Solar photovoltaics (PV) is a leading candidate for the renewable, carbon-free electricity generation with both the scalability and technological maturity to meet the ever-growing global demand for energy. While PV module costs continue to decline rapidly, further system-level cost reductions will require lightweight, sustainable, and flexible module designs that are still inaccessible with today’s mainstream technologies. SMARTCELL proposes an innovative PV technology based on zinc phosphide (Zn3P2), an earth-abundant, low-cost, direct bandgap semiconductor for development of novel ultra-thin solar cells. SMARTCELL will implement novel technological solutions based on advanced nanofabrication methods for synthesis of high crystal quality zinc phosphide, which together with design and optimization of the device interfaces and the cell architecture will lead to achievement of a challenging increase in the device efficiency of up to 15 % at the cell level. These efficiencies will allow initiating the transfer of zinc phosphide based solar cells to pre-industrial stages and give SMARTCELL the opportunity to demonstrate scalable, cost-effective, and environmentally-friendly ultrathin-film PV technology. The working principle of SMARTCELL is based on a holistic interplay between first-principle calculations, synthesis conditions, and atomic-resolution structural and electronic characterization techniques, which will allow cutting-edge engineering of absorber properties, as well as the design of the solar cell architectures. Moreover, an integrated, flexible methodology will keep this target breakthrough in sight. Finally, SMARTCELL has the potential to make a key science-based contribution to energy security, as well as improved societal perception of green energy production.