Minquan Tian

Organic Optical Limiter with a Strong Nonlinear Absorptive Response

Molecules with weak ground-state absorption that form strongly absorbing excited states can be used in optical limiters, which can protect sensors or human eyes from optical damage. Phthalocyanine complexes bearing heavy atoms or paramagnetic groups or in solvents containing heavy atoms show optical limiting enhanced by excited triplet-state absorption. A nonhomogeneous distribution of indium tetra(tert-butyl)phthalocyanine chloride along the beam path substantially enhances the excited-state absorption, yielding an optical limiter with a linear transmittance of 0.70 that can attenuate 8-nanosecond, 532-nanometer laser pulses by factors of up to 540.

Novel non-aggregated unsymmetrical metallophthalocyanines for second-order non-linear optics

Novel soluble unsymmetrical metallophthalocyanines with twelve 2,2,2-trifluoroethoxy groups as donor substituents and a mono-nitro or an exocyclic conjugated nitro group as an acceptor substituent have been synthesized and characterized. A study of the concentration dependence of UV–VIS absorption spectra showed they were non-aggregated phthalocyanines in solution and in doped polymer films. Second harmonic generation of spin-coated thin films of poly(methyl methacrylate) doped with these metallophthalocyanines was observed after electric poling at 110 °C for 30 min at a fundamental wavelength of 1.064 µm.

Syntheses and nonlinear optical properties of nonaggregated metallophthalocyanines

Hexadecakis(2,2,2-trifluoroethoxy)-substituted vanadyl and zinc phthalocyanines, and hexadecakis(ethoxy)vanadylphthalocyanine, were synthesized and characterized. Their aggregation properties were studied by evaluation of the concentration dependence of absorption spectra. Hexadecakis(2,2,2-trifluoroethoxy)-substituted metallophthalocyanines were found to be nonaggregated phthalocyanines even in the condensed state. However, nonfluorinated hexadecakis(ethoxy)vanadylphthalocyanine showed a redshift of the Q band in the solid state. The third-order nonlinear optical properties of these phthalocyanine films were studied by electroabsorption measurement in terms of molecular structure and aggregation. The aggregation effect enhances the macroscopic third-order nonlinearity of metallophthalocyanine. Among nonaggregated hexadecakis(2,2,2-trifluoroethoxy)-substituted metallophthalocyanines, zinc phthalocyanine was found to have a larger macroscopic third-order nonlinearity than the vanadyl compound.

Novel asymmetrically substituted metallophthalocyanines for nonlinear optics

Abstract Highly soluble asymmetrically substituted vanadylphthalocyanines with dodecakis(2,2,2-trifluoroethoxy) groups as a donor and a mono-nitro group as an acceptor substituent, or with extended exocyclic conjugation, have been synthesized and characterized. Their linear and nonlinear optical properties were studied. Second harmonic generation of thin films of poly(methyl methacrylate) doped with these vanadylphthalocyanines was observed after electric poling at a fundamental wavelength of 1.064 μm.

Syntheses of novel non-aggregated binuclear phthalocyaninato vanadyl complexes using a palladium- catalyzed cross-coupling reaction

Abstract Novel soluble binuclear vanadylphthalocyanines linked by terminal diacetylene bridges, such as 1,4-bis{2′-[23″-(1″,2″,3″,4″,8″,9″,10″,11″,15″,16″,17″,18″-dodecakis-(2,2,2-trifluoroethoxy)phthalocyaninyl)]ethynyl}benzene divanadyl complex, 4,4′-bis{2″-[23-(1,2,3,4,8,9,10,11,15,16,17,18-dodecakis(2,2,2-trifluoroethoxy)phthalocyaninyl)]ethynyl}- benzophenone divanadyl complex and 3,6-bis{2′-[23″-(1″,2″,3″,4″,8″,9″,10″,11″,15″,16″,17″,18″-dodecakis(2,2,2-trifluoroethoxy)phthalocyaninyl)]ethynyl}-9-tetradecylcarbazole divanadyl complex, were synthesized using a palladium-catalyzed, cross-coupling reaction between the corresponding terminal diacetylenes and an excess of 23-iodo-1,2,3,4,8,9,10,11,15,16,17,18-dodecakis(2,2,2-trifluoroethoxy)phthalocyaninato vanadyl complex. A mononuclear vanadylphthalocyanine with a conjugated carbazole moiety namely, vanadyl 23-(2′-(6″-nitro-9″-tetradecyl-3″-carbazolyl)ethynyl)-1,2,3,4,8,9,10,11,15,16,17,18-dodecakis(2,2,2-trifluoroethoxy)phthalocyaninate, was also prepared for comparison. All target phthalocyanines were separated by common column chromatography and characterized by elemental analysis, IR and 1 H-NMR, UV–visible and fast-atom-bombardment mass spectroscopies. Their UV–visible absorption spectra in solution showed that the target phthalocyanine dimers were non-aggregated compounds.

Molecular Interaction of Phthalocyanine Studied by Electroabsorption in Near IR

Abstract The linear and the nonlinear optical properties of soluble phthalocyanines in the condensed states were investigated by the absorption and the electroabsorption spectra. By a Kramers-Kronig analysis of the electroabsorption spectra, the wavelength of the maximum refractive index changes is located at around 980 nm for the casted polymer film doped with binuclear phthalocyanine.

Polarization dependence of transient absorption change in vanadylphthalocyanine

The transient absorption spectrum of a nonaggregated vanadylphthalocyanine solution has been measured by a subpicosecond pump-probe spectroscopy technique. A biexponential response with time constants of 4 ps and 800 ps has been observed. The dependence of the polarizations of pump and probe light has been investigated. The parallel-to- perpendicular ratio, i.e. the ratio of transient absorption change between configurations where pump and probe polarizations are parallel and perpendicular to each other, respectively, is 4:3. This is different from the ratio in ordinary 1D molecules, reflecting the 2D character of the vanadylphthalocyanine molecule.

Optical Characterization of Binuclear Phthalocyanines

We report the synthesis, and optical characterization of the planar binuclcar phthalocyanines metal free (-1)( H 2 Pc) 2 (t-bu) 6 and (-l)(VOPc) 2 (t-bu) 6 . Several of their optical properties, including linear absorption, concentration dependence, electroabsorption, and transient optical response were measured.