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Photocatalytic Water-Splitting Enhancement by Sub-Bandgap Photon Harvesting

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Monguzzi Angelo, Oertel Amadeus, Braga Daniele, Riedinger Andreas, Kim David K., Knüsel Philippe N., Bianchi Alberto, Mauri Michele, Simonutti Roberto, Norris David J., Meinardi Francesco,
Project Electronic Impurity Doping of Semiconductor Nanocrystals
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Original article (peer-reviewed)

Journal ACS Applied Materials & Interfaces
Volume (Issue) 9(46)
Page(s) 40180 - 40186
Title of proceedings ACS Applied Materials & Interfaces
DOI 10.1021/acsami.7b10829


Upconversion is a photon-management process especially suited to water-splitting cells that exploit wide-bandgap photocatalysts. Currently, such catalysts cannot utilize 95% of the available solar photons. We demonstrate here that the energy-conversion yield for a standard photocatalytic water-splitting device can be enhanced under solar irradiance by using a low-power upconversion system that recovers part of the unutilized incident sub-bandgap photons. The upconverter is based on a sensitized triplet−triplet annihilation mechanism (sTTA-UC) obtained in a dye-doped elastomer and boosted by a fluorescent nanocrystal/polymer composite that allows for broadband light harvesting. The complementary and tailored optical properties of these materials enable efficient upconversion at subsolar irradiance, allowing the realization of the first prototype water-splitting cell assisted by solid-state upconversion. In our proof-of concept device the increase of the performance is 3.5%, which grows to 6.3% if concentrated sunlight (10 sun) is used. Our experiments show how the sTTA-UC materials can be successfully implemented in technologically relevant devices while matching the strict requirements of clean-energy production.