title: Sensing and imaging of oxygen with parts per billion limits of detection and based on the quenching of the delayed fluorescence of (13)C70 fullerene in polymer hosts.
abstract: We report on a new method for sensing trace oxygen in the gas phase. It is based on the extreme efficiency of the quenching of the thermally activated delayed fluorescence of isotopically enriched carbon-13 fullerene C(70) ((13)C(70)). This fullerene was dissolved in polymer matrixes of varying oxygen permeability, viz., polystyrene (PS), ethyl cellulose (EC) and an organically modified silica gel ("ormosil"; OS). The sensor films (5-10 μm thick), on photoexcitation at 470 nm, display a strong delayed photoluminescence with peaks between 670 and 700 nm. Its quenching by molecular oxygen was studied at 25 and 60 °C and at concentrations from zero up to 150 ppmv of oxygen in nitrogen. The rapid lifetime determination (RLD) method was applied to determine oxygen-dependent lifetimes and for fluorescence lifetime imaging of oxygen. The lower limits of detection (at 1% quenching) vary with the polymer used (EC ∼250 ppbv, OS ∼320 ppbv, PS ∼530 ppbv at 25 °C) and with temperature. The oxygen sensors reported here are the most sensitive ones described so far.
authors: Sven
authors: S
authors: Kochmann
authors: Carlos
authors: C
authors: Baleizão
authors: Mário N
authors: MN
authors: Berberan-Santos
authors: Otto S
authors: OS
authors: Wolfbeis
mesh_terms: D002247:Carbon Isotopes; D037741:Fullerenes / Q000737:chemistry*; D057230:Limit of Detection; D010100:Oxygen / Q000032:analysis*; D011108:Polymers / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D002247:Carbon Isotopes; D037741:Fullerenes; D011108:Polymers; C069836:fullerene C70; D010100:Oxygen