| 초록 |
Triplet—triplet annihilation (TTA) enables access to high-energy photons with incoherent low-energy photons. In the TTA-based upconversion (UC) of photons, triplettriplet—energy transfer (TTET) from a sensitizer to an annihilator is the limiting process. To improve the efficiency of TTET, we have designed a TTA-UC ion pair. The ion pair comprises a divalent Os(II) complex sensitizer of 2,6-bis(1-(2-ethylhexyl)-1H-benzo[d]imidazol-2-yl)pyridine ligands and two monoanionic 9,10-di(phenylethynyl)anthracene carboxylate annihilators. The design attains short distances not only between the sensitizer and the annihilator, but also between two annihilators. This TTA-UC system produces strong UC blue emission at a wavelength of 482 nm upon photoexcitation by near-infrared light (λ = 777 nm), which corresponds to an anti-Stokes shift as large as 1.0 eV. |
