One- and two-photon singlet oxygen generation with new fluorene-based photosensitizers

Stephen J. Andrasik, Kevin D. Belfield, Mykhailo V. Bondar, Florencio E. Hernandez, Alma R. Morales, Olga V. Przhonska, Sheng Yao

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


The spectral properties of new fluorene-based photosensitizes for efficient singlet oxygen production are investigated at room temperature and 77 K. Two-photon absorption (2PA) cross-sections of the fluorene derivatives are measured by the open aperture Z-scan method. The quantum yields of singlet oxygen generation under one- and two-photon excitation (ΦΔ and 2PAΦΔ, respectively), are determined by the direct measurement of singlet oxygen luminescence at ≈1270 nm. The values of ΦΔ are independent of excitation wavelength, ranging from 0.6-0.9. The singlet oxygen quantum yields under two-photon excitation are 2PAΦΔ≈1/2ΦΔ, indicating that the two processes exhibit the same mechanism of singlet oxygen production, independent of the mechanism of photon absorption.

Original languageEnglish (US)
Pages (from-to)399-404
Number of pages6
Issue number3
StatePublished - Feb 19 2007
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Physical and Theoretical Chemistry


  • Luminescence
  • Photochemistry
  • Photosensitizer
  • Singlet oxygen
  • Two-photon absorption


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