GaInP/GaAs/poly-Si Multi-Junction Solar Cells by in Metal Balls Bonding

In this study, a mechanical stacking technique has been used to bond together the GaInP/GaAs and poly-silicon (Si) solar wafers. A GaInP/GaAs/poly-Si triple-junction cell mechanically stacked using low-temperature bonding process which involves micro metal balls on line high-optical-transmission spin-coated glue material. Current–voltage measurements of cells have carried out at room temperature both in dark under 1 sun with 100 mW/cm2 power density simulator. The reached an efficiency 24.5% open-circuit voltage 2.68 V, short-circuit current 12.39 mA/cm2, fill-factor 73.8%. This study demonstrates great potential for micro-metal-ball achieve high conversion three or more junctions.