Photoelectrochemical cells (PECs) that mimic photosynthesis are direct systems for converting sunlight to stored chemical energy and don’t involve unnecessary steps, such as converting sunlight to electricity. Despite their potential, current PECs are very inefficient in absorbing sunlight and mostly incorporate non-abundant or highly toxic elements. To address this problem, the EU-funded LICROX project aims to implement a new PEC that incorporates three complementary light-absorbing elements driving water oxidation and CO2 reduction. The latter consists of a tandem assembly that combines copper nanocatalysts with molecular catalysts made of only abundant elements. The best-in-class compounds will be used for validating several light-trapping mechanisms to enhance PEC's light-harvesting efficiency. The project will pave the way for a new scalable renewable energy technology that efficiently converts sunlight to stored chemical energy.