Metal pillar interconnection topology for bonded two-terminal multijunction III–V solar cells

Metal-interconnected multijunction solar cells offer one pathway toward efficiencies in excess of 50%. However, if a 3- or 4-terminal configuration is used, optical losses from the interfacial grid can be considerable. Here, we examine an alternative which provides an optimal interconnection for two-terminal bonded devices. This “pillar-array” topology is optimized by minimizing the sum of all power losses, including shadow losses and numerically computed electrical losses. Numerical modeling is used to illustrate the benefit of a pillar-array interfacial metallization for some 2-terminal configurations.