A Comprehensive Perspective on the Fabrication of CuGaSe₂/Si Tandem Solar Cells

This review points out the current need for further research on tandem solar cells as the commercial single-junction solar cell technologies report close to their maximum performance limit. First, the conceptual insight and the desired interconnection schemes for tandem solar cells are briefly presented. Then, a comprehensive discussion on the structural, optical, and electronic properties of CuGaSe₂, evaluating its use as a top cell absorber material, is presented. Furthermore, the current status and the critical analysis of CuGaSe₂ solar cells, which finds that the adapted conventional device architecture possesses severe limitations, are presented. Based on the drawbacks of the existing materials in use, new materials to fabricate CuGaSe₂ solar cells are proposed. Also, tandem configurations with newly proposed CuGaSe₂ solar cell architecture by choosing Si photovoltaics as bottom cells are devised. In the end, further challenges in the devised tandem configurations with a focus on their band alignments are elucidated.