Nonlinear optical behavior of alkyne terminated phthalocyanines in solution and when embedded in polysulfone as thin films: Effects of aggregation

•Synthesis of zinc- and metal-free alkyne tetra substituted phthalocyanines is reported.•The metal free derivative gives improved nonlinear optical behavior when aggregated.•Improved nonlinear optical behavior is observed in thin films compared to solution.

We report here for the first time, on the comparative studies of the photophysical and optical limiting behavior of our two novel phthalocyanines namely 2(3), 9(10), 16(17), 23(24)-tetrakis-(4-(5-methylhex-1-yn-3-yloxy)) phthalocyanines 2, and 2(3), 9(10), 16(17), 23(24)-tetrakis-(4-(5-methylhex-1-yn-3-yloxy)) phthalocyaninato zinc (II) (3) in solution and thin films. Nonlinear optical (NLO) properties of the samples in solution and contained in polysulfone (PSU) thin films were evaluated using Z-scan technique at 532 nm and 10 ns pulsed duration. Effects of aggregation and disaggregation on the NLO performance of metal-free phthalocyanine are reported in detail. Our findings showed that the prepared Pcs show larger nonlinear absorption coefficient and lower limiting thresholds when embedded in polysulfone films compared to in solutions. The values of nonlinear susceptibility and hyperpolarizability recorded for 3-PSU in this work are respectively, ∼2.09 × 10−8 esu and ∼1.02 × 10−26 esu. These values are among the largest values reported for phthalocyanines and other macrocycles doped on polymer matrices.

Graphical abstractMetal free and Zn complexes of 2(3), 9(10), 16(17), 23(24)-tetrakis-(4-(5-methylhex-1-yn-3-yloxy)) phthalocyanines show improved nonlinear optical properties when embedded in polysulfone thin films and when aggregated in solution for the metal free derivative.Figure optionsDownload full-size imageDownload high-quality image (52 K)Download as PowerPoint slide