Multi-junction cell PV

Multi-junction cell design involves superposing several cells in a stack. In the case of two cells, it will form a double junction, also called a tandem cell. Stacking more cells together forms a triple or a quadruple junction. In all cases, the upper cell(s) must be as transparent as possible to enable the lower cells to still be active. This approach enables a broader spectrum of sunlight to be captured, and overall efficiency to be increased. III-V multi-junction cells using elements in the III and V columns of the periodic table, such as gallium indium phosphate (GaInP), gallium indium arsenide (GaInAs), and gallium arsenide (GaAs), are often used for concentrated PV applications.