The future of energy supply depends on innovative breakthroughs regarding the design of efficient systems for the conversion and storage of solar energy. The production of H2 through direct light-driven water-splitting in a Photo-Electro-Chemical (PEC) cell, appears as a promising solution. However such cells need to respond to three main characteristics: sustainability, cost-effectiveness and stability. Fulfilling these requirements raise important scientific questions regarding the elaboration and combination of the best materials able to harvest light and catalyse H2 and O2 evolution.The objective of this project is to design an operating photocathode based on Earth abundant elements for PEC H2 production, answering therefore the sustainability and cost issues. The novelty relies on the approach gathering organic and hybrid photovoltaics with artificial photosynthesis to design new materials and architectures: I will combine and immobilize molecular photosensitizers with bioinspired catalysts on an electrode thanks to electronic junctions. This will allow (i) optimizing light-driven charge separation, (ii) driving electrons from the electrode to the catalyst, (iii) and limiting charge recombination processes.The project is divided into four tasks. The two first tasks are focused on the elaboration of new photoelectrode architectures: In task 1, I propose to engineer a H2-evolving electrode thanks to donor-acceptor dyes immobilized on p-type semi-conductors. In task 2, I propose to implement organic photovoltaics materials in a H2-evolving electrode. The third task focuses on the elaboration of new catalysts, incorporating redox-active (non-innocent) ligands in order to systematically bias electron transfer towards the catalyst. These new catalysts will be implemented on the new photoelectrode architectures.The last task focuses on the ultimate assembly of a PEC cell and on the performance assessments at all steps of the project (photocathodes and full cell).