Near-Infrared-to-Visible Photon Upconversion Sensitized by a Metal Complex with Spin-Forbidden yet Strong S0-T1 Absorption

Shogo Amemori, Yoichi Sasaki, Nobuhiro Yanai, Nobuo Kimizuka

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83 Citations (Scopus)


Near-infrared (NIR)-to-visible (vis) photon upconversion (UC) is useful for various applications; however, it remains challenging in triplet-triplet annihilation-based UC, mainly due to the energy loss during the S1-to-T1 intersystem crossing (ISC) of molecular sensitizers. In this work, we circumvent this energy loss by employing a sensitizer with direct S0-to-T1 absorption in the NIR region. A mixed solution of an osmium complex having a strong S0-T1 absorption and rubrene emitter upconverts NIR light ( = 938 nm) to visible light ( = 570 nm). Sensitizer-doped emitter nanoparticles are prepared by re-precipitation and dispersed into an oxygen-barrier polymer. The obtained composite film shows a stable NIR-to-vis UC emission based on triplet energy migration (TEM), even in air. A high UC quantum yield of 3.1% is observed for this TEM-UC system, expanding the scope of molecular sensitizers for NIR-to-vis UC.

Original languageEnglish
Pages (from-to)8702-8705
Number of pages4
JournalJournal of the American Chemical Society
Issue number28
Publication statusPublished - Jul 20 2016

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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