title: Recent emergence of photon upconversion based on triplet energy migration in molecular assemblies.
abstract: An emerging field of triplet energy migration-based photon upconversion (TEM-UC) is reviewed. Highly efficient photon upconversion has been realized in a wide range of chromophore assemblies, such as non-solvent liquids, ionic liquids, amorphous solids, gels, supramolecular assemblies, molecular crystals, and metal-organic frameworks (MOFs). The control over their assembly structures allows for unexpected air-stability and maximum upconversion quantum yield at weak solar irradiance that has never been achieved by the conventional molecular diffusion-based mechanism. The introduction of the "self-assembly" concept offers a new perspective in photon upconversion research and triplet exciton science, which show promise for numerous applications ranging from solar energy conversion to chemical biology.
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. yanai@mail.cstm.kyushu-u.ac.jp n-kimi@mail.cstm.kyushu-u.ac.jp and PRESTO, JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Yanai
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. yanai@mail.cstm.kyushu-u.ac.jp n-kimi@mail.cstm.kyushu-u.ac.jp.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kimizuka