Modeling and Optimization of a Novel Design of CIGS Tandem Solar Cells, Utilizing Mole Fraction Variation

• Main Authors: Filippou, Filippos, Michael, Sherif
• Format: Conference Proceeding
• Language: English
• Subjects: Copper; Design optimization; Gallium; Indium; Lattices; Optimization; Photovoltaic cells; Photovoltaic systems; Semiconductor device modeling
• ISSN: 2995-1755
• DOI: 10.1109/PVSC57443.2024.10749437

This study thoroughly explored the potential of a high efficiency multi-junction photovoltaic design comprising layers of Copper Indium Gallium Selenide (CIGS) solar cells. Leveraging the advanced design principles of tandem solar cells, the theoretical lattice match between semiconductors based on CIGS and the ability to tailor the energy gaps of each CIGS layer were the principal ideas that drove to the success of this research. Utilizing the Silvaco ATLAS simulation toolbox, an advanced virtual wafer-fabrication program, various physical models were simulated, and overall design optimization was conducted. Building upon prior research at the Naval Postgraduate School, which provided the background on modeling CIGS solar cells with Silvaco ATLAS and validating its results, two main models were simulated, exploring a triple-junction and a quad-junction tandem solar cell respectively. Optimization primarily involved adjusting the thicknesses and the mole fractions of the individual CIGS layers to match the corresponding generated currents while maximizing the output voltages. Results indicate promising performance for the triple-junction cell, achieving an efficiency of 27%, whereas the quad-junction cell reached lower standards, with an efficiency staying just below 19%. However, a notable drawback for both configurations was the necessity of significantly increasing the thickness of the bottom layers to enhance efficiency.