Study On The Nonlinear Optical Properties Of The Water-soluble Phthalocyanine/graphene Composite System

Development of materials technology provides a lot of new non-linear optical material.Graphene has been proved to have excellent third-order nonlinear opticaI(NLO)properties,such as nonlinear scattering(NLS)and optical limiting(OL),and the second or third order nonlinear saturation absorption(SA),also there ultrafast carrier absorption and broadband resonance non-linear response.Although the graphene does not dissolve in most organic solvents,the advantage of graphene is that the graphene can be functionalized by organic molecules which attached to the molecules of graphenes with covalent bonding.The third order nonlinear properties ean be tuned through the attachment of different fuctional group.Former investigations have proved that phtha to cyanine(Pc)behaves the excellent non-linear optical properties.Therefore,the third order nonlinear optical properties of the graphene oxide(GO)can be improved through the method of the covalent bonding between GO and phthalocyanine.Two kinds of phthalocyanine-graphene composite system were prepared.The first kind of materials was that GO functionalized with phthakicyanine(GO-Pc)which was synthesized by amidation reaction and the other kind of materials was mixtures of graphene and sulfonic acid phthabcyanine,carboxylic acid phthatocyanine,and ether chain phthalocyanine.The graphene oxide was connected with tetra-β-carboxy-phthafocyaninato through the media of ethylene diamine.We synthesized three unreported phthalocyanine-ethylenediamine-graphene oxide covalent compounds:4-carboxy H2 phtha locyanine-ethylenediamine-graphene oxide(GO-PcH2),4-carboxy zinc phthakicyanine-ethylenediamine-graphene oxide(GO-PcZn)and 4-carboxy-copper phthalocyanine-ethylenediamine-graphene oxide(GO-PcCu).The molecule structures of above compounds were characterized using X-ray photoelectron spectroscopy(XPS),Raman spectroscopy(Raman),IR and UV-visible spectroscopy.The two kinds of compounds were studied using Z-scan technique at the wavelength of532nm,4ns pulse.The third order nonlinear susceptibilities of the same concentration were compared in the following DMSO solution,such as GO-Pc,phthafocyanine and GO solution,to investigate the third-order nonlinear optical properties.By using the laser flash photolysis methods at the wavelength of 355nm,4ns pulse.Triplet Iifetimeand time-resolved spectras of 4-carboxy zinc phthalocyanine and GO-PcZn are compared.And,the effects covalent bonding between the GO and phthafocyanine on the third order nonlinear optical properties were investigated.The results indicate that electronic transfer between the graphene oxide and Pc has a significant influence on the non-linear optical properties of graphene oxide.The third order nonlinear optical properties of two mixtures containing GO and phthalocyanine with different concentrations were studied.And,the effect of concentration of mixtures on nonlinear optical properties was also investigated.The covalent and non-covalent effects on nonlinear properties of materials under different incident laser power.was discussed.