High Performance CIGS Thin-Film Solar Cells: A Laboratory Perspective

We present a summary of our work on the preparation of CuInGaSe2 (CIGS) absorbers that has led to fabricating record-efficiency solar cells. The use of the three-stage process in conjunction with composition monitoring facilitates the fabrication of solar cells with efficiencies between 18% and 19.5% for absorber bandgap in the range of 1.1-1.2 eV. We describe our recent results in reducing absorber thickness and low-temperature deposition. Our preliminary results on absorbers grown from low-purity source materials show promise of reducing the cost of fabricating the absorber.