Preorganized Chromophores Facilitate Triplet Energy Migration, Annihilation and Upconverted Singlet Energy Collection

Prasenjit Mahato, Nobuhiro Yanai, Melinda Sindoro, Steve Granick, Nobuo Kimizuka

    Research output: Contribution to journalArticlepeer-review

    28 Citations (Scopus)

    Abstract

    Photon upconversion (UC) based on triplet-triplet annihilation (TTA) has the potential to enhance significantly photovoltaic and photocatalytic efficiencies by harnessing sub-bandgap photons, but the progress of this field is held back by the chemistry problem of how to preorganize multiple chromophores for efficient UC under weak solar irradiance. Recently, the first maximization of UC quantum yield at solar irradiance was achieved using fast triplet energy migration (TEM) in metal-organic frameworks (MOFs) with ordered acceptor arrays, but at the same time, a trade-off between fast TEM and high fluorescence efficiency was also found. Here, we provide a solution for this trade-off issue by developing a new strategy, triplet energy migration, annihilation and upconverted singlet energy collection (TEM-UPCON). The porous structure of acceptor-based MOF crystals allows triplet donor molecules to be accommodated without aggregation. The surface of donor-doped MOF nanocrystals is modified with highly fluorescent energy collectors through coordination bond formation. Thanks to the higher fluorescence quantum yield of surface-bound collectors than parent MOFs, the implementation of the energy collector greatly improves the total UC quantum yield. The UC quantum yield maximization behavior at ultralow excitation intensity was retained because the TTA events take place only in the MOF acceptors. The TEM-UPCON concept may be generalized to collectors with various functions and would lead to quantitative harvesting of upconverted energy, which is difficult to achieve in common molecular diffusion-based systems.

    Original languageEnglish
    Pages (from-to)6541-6549
    Number of pages9
    JournalJournal of the American Chemical Society
    Volume138
    Issue number20
    DOIs
    Publication statusPublished - May 25 2016

    All Science Journal Classification (ASJC) codes

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

    Fingerprint

    Dive into the research topics of 'Preorganized Chromophores Facilitate Triplet Energy Migration, Annihilation and Upconverted Singlet Energy Collection'. Together they form a unique fingerprint.

    Cite this