Supramolecular Crowding Can Avoid Oxygen Quenching of Photon Upconversion in Water

Hironori Kouno, Yoichi Sasaki, Nobuhiro Yanai, Nobuo Kimizuka

    Research output: Contribution to journalArticlepeer-review

    23 Citations (Scopus)


    A common challenge in chemistry that deals with photoexcited states is to avoid oxygen quenching. This is crucial for hot research fields such as photon upconversion (UC), in which oxygen-sensitive triplet excited states play pivotal roles. However, methods to avoid oxygen quenching in aqueous media are far more limited despite eagerly anticipated catalytic and biological applications. This work introduces a simple strategy to achieve air-stable triplet–triplet annihilation (TTA)-based UC in water, namely, supramolecular crowding. Amphiphilic cationic acceptor molecules and anions with long alkyl chains co-assemble in water in which hydrophobic donor molecules are molecularly dispersed. Despite the common notion that oxygen molecules diffuse readily across hydrophobic domains in water, more than 80 % of the TTA-UC emission of the obtained hydrophobic co-assemblies is maintained in air-saturated water. This work demonstrates the new promising potential of supramolecular chemistry for photophysical and photochemical functions with oxygen-sensitive species.

    Original languageEnglish
    Pages (from-to)6124-6130
    Number of pages7
    JournalChemistry - A European Journal
    Issue number24
    Publication statusPublished - Apr 26 2019

    All Science Journal Classification (ASJC) codes

    • Catalysis
    • Chemistry(all)
    • Organic Chemistry


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