The Effect of Adsorbent Layer Thickness and Gallium Concentration on the Efficiency of a Dual-Junction Copper Indium Gallium Diselenide Solar Cell

Abstract

The split of the sunlight spectrum by the bandgap energy of multi-junction solar cells is a highly effective way to increase solar cell efficiency. The reason is that the energy of photons is effectively absorbed, and there is a reduction in solar cell loss. In this contribution, we report on the performance of a doublejunction copper gallium diselenide/copper indium gallium diselenide (CGS/ CIGS) solar cell with a cadmium sulfide (CdS) buffer layer simulator. The J–V characteristics and the external quantum efficiency were simulated under AM1.5 illumination. Increased efficiency was seen as a result of the change in the thickness of layers and different molar ratio amounts of gallium, and the optimal amount of each factor was obtained. In this study, a single CGS solar cell was used as the top cell and a single CIGS solar cell as the bottom cell in the tandem configuration, which showed conversion efficiencies of 16.175% and 15.696%, respectively. Finally, solar cell efficiency of 32.3% was obtained in the double-junction state, an increase of 6% compared with the reference cell.