Time-resolved luminescence and singlet oxygen formation under illumination of hypericin in acetone |
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| Authors: | P Gbur R De?dic D Jancura P Mi?kovský J Hála |
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| Institution: | 1. Department of Biophysics, P.J. ?afárik University, Jesenná 5, 041 54 Ko?ice, Slovakia;2. Faculty of Mathematics and Physics, Department of Chemical Physics and Optics, Charles University, Ke Karlovu 3, 121 16 Praha 2, Czech Republic;3. International Laser Center, Ilkovi?ova 3, 812 19 Bratislava, Slovakia;1. Departamento de Física de Materiales, Universidad Autónoma de Madrid, 28049 Madrid, Spain;2. Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, 28049 Madrid, Spain;3. Departamento de Física de Materiales, Universidad Autónoma de Madrid, 28049 Madrid, Spain |
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| Abstract: | We present time- and spectral-resolved phosphorescence study of hypericin as well as evolution of singlet oxygen formation and elimination under the illumination of hypericin in acetone solution. The obtained time-resolved hypericin phosphorescence can be satisfactorily fitted by using a two-exponential decay curve. The value of shorter component is about 0.29 μs and is independent of the hypericin concentration in the studied range (2–200 μM). The rise time of singlet oxygen production matches this value perfectly. It confirms that singlet oxygen formation represents the significant channel of hypericin triplet state deactivation under aerobic conditions at room temperature. The total phosphorescence intensity of hypericin is linearly proportional to the hypericin concentration within the studied concentration range, but the singlet oxygen phosphorescence intensity exhibits saturation behavior. This observation is a result of at least two effects: quenching of singlet oxygen by hypericin, as well as quenching of singlet oxygen by singlet oxygen. |
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