Photon energy upconversion in porphyrins: one-photon hot-band absorption versus two-photon absorption

نویسندگان

  • M. Drobizhev
  • A. Karotki
  • M. Kruk
  • A. Krivokapic
  • H. L. Anderson
  • A. Rebane
چکیده

We study the porphyrin S1 ! S0 fluorescence and the photosensitized singlet oxygen Dg ! Rg phosphorescence, both originating from absorption of photons with energy less than the porphyrin S0 ! S1 transition energy. By measuring the excitation intensity dependence of fluorescence at lowered sample temperatures, we are able to discriminate between two parallel processes of one-photon hot-band absorption (HBA) and simultaneous two-photon absorption (TPA). When the HBA and TPA contributions are comparable in magnitude, we use this new method to determine absolute TPA cross-section. We also demonstrate for the first time a singlet oxygen photosensitization via

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تاریخ انتشار 2003