Title
All-or-None Switching of Photon Upconversion in Self-Assembled Organogel Systems
Author
Pengfei Duan, Deepak Asthana, Takuya Nakashima, Tsuyoshi Kawai, Nobuhiro Yanai, Nobuo Kimizuka
Year
2016
Journal
Faraday Discussions
Abstract
Aggregation-induced photon upconversion (iPUC) based on triplet-triplet annihilation (TTA) process is successfully developed by controlled self-assembly of donor-acceptor pairs in organogel nanoassemblies. Alghouth segrigation of donor from acceptor assemblies has been an outstanding problem in TTA-based UC and iPUC, we resolved this issue by modifying both of triplet donor and aggregation induced emission (AIE)-type acceptor with glutamate-based selfassembling moieties. These donor and acceptor co-assemble to form organogels without segretation. Interestingly, these donor-acceptor binary gels show upconversion at room temperature but upconversion phenomena were lost upon dissolution of gels by heating. The oberved changes in TTA-UC emission was thermally reversible, reflecting controlled assembly/disassembly of the binary molecular systems. The observed on/off ratio of UC emission was much higher than that of aggregation-induced fluorescence of acceptor, which highlights the important role of iPUC, i.e., multi-exciton TTA for photoluminescence switching. This work bridges the iPUC and supramolecular chemistry, which provides a new strategy for designing stimuli-responsive upconversion systems
Instrument
J-810
Keywords
Circular dichroism, Circularly polarized luminescence, Stereochemistry, Materials