Near-infrared-to-visible photon upconversion enabled by conjugated porphyrinic sensitizers under low-power noncoherent illumination

Jean-Hubert Olivier, Yusong Bai, Hyounsoo Uh, Hyejin Yoo, Michael J. Therien, Felix N. Castellano

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

We report four supermolecular chromophores based on (porphinato)zinc(II) (PZn) and (polypyridyl)metal units bridged via ethyne connectivity (Pyr1RuPZn2, Pyr1RuPZnRuPyr1, Pyr1RuPZn2RuPyr1, and OsPZn2Os) that fulfill critical sensitizer requirements for NIR-to-vis triplet-triplet annihilation upconversion (TTA-UC) photochemistry. These NIR sensitizers feature: (i) broad, high oscillator strength NIR absorptivity (700 nm < λmax(NIR) < 770 nm; 6 × 104 M-1 cm-1 < extinction coefficient (λmax(NIR)) < 1.6 × 105 M-1 cm-1; 820 cm-1 < fwhm < 1700 cm-1); (ii) substantial intersystem crossing quantum yields; (iii) long, microsecond time scale T1 state lifetimes; and (iv) triplet states that are energetically poised for exergonic energy transfer to the molecular annihilator (rubrene). Using low-power noncoherent illumination at power densities (1-10 mW cm-2) similar to that of terrestrial solar photon illumination conditions, we demonstrate that Pyr1RuPZn2, Pyr1RuPZn2RuPyr1, and Pyr1RuPZnRuPyr1 sensitizers can be used in combination with the rubrene acceptor/annihilator to achieve TTA-UC: these studies represent the first examples whereby a low-power noncoherent NIR light source drives NIR-to-visible upconverted fluorescence centered in a spectral window within the bandgap of amorphous silicon.

Original languageEnglish (US)
Pages (from-to)5642-5649
Number of pages8
JournalJournal of Physical Chemistry A
Volume119
Issue number22
DOIs
StatePublished - Jun 4 2015
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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