Toward Higher Efficiency of Low-Cost Flexible Single-Crystal-Like GaAs Thin Film Solar Cells on Metal Tapes

III-V compound semiconductors are the best photovoltaic solar cell (SC) materials for highest conversion efficiencies. However, they are expensive and lack in mechanical flexibility and manufacturing scalability. We developed a new PV platform where nearly single-crystalline III-V thin films were directly deposited on inexpensive polycrystalline metal tapes. While a promising efficiency of ~7.5% was achieved for flexible single junction SCs on this platform, the open circuit voltage of SC suffers from minority carrier recombination at grainboundary sites according to a simulation study. A bulk passivation treatment is conducted on the SC devices which resulted in more than 350mV increase for Voc.