Preparation And Nonlinear Optical Properties Of Metalphthalocyanine/Graphene Composite Materials

Nonlinear optical materials present great application value in the research domains of various functionalized materials based on the light.Phthalocyanine complexes possess distinctive conjugated structure of two dimension 18 ? electrons.It could show good stability and processability by flexible tailoring molecular structure.The physical,photo electronic properties and chemical parameters of materials can be adjusted in a broad optical range.Graphene could be used as a stable and active plan for various functionalized materials due to its characteristic physical and chemical properties.In this thesis,a series of metal phthalocyanine/reduced graphene oxide composite materials were designed and synthesized.We systematically studied photophysical and third order nonlinear optical properties of metal phthalocyanine,reduced graphene oxide(RGO)and covalently functionalized composite materials of two moieties.Phthalocyanine complexes MPc(3TG)4(M=H2,Co,Ni,Cu,Zn,InCl and Pb)peripheral substituted by long chains containing C and O structure were designed and synthesized.The molecular aggregation is effective suppressed due to the modification of long chains substituent on phthalocyanine macrocycle.The photophysical and nonlinear optical properties of MPc(3TG)4 complexes are investigated by means of stable state/transient state spectra and Z-scan technique.The transient absorptive spectra of samples are localized at 550-600 nm regions and the lifetime of triplet first excited state is in 30-150?s range.The phthalocyanine complexes exhibit nonlinear reverse saturable absorption properties and its second order molecular hypersusceptibility y value is in the range of 1.37×10-32-5.66×10-33 esu.Different reduced state graphene oxide RGO-X were prepared using ethanol solvothermal method.The relationship of the sp 2 carbon configuration evolution in the graphene oxide structure with its excited state optical nonlinearity is investigated in details.By controlling the reduced temperature,one can realize controllable regulation of the number and dimension of the sp2 carbon configuration in GO structure,and further achieve the regulation of optical nonlinearity of reduced graphene oxide materials.The imaginary part 1m ?(3)value of the third order nonlinear susceptibility of the reduced sample RGO-180-24 is 7.01×10-10 esu which is 20 times as large as that of GO.Three new covalently functionalized composite materials MPc(3TG)4-RGO(M=Cu,Zn and Pb)were designed and synthesized based on an experimental program of covalent bonding and subsequent in situ reduction.We studied the electronic absorptive spectra,stable state/transient state fluorescence spectra and transient absorptive spectra of the ZnPc(3TG)4-RGO composite and analyzed the effect of electronic interaction between phthalocyanine and reduced graphene oxide on the energy level structure of composite materials in details.The nonlinear absorption coefficient ? value of the MPc(3TG)4-RGO(M=Cu,Zn and Pb)composite materials reach up 930-1400 cm/GW,which are 40-100 times as large as those of the previous corresponding metal phthalocyanine.The imaginary part Im ?(3)value of third-order nonlinear susceptibility of the composite materials is in the range of 3.27×10-10-4.91×10-10 esu.The significantly enhanced nonlinear reverse saturable absorption properties of the composite materials is closely related to the optical nonlinearity of metal phthalocyanine and reduced graphene oxide,and the synergistic effect of two moieties in the composites.The central metals of phthalocyanine complexes play a very important influence on the photophysical and nonlinear optical properties of the composite materials.