Characteristics of Concentrator Triple Junction Cell Optimized for Current Matching

In the case of the triple-junction cell, in order to get maximum photo-current, current-matching for incident light by optimization of subcell thickness is important. At the concentrator application using lenses, the spectrum of concentrated light is different vastly from that of standard light, because of chromatic aberration. Therefore, it is also important to optimize the distance between lenses and the cell to get maximum photo-current. In this paper, we evaluated cell performance with different thickness of the top cell as a function of distance between the cell and lenses. The current result shows the structural change of the optical system affects significantly the performance of the system. And the triple-junction cell with top cell thickness optimized for AM 1.5 condition, photo-current of the top cell is equal to that of the middle cell, shows highest Isc and conversion efficiency under concentration at any concentration ratio