Langmuir-Schaefer films based on cyclotriphosphazene-substituted phthalocyanines: Supramolecular organization, UV/Vis study, and laser-induced nonlinear absorption

[Display omitted] •Cyclotriphosphazene-substituted phthalocyanines can form low-defect films.•The Langmuir-Schaefer method is suitable for creating optical limiters.•An increase in the number of layers leads to more efficient nonlinear absorption. Low-defective thin films of 2-hydroxy-9(10),16(17),23(24)-tri-tert-butylphthalocyanine (1), as well as its cyclotriphosphazene-substituted derivatives, monomer (2) and clamshell-like dimer (3), have been obtained and extensively studied. It is shown that these dyes produce stable floating layers with a certain number of three-dimensional aggregates at the air/water interface. The floating layers retain their structure when transferred to a glass substrate by the Langmuir-Schaefer method, demonstrating the H-aggregation of the dyes. In contrast to the initial monohydroxyphthalocyanine 1, thin films of its derivatives, cyclotriphosphazene-substituted monomer 2 and dimer 3, show a slight increase in absorption when the number of deposited layers exceeds 100. It is shown that thin films of the studied dyes 1–3 can be used in the technology of optical limitation of laser radiation, demonstrating a good cutting efficiency of dangerous nanosecond pulses.