Fabrication of efficient nonlinear optical absorber using Zn phthalocyanine-semiconductor quantum dots conjugates

In this paper, we report on the synthesis of Zn(II) phthalocyanine derivatives and their conjugates with core/shell and core/shell/shell semiconductor quantum dots (SQDs). Zn(II) mono amino-carboxyethylphenoxy phthalocyanine (1), Zn(II) mono 3-carboxyphenoxy-tris(pyridin-2-yloxy) phthalocyanine (2) and Zn(II) mono aminophenoxy-tris(benzothiazole) phthalocyanine (3) were synthesized. The photophysical and optical limiting properties of the phthalocyanine (Pc) complexes and their conjugates with SQDs were investigated in dimethyl sulfoxide. The optical limiting behaviour of the Pc complexes and their conjugates were measured by the open aperture Z-scan technique at laser excitation wavelength of 532 nm with 10 ns pulse. The conjugates outperformed the Pc complexes alone with the conjugates of 2-SQDs affording highest nonlinear absorption coefficient (beta(eff)) value of similar to 80 cm/GW and lowest limiting threshold (I-lim) value of similar to 0.27 J.cm(-2) as compared to other samples while complex 1 gave low beta(eff) and high I-lim values of 42.2 cm/GW and 1.39 J.cm(-2), respectively. (C) 2018 Elsevier Ltd. All rights reserved.