Photochemical upconversion is suppressed by high concentrations of molecular sensitizers

Elham M. Gholizadeh, Laszlo Frazer, Rowan W. MacQueen, Joseph K. Gallaher, Timothy W. Schmidt

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9 Citations (Scopus)


Photochemical upconversion uses sensitized triplet-triplet annihilation in bimolecular compositions to convert lower energy photons to higher energy photons. For high efficiency under low illumination, usually a high sensitizer concentration is desirable. However, here we show that the upconversion sensitizer can reduce the emitter triplet lifetime by dynamic quenching, with rate constants on the order 106 M-1 s-1, leading to diminishing returns beyond a certain concentration. These results serve as a warning to designers of photochemical upconvertors that higher concentrations of sensitizers are not necessarily beneficial to upconversion performance.

Original languageEnglish
Pages (from-to)19500-19506
Number of pages7
JournalPhysical Chemistry Chemical Physics
Issue number29
Publication statusPublished - 1 Jan 2018

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