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One‐ and Two‐Photon Singlet Oxygen Generation with New Fluorene‐Based Photosensitizers
Author(s) -
Andrasik Stephen J.,
Belfield Kevin D.,
Bondar Mykhailo V.,
Hernandez Florencio E.,
Morales Alma R.,
Przhonska Olga V.,
Yao Sheng
Publication year - 2007
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200600568
Subject(s) - singlet oxygen , fluorene , photochemistry , absorption (acoustics) , chemistry , singlet state , excitation , oxygen , atomic physics , excited state , physics , optics , organic chemistry , quantum mechanics , polymer
The spectral properties of new fluorene‐based photosensitizers 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 ( Φ Δ and 2PA Φ Δ , respectively), are determined by the direct measurement of singlet oxygen luminescence at ≈1270 nm. The values of Φ Δ are independent of excitation wavelength, ranging from 0.6–0.9. The singlet oxygen quantum yields under two‐photon excitation are 2PA Φ Δ ≈ 1/2Φ Δ , indicating that the two processes exhibit the same mechanism of singlet oxygen production, independent of the mechanism of photon absorption.