Photophysical studies on axially substituted indium and gallium phthalocyanines upon UV–Vis laser irradiation

A series of results from different photophysical experiments on indium and gallium phthalocyanine (Pc) compounds is reported. Gallium Pcʹs have much longer singlet and triplet excited state lifetimes in comparison with indium Pcʹs. The strong reverse saturable absorption observed at 532 nm excitation is a consequence of the increase in absorbance of Pcʹs in the triplet excited state in the optical window comprised between Q- and B-bands, as verified upon laser irradiation with ns pulses at 355 nm. Using C60 as a reference, the intersystem cross quantum yields of tBu4PcInCl and tBu4PcGaCl are 0.70 and 0.36, respectively.