title: Highly Efficient Photon Upconversion in Self-Assembled Light-Harvesting Molecular Systems.
abstract: To meet the world's demands on the development of sunlight-powered renewable energy production, triplet-triplet annihilation-based photon upconversion (TTA-UC) has raised great expectations. However, an ideal highly efficient, low-power, and in-air TTA-UC has not been achieved. Here, we report a novel self-assembly approach to achieve this, which enabled highly efficient TTA-UC even in the presence of oxygen. A newly developed lipophilic 9,10-diphenylanthracene-based emitter molecule functionalized with multiple hydrogen-bonding moieties spontaneously coassembled with a triplet sensitizer in organic media, showing efficient triplet sensitization and subsequent triplet energy migration among the preorganized chromophores. This supramolecular light-harvesting system shows a high UC quantum yield of 30% optimized at low excitation power in deaerated conditions. Significantly, the UC emission largely remains even in an air-saturated solution, and this approach is facilely applicable to organogel and solid-film systems.
authors.affiliation: Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Ogawa
authors.affiliation: 1] Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan [2] PRESTO, JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Yanai
authors.affiliation: Dipartimento di Scienza dei Materiali, Università Milano Bicocca, via R. Cozzi 53, 20125, Milano, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Monguzzi
authors.affiliation: Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kimizuka