Tuning the concentration of dye loaded polymer films for maximum photosensitization efficiency: Phloxine B in poly(2-hydroxyethyl methacrylate)
Fluorescence and singlet molecular oxygen (1O2) quantum yields for phloxine B loaded poly(2-hydroxyethyl methacrylate) thin films are determined at dye concentrations from 0.015 to 22 wt%. Fluorescence self-quenching and the fall off of the 1O2 quantum yield observed above 0.1 wt% are attributed to...
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| Autores principales: | , , |
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| Formato: | JOUR |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_1474905X_v15_n1_p80_Litman |
| Aporte de: |
| Sumario: | Fluorescence and singlet molecular oxygen (1O2) quantum yields for phloxine B loaded poly(2-hydroxyethyl methacrylate) thin films are determined at dye concentrations from 0.015 to 22 wt%. Fluorescence self-quenching and the fall off of the 1O2 quantum yield observed above 0.1 wt% are attributed to very weakly interacting close-lying dye molecules acting as energy traps arising from molecular confinement. The maximum singlet oxygen generation efficiency (quantum yield × absorption factor) lies at concentrations around 2 wt%, where fluorescence self quenching amounts to more than 80%. Data are fitted quantitatively by using a quenching radius model involving energy migration and trapping with rQ = 1.2 nm. The present results constitute a proof of concept for the rational design of heterogeneous photosensitizers in general and, particularly, for applications in which the antimicrobial activity of singlet oxygen is central. © 2016 The Royal Society of Chemistry and Owner Societies. |
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