High-efficiency Thin and Compact Concentrator Photovoltaics using Micro-solar Cells with Via-holes Sandwiched between Thin Lens-array and Circuit Board

Abstract

We have developed a compact concentrator photovoltaic (CPV) module that comprises micro-solar cells with a cell size of ~ 0.6 mm × 0.6 mm, sandwiched between a 20 mm-thick lens array and a 1 mm-thick circuit board, with no air gap in the structure. To establish electrical connection between the circuit board and the micro-solar cells, we developed a micro-solar cell structure with via-holes through which the cathode and the anode on the upper face of the cell are electrically connected to electrodes patterned on the lower face of the cell. In this study, we demonstrated that the energy conversion efficiency of the micro-solar cell was close to that of a standard solar cell with dimensions ~ 5 mm × 5 mm, which is commonly used in conventional CPV systems. Our study shows that perimeter carrier recombination effects in micro-solar cells do not impact the performance significantly under concentrated illumination. We assembled our micro-solar cells into a CPV module and demonstrated the module energy conversion efficiency of 33.3% under solar illumination.