title: A triplet-triplet annihilation based up-conversion process investigated in homogeneous solutions and oil-in-water microemulsions of a surfactant.
abstract: The triplet-triplet annihilation based up-conversion process, involving a platinum octaethyl-porphyrin (PtOEP) as a sensitizer and tetraphenyl-pyrene (TPPy) as an emitter, has been investigated in homogeneous solutions of toluene, bromobenzene and anisole, and oil-in-water microemulsions of the TX-100 surfactant, where toluene constitutes the non-polar phase. In homogeneous solutions, the highest up-conversion quantum yield (of the order of 20%) has been achieved in toluene, being the solvent that has the lowest viscosity among those explored. The up-conversion emission from the PtOEP-TPPy pair has been then investigated in a toluene based oil-in-water microemulsion at three different concentrations of the solutes, showing quantum yields up to the order of 1%, under the same irradiation conditions, but different deoxygenating procedures. The results herein reported might represent a good starting point for a future investigation in microheterogeneous systems. An optimization of the microemulsion composition, in terms of surfactant, co-surfactant and toluene concentrations, could allow us to increase the sensitizer and emitter concentrations and set up the best operative conditions to obtain even higher up-conversion efficiencies.
authors.affiliation: Dipartimento di Chimica, Università di Perugia, 06123 Perugia, Italy. fausto.ortica@unipg.it.
authors.forename: Marta
authors.initials: M
authors.lastname: Penconi
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Gentili
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Massaro
authors.forename: Fausto
authors.initials: F
authors.lastname: Elisei
authors.forename: Fausto
authors.initials: F
authors.lastname: Ortica