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Luminescence quenching of Ru(II) complexes in polydimethylsiloxane sensors for oxygen

1999; Elsevier BV; Volume: 120; Issue: 1 Linguagem: Inglês

10.1016/s1010-6030(98)00418-3

1873-2666

Mariano L. Bossi, Marta E. Daraio, Pedro F. Aramendı́a,

Photochemistry and Electron Transfer Studies

The luminescence quenching of ruthenium(II)-tris(1,10-phenanthroline) and ruthenium(II)-tris(4,7-diphenyl-1,10-phenanthroline) by oxygen in films of commercial polydimethylsiloxane was studied by steady state and time-resolved methods. The decay kinetics is not monoexponential in the absence and in the presence of oxygen. It can be accurately described in all cases by the function exp(−Bt1/2), a particular case of the stretched exponential behaviour often found in solid media. The steady state and integrated time-resolved quenching efficiency coincide and show a downward curvature as a function of oxygen partial pressure. This dependence is explained by assuming a Freundlich type adsorption of oxygen in the dopants of the polymer. Both complexes render the same dependence of adsorbed oxygen on its partial pressure.