TiO2: A Critical Interfacial Material for Incorporating Photosynthetic Protein Complexes and Plasmonic Nanoparticles into Biophotovoltaics

TiO2, a photosensitive semiconducting material, has been widely reported as a good photoanode material in dye-sensitized solar cells and new emerging perovskite cells. Its proper electronic band structure, surface chemistry and hydrophilic nature provide a reactive surface for interfacing with different organic and inorganic photon capturing materials in photovoltaics. Here, we review its enabling role in incorporating two special materials toward biophotovoltaics, including photosynthetic protein complexes extracted from plants and plasmonic nanoparticles (e.g., gold or silver nanoparticles), which interplay to enhance the absorption and utilization of sun light. We will first give a brief introduction to the TiO2 photoanode, including preparation, optical and electrochemical properties, and then summarize our recent research and other related literature on incorporating photosynthetic light harvest complexes and plasmonic nanoparticles onto anatase TiO2 photoanodes as a means to tap into the charge separation, electron and energy transfer, and photovoltaic enhancements in the bio-photovoltaics.