The effects of central metals and peripheral substituents on the photophysical properties and optical limiting performance of phthalocyanines with axial chloride ligand

A series of peripherally substituted phthalocyanines (Pcs) with different central metals (Al, Ga and In) and axial chloride ligand were synthesized and their photophysical and optical limiting properties were investigated. The Q band absorption of the Pc shifts to longer wavelength with the central metals changing from Al to In, and the fluorescence quantum yields of S1 emission decrease remarkably from Al to In. Transient absorption spectra of the Pcs in THF were measured in determination of the photophysical parameters. The optical limiting properties were investigated by a nanosecond pulse laser at 532 nm. All of these compounds exhibit good optical limiting performance, and the optical limiting behaviors of solid solution in glass obtained by sol–gel technique are much better than that of liquid solution. Several factors which affect the optical limiting performance of the Pcs with different central metals and substituents are discussed.