AlGaAs/Si dual-junction tandem solar cells fabricated by epitaxial lift-off and print transfer-assisted bonding

Tandem solar cells using different bandgap materials provide higher energy conversion efficiency than single junction cells. However, the need for current matching and lattice matching often restricts the material selection for multi-junction solar cells. To overcome these challenges, we report AlGaAs/Si dual-junction tandem solar cells fabricated by a combined epitaxial lift-off (ELO) and print-transfer method without adhesive layers. Compared to the stacking methods with epoxies, light scattering as well as the need for heat management are avoided here. Furthermore, the epitaxial lift-off approach can help save substrates for re-use and thus is promising to lower the cost of photovoltaic panels.