Flexible InGaP/(In)GaAs tandem solar cells with very high specific power

In this work, we demonstrate a new scheme for realizing flexible double-junction InGaP/(In)GaAs tandem solar cells with very high specific power of ~2000W/kg at one sun intensity. The controlled spalling technique is employed because of its simplicity to separate the solar cell structure from the growth substrate. Furthermore, the entirety of the elements used for the layer transfer process is incorporated in the final device structure. The combination of our new integration scheme with the possibility of the substrate reuse offers a viable pathway to further reducing the processing cost associated with the fabrication of III-V solar cell devices. Furthermore, the strikingly high specific power of our devices makes them suitable for portable applications with stringent requirements on the size and weight of the photovoltaic solar cells.