Ultrathin Langmuir–Schaefer Films of Slipped-Cofacial J-type Phthalocyanine Dimer: Supramolecular Organization, UV/Vis/NIR Study and Nonlinear Absorbance of Femtosecond Laser Radiation

Based on a comprehensive theoretical and experimental approach, a low-defect thin film of stable dimeric phthalocyanine zinc complex (bis[2-hydroxy-9(10),16(17), 23(24)-tri-tert-butylphthalocyaninel zinc - J-[(PcZn)-Pc-OH-Zn-t](2)) was prepared. It is shown that the dye forms stable amorphous edge-on monolayers at the air/water interface with an insignificant content of cylindrical 3D aggregates. These floating layers keep their structure when transferred by the Langmuir-Schaefer method onto a solid substrate, demonstrating a tendency towards ordered H-aggregation with preserving their linear molecular properties. Mixed two- and three-photon absorption of femtosecond laser pulses (280 fs) was firstly detected on this sample, as well as the ability of a material to the nonlinear attenuation of the intense irradiation, which is important for optical limiting.