Semiconductors suffer from the inability to harvest photons with energy lower than their bandgap, therefore limiting their efficiency in solar energy applications. To mitigate this problem, photons of low energy can be upconverted into higher energy light at low flux through sensitized triplet-triplet annihilation, resulting in sub-bandgap sensitization of semiconductors without any chemical modification of the latter. This presentation will describe numerous examples of upconversion phenomena realized in solution and solid-state polymeric materials along with emerging classes of acceptor/annihilator chromophores. Triplet fusion processes will be shown to operate at high efficiencies with concomitant linear incident power density response, demonstrated in both theory and experiment using non-coherent photons. Finally, upconversion-based photoaction observed in water splitting photoelectrochemical cells and operational photovoltaics will be discussed.

Photochemical upconversion and its applications in solar energy capture, conversion, and storage

247th National Meeting (2014)

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