Edge, Ruth

Labidi, Sana

Tanielian, Charles

Wolff, Christian

The external heavy-atom effect, which is commonly used to enhance the triplet yield of photosensitizers, is applied here to allow the determination of accurate values of the parameter SΔ that describes the efficacy with which the triplet reacts with O2 to produce O2 (1Δg) (quantum yield Δ). The study of the effect of halogenated compounds Q addition on the luminescence intensity of O2 (1Δg) at 1270 nm or on the rate of O2 consumption for three porphyrin derivatives allows to get precise values of Δ/SΔ and then of SΔ. It is concluded that (i) the probability SΔ is equal to unity for TPP, MgTTP and pheophytin a, (ii) the best balance between ease of use and results accuracy is provided by the time-resolved luminescence of O2 (1Δg) at 1270 nm technique and the determination of the parameters with equation 6 involving relative change in fluorescence yields F/FQ and in luminescence intensities of singlet oxygen LQ/L, and (iii) TPP, a readily available sensitizer, is recommended as a reference compound with Δ = 0.80 in aerated benzene 

The University of Manchester - Institutional Repository

Heavy-atom effect on time-resolved luminescence of singlet oxygen. Determination of SΔ, the probability that triplet quenching by oxygen produces O2 (1Δg).

Heavy-atom effect on time-resolved luminescence of singlet oxygen. Determination of SΔ, the probability that triplet quenching by oxygen produces O2 (1Δg).

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The University of Manchester - Institutional Repository