Institute of Fundamental Technological Research

The synthesis of ball-type zinc and gallium phthalocyanines (complexes 2 and 3) and their covalent linkage to glutathione
(GSH) and amine functionalized quantum dots (QDs) are reported in this work. Furthermore, their photophysical, photoinduced
resonance energy transfer and optical limiting response were investigated. We observed a decrease in the
fluorescence quantum yield with corresponding increase in the triplet quantum yield of the nanoconjugates in comparison
to the phthalocyanine complexes alone. The reverse saturable absorption was found to be dependent on excited state
absorption and the observed limiting threshold ranged from 0.32 to 1.43 J/cm2. Enhanced triplet parameters and
nonlinear optical performance was found when the complexes were covalently linked to semiconductor quantum dots
compared to carbon based graphene quantum dots.