Enabling High Energy Photochemistry through Photon Upconversion

Solar radiation constitutes more than 99% of all renewable energy available near the Earth’s surface.

Efficient use in solar cells is hampered by the so-called spectrum losses, limiting the theoretical efficiency to approximately 30%.

Similar limitations apply to any other solar driven photochemical process, including natural photosynthesis and solar fuels reactions.

To go beyond this limit, we propose to construct benchmarking molecular materials capable of supporting triplet-triplet annihilation upconversion (TTA-UC) with high efficiencies.

TTA-UC systems with high quantum yields have been presented operating in the visible region but the corresponding systems upconverting into the UV-region is much less efficient.

With this project we want to develop and investigate TTA-UC systems capable of upconverting the blue/green part of the visible solar spectrum into the UV-region and thereby enable solar-driven high energy photochemistry with far reaching applications.

To this end, interplay between chemical synthesis and advanced spectroscopic methods will be used: (1) to develop novel systems and interrogate the loss mechanisms that limit the TTA-UC yield, (2) to develop quantum dot-based sensitizers, (3) to demonstrate proof-of-principle photochemical energy-storage reactions powered by upconverted sunlight.

These materials will pave the way for new technologies, including photochemical water splitting on wide band-gap semiconductors, such as TiO2.