Photoelectrochemical cells (PECs) that mimic photosynthesis belong to the group of direct systems for converting sunlight to stored chemical energy. Common to those is the potential to become more efficient and cost effective because, unlike indirect ones, they do not involve unnecessary steps such as the sunlight to electricity conversion. Despite their greater potential, there is yet no direct conversion device that works on any technological scale. Indeed, there seems to be a large barrier linked to a poor PEC efficiency in absorbing sunlight and driving the catalysis for water oxidation (WO) and selective CO2 reduction (CO2R) to carbon-based compounds to store chemical energy. In addition, most PEC designs incorporate non-abundant or highly toxic elements precluding their future use at a larger scale. In LICROX we will implement a new PEC type incorporating three complementary light absorbing elements driving WO and CO2R. The latter consists of a tandem assembly that combines Cu nanocatalysts with molecular catalysts made of only abundant elements. The best-in-class transition metal oxides for the photo -anode and -cathode semiconductors will be used in the PEC to validate several light trapping mechanisms which have been proven to be very effective in boosting the light harvesting efficiency in thin film solar cells. To accelerate the endeavor of converting the triple junction PEC proposed into a working technology for transforming light and CO2 into compounds capable of storing chemical energy, LICROX brings together an interdisciplinary team of scientists with a comprehensive expertise in materials chemistry, semiconductor physics, electrochemistry, and photonics from EPFL, TUM, ICIQ and ICFO. Designing a strategy by DBT to overcome societal resistance, LICROX will set the route for a new scalable renewable energy technology to be initially pushed towards an industrial implementation and commercialization by AVA, HST and a newly developed spin-off from ICFO.