Premium
Photon‐Upconverting Ionic Liquids: Effective Triplet Energy Migration in Contiguous Ionic Chromophore Arrays
Author(s) -
Hisamitsu Shota,
Yanai Nobuhiro,
Kimizuka Nobuo
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201505168
Subject(s) - chromophore , ionic liquid , photon upconversion , phosphonium , photochemistry , chemistry , ionic bonding , ion , fluorescence , organic chemistry , physics , quantum mechanics , catalysis
Inspired by the bicontinuous ionic‐network structure of ionic liquids (ILs), we developed a new family of photofunctional ILs which show efficient triplet energy migration among contiguously arrayed ionic chromophores. A novel fluorescent IL, comprising an aromatic 9,10‐diphenylanthracene 2‐sulfonate anion and an alkylated phosphonium cation, showed pronounced interactions between chromophores, as revealed by its spectral properties. Upon dissolving a triplet sensitizer, the IL demonstrated photon upconversion based on triplet–triplet annihilation (TTA‐UC). Interestingly, the TTA‐UC process in the chromophoric IL was optimized at a much lower excitation intensity compared to the previous nonionic liquid TTA‐UC system. The superior TTA‐UC in this IL system is characterized by a relatively high triplet diffusion constant (1.63×10 −6 cm 2 s −1 ) which is ascribed to the presence of ionic chromophore networks in the IL.