Synthesis And Nonlinear Optical Properties Of Phthalocyanine Complex

In the study of nonlinear optical materials, phthalocyanines along with their metal derivatives are macromolecules with large number of delocalized electrons and have outstanding chemical and thermal stability. The macrocyclic structure and chemical reactivity of tetrapyrroles offers architectural flexibility and capability of phthalocyanines to accommodate different metallic ions in their cavity, possessing nonlinear optical properties finding extensive applications.Traditional method of phthalocyanine synthesis at high temperature, reaction time is long, harsh reaction conditions, limiting the application of phthalocyanine. In Chapter III, we succeeded in synthesising phthalocyanines using a new intermediate of acetoxime(N,N-Diethylhydroxylamine) under a mild reaction condition. The samples were characterized by IR, UV, LC/MS and 1HNMR techniques, and the results showed that the molecular structures of the samples were consistent with our expectations. We simplified the experiment process and also improved the efficiency of the synthesis, the foundation for the application of phthalocyanines.Using the nanosecond and femtosecond laser, the nonlinear optical properties of phthalocyanines molecules are studied by the Z-scan technique. The effects of solution concentration and input laser power on nonlinear optical properties of phthalocyanines are researched. Physical mechanism of nonlinear absorption and the influence of structure of phthalocyanines on the nonlinear optical properties have been discussed. Since interaction between femtosecond laser pulse and phthalocyanines molecules, a new nonlinear optical phenomenon has been found which physical mechanism is different from that with long laser pulse, phthalocyanine solution showed strong three-photon absorption, and with the increase of concentration of its three-photon nonlinear absorption coefficient and nonlinear refractive index will increase, and when the incident power increases, its three photon absorption coefficient is essentially linear, and more confirmed the three-photon absorption is mainly caused by nonlinear absorption.The nonlinear optical properties of phenoxy-phthalocyanine-Zn (Pc2) of the best, is due to the introduction of the metal Zn, the central ion will affect the phthalocyanineπ-conjugated, charge-transfer orbit in the level energy difference, nonlinear optical properties of phthalocyanine will change. When peripheral phthalocyanine substituent introduced, whether electron withdrawing group or electron donating group than the nonlinear optical properties of substituted phthalocyanine is not excellent, because the introduction of the substituted phthalocyanine molecules, will affect the phthalocyanine system, the electron density and the degree ofπelectron conjugation, so that the phthalocyanine nonlinear optical properties of materials change.An efficient energy-level model for the phthalocyanines molecules excited by laser pulse is developed, and the intensity dependence of level populations is obtained. When nanosecond pulses input, the absorption is mainly introduced by the first excited state of Triplet state, when femtosecond pulses input, the absorption is mainly introduced by the high excited state of singlet state.