Radically Reimagining III-V Compound Semiconductor Photovoltaics: Epitaxy-Free Approach to Scalable Synthesis of Flexible Low-Cost Thin-Film Solar Cells

For III-V compound semiconductor solar cells to achieve scalability for very large-scale space and terrestrial photovoltaics, we need to radically reimagine how they are fabricated. We outline an approach for scalable synthesis of GaAs and InP thin film solar cells that bypasses epitaxial growth and eliminates or minimizes vacuum processing. Starting with thin film absorbers that are formed by mechanical exfoliation from GaAs and InP ingots bulk ingots, we demonstrate that high efficiency cells are possible using methods adopted from silicon and perovskite thin film photovoltaics, such as use of diffused junctions formed at ambient pressures, and solution processing of ohmic contacts and passivation layers using earth-abundant materials. We demonstrate diffused junction GaAs solar cells with 1-Sun AM1.5G efficiencies as high as 21.5%. We also performed a technoeconomic analysis indicating a pathway for III-V photovoltaics to achieve LCOE parity with future silicon photovoltaics, with a lower capital cost/Watt for manufacturing.