Estimation of Fluorescence Lifetimes of Zinc Phthalocyanine in various Organic Solvents – A Semi-Empirical Approach

Abstract

The effect of solvents on the ground state electronic absorption spectra and fluorescence properties of zinc phthalocyanine is presented. Q-band positions vary between 668 nm (in tetrahydrofuran) and 677 nm (in 1-chloronaphthalene), and is found to be solvent refractive index-dependent. The fluorescence quantum yields, fluorescence lifetimes and SternVolmers quenching constant for fluorescence quenching by benzoquinone are all solvent viscosity-dependent, with the most viscous solvent exhibiting the highest values. The SternVolmers quenching constant, together with the calculated bimolecular quenching constant were used in the determination of fluorescence lifetime. This work presents a semi-empirical approach for the determination of fluorescence lifetime of a fluorophore, which is its main objective. The fluorescence lifetime of zinc phthalocyanine ranges between 2.89 nm in tetrahydrofuran and 5.06 nm in 1-chloronaphthalene.