The generation of renewable H₂ through an efficient photochemical route requires photoinduced electron transfer from a light harvester to an efficient electrocatalyst in water [1]. Different approaches have been faced by the scientific community for water splitting [2] ranging from inorganic semiconductors [3] as real breakthroughs to organic ones [4], much less studied. The Photoelectrochemical hydrogen production through hybrid organic/inorganic interfaces (PHOCS) project is actually devoted to such state of the art problem, based on the role of organic electronics for energy applications [5]. Here we report our latest findings on pursuing suitable candidates for full photoelectrochemical devices based on organic active layers and inorganic electrodes combinations in form of thin films. Semiconductive polymers in conjunction with fullerene-based acceptors compounds, sandwiched between properly engineered interlayers were assembled and characterized by means of electrochemical measurements, spectroscopic techniques and microscopy. Results are discussed in terms of tuning the optical band gap for charge transfer processes, the mesostructured character of inorganic transition metal oxides as scaffolds for suitable coupling with polymer at ohmic contact and surface modifications to minimize energy barriers, work function and electron collection; thus enhancing higher photocurrents. Gas chromatography measurements proved 100% faradaic efficiency and confirmed hydrogen generation by these new electrode architectures for solar water splitting.The implications of the results presented shed light into the forthcoming optimization processes pointing to the full photoelectrochemical devices as a proof of concept for hydrogen generation.  

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