of around 100 °C; second, scribing the cell to the desired area/shape after cooling down; and finally, a back contact is deposited on detached layers. The major advantage of the lift-off process is that the CIGS layer can be grown under high temperature, which is in contrast to the direct growth of CIGS cells on plastic films. Our measurements show that the fabricated lift-off cells have nearly identical performance compared to that of the cell before the lift-off process, suggesting the validity of the developed lift-off process for producing flexible and lightweight CIGS solar cells. The colors were generated on the cells by coating the highly transparent automotive paint on the plastic films. The glass-flake pigments were found to exhibit bright, uniform, and solid appearance on the flexible CIGS solar cells with small output power reduction of less than 5% compared to the cells before the lift-off process for chromatic colors.