A New Way to Predict the Efficiency of Optical Limiters without Providing an Experiment: Processing of TDDFT Calculations for the Case of Pure Two-Photon Absorption

Laser-power-limiting devices play a predominant role in photonics because of their potential for protecting human eyes and optical devices that are sensitive to intense laser beams. This paper describes a new methodology for predicting the efficiency of optical limiting based on electric-field-induced changes in absorption spectra calculated with the TDDFT quantum-chemical method. Analytical equations are derived to evaluate the optical thresholds and speed of switching on, the dynamic range, and the degree of nonlinear attenuation of the radiation fluxes for the case of two-photon absorption. Thus, the researcher does not need to conduct costly experiments to evaluate the suitability of nonlinear absorbers for the creation of optical limiters. The possibility of developing a forecasting model is demonstrated by an example of a series of stable slipped-cofacial phthalocyanine J-type dimers, which were synthesized and investigated previously.

Synthesis, characterization, photophysics, and photochemistry of peripherally substituted tetrakis(quinolinylethylenephenoxy)-substituted zinc(ii) phthalocyanines

Quinoline substituted zinc phthalocyanine derivatives were synthesized and characterized, and their photophysical and photochemical properties were investigated.

Helical Self-Assembly of Optically Active Glycoconjugated Phthalocyanine J-Aggregates

Four galactoconjugated zinc(II) phthalocyanines (Pcs) have been prepared and fully characterized. The carbohydrate-containing phthalonitrile precursors of the Pcs were synthesized through a copper-catalysed azide-alkyne cycloaddition (CuAAC). The Pcs show a remarkable aggregation behaviour in solution, depending on the nature of the solvent, the temperature and the substitution position on the phthalocyanine. Solvent-dependent CD-spectroscopy experiments show that these Pcs aggregate as chiral helices in solution. Crystal structure data of a phthalocyanine bearing two carbohydrate units substantiate the properties shown by CD spectroscopy. Furthermore, the 1,2,3-triazole moieties of the Pcs play a decisive role in the formation of supramolecular aggregates. The glycoconjugated zinc(II) phthalocyanines described here show molar extinction coefficients ϵ_max >10⁵  M^-1  cm^-1 and absorption maxima λ_max >680 nm, which make them attractive photosensitizers for Photodynamic Therapy (PDT).

Aggregation of slipped-cofacial phthalocyanine J-type dimers: Spectroscopic and AFM study

Direct metallation of 2-hydroxyphthalocyanine J-type slipped-cofacial dimeric ligand by Mg, Zn, Cu, Ni and Co salts has been carried out to obtain corresponding metal complexes selectively without any noticeable dissociation or polymerization of the starting ligand. Integrated analysis of aggregation properties in the synthesized series has been conducted with the involvement of AFM microscopy, UV/Vis spectroscopy and theoretical assessment. As a result, a nonlinear relationship between absorption and concentration was found, with aggregation beginning to appear at concentrations above 3.3 × 10^-5 mol L^-1 with predominant formation of trimers from the dimeric molecules in THF solutions.

Air–water interfacial assembly of all-aromatic-substituted double-decker phthalocyanine forms aligned nanoparticles

In this manuscript, unexpected supramolecular assembly of [Formula: see text]-conjugated molecules containing complex aromatic substituents was investigated. The air–water interfacial assembly of double-decker phthalocyanines containing sixteen phenol substituents (Ce(Pc2)[Formula: see text] and Y(Pc2)[Formula: see text] form aligned nanoparticles. Depending on the different surface pressure, the Ce(Pc2)[Formula: see text] self-assembled nanostructures can be regulated thoroughly. Although Ce(Pc2)[Formula: see text] and Y(Pc2)[Formula: see text] have only aromatic substituent groups, no H- or J-aggregation of [Formula: see text]-conjugated systems can be detected from the UV-vis spectra of the assemblies of these double-decker phthalocyanines. When the nanostructures of these assemblies were changed greatly, no corresponding changes of UV-vis spectra and FT-IR spectra could be detected. These unusual results can be understood from the balance between the hydrophilicity of aromatic substituents and the ether linkages of double-decker phthalocyanines and the surface pressure, and open new. approaches for supramolecular assembly of complex [Formula: see text]-conjugated systems.

Monohydroxyphthalocyanines as potential precursors to create nanoscale optical materials

This work summarizes the achievements in the use of monohydroxyphthalocyanines for the preparation of stable J- and H-type dimers with covalent and non-covalent bonding of the macrocycles. A modified approach for the monohydroxyphthalocyanines preparation is given. Target compounds have a tendency to nanoaggregation with distinguishing optical properties which are useful for developing the next generation of optical materials.

Threshold concentration in the nonlinear absorbance law

Deviation from the Beer–Lambert law at high concentrations was described in terms of the nonlinear absorbance on the basis of a new empirical equation, which includes the threshold concentration as a breakpoint on the continuous function ‘absorption coefficient vs. concentration’.