Organic functional Materials for solar-to-chemical energy conversion

Solar-to-chemical energy conversion, so-called artificial photosynthesis, is one of the key technologies for realizing a sustainable future through the carbon-neutral production and use of chemicals. Over the past decades, numerous efforts have been devoted to the development of efficient artificial photosynthetic devices. Conventionally, inorganic materials have been dominantly investigated for the design and fabrication of such devices. However, these inorganic materials have many inherent limitations, such as a low absorption coefficient, severe surface recombination, insufficient electrical conductivity, and poor catalytic activity. As a result, these devices generally have a solar-to-chemical conversion efficiency insufficient for practical application. To address these issues, many researchers started paying attention to organic functional materials. Although organic materials have been less explored to date mainly due to their stability concerns under harsh photoelectrochemical reaction conditions, many organic or organic/inorganic hybrid devices that outperform conventional inorganic counterparts have been reported recently. In this talk, I will present recent efforts on the fabrication of efficient and reliable solar-to-chemical energy conversion devices using organic materials as various functional components, such as light-absorbers, passivation materials, and electrocatalysts. In particular, I will present our recent results about bias-free organic photoelectrochemical devices with a solar-to-hydrogen conversion efficiency approaching 20%