Preparation And Optical Limiting Properties Of Phenyl Porphyrin And Thienyl Porphyrin Covalently Functionalized Graphene Oxide Ternary Nanohybrid Materials

Currently,graphene and its related materials have been developed in the fields of nonlinear optics(NLO)and optical limiting(OL)properties.On the one hand,the NLO properties of GO in the nanosecond(ns)and femtosecond(fs)range have been studied.On the other hand,the nonlinear optical response of a single graphene sheet dispersion has also been studied.However,graphene is poorly soluble in solvents due to the strong interactions in its structure and the presence of van der Waals forces.Non-covalent interactions and derivatization of covalent coupling can be used to improve its dispersibility and compatibility.It is more promising to form hybrid materials with strong bonding force by means of covalent bonding.In many studies,porphyrin molecules show good structural rigidity,thermal stability,photochemical and electrochemical properties.The structure of most porphyrins is the same group attached to the porphin,such as phenyl,pyridyl,and thienyl.There are few studies on heterocyclic porphyrins.Heterocyclic porphyrins can regulate their ability of donate and accept electrons.Therefore,this heterocyclic modified porphyrin can be used as a good candidate for organic-inorganic NLO materials.However,the binding direction of heterocyclic-modified porphyrins with graphene is still being explored.In particular,little research has been done on heterocyclic porphyrins and traditional tetraphenylporphyrins covalently modified graphene oxide.Chapter 2,we firstly prepared 5-p-hydroxyphenyl-10,15,20-triphenylporphyrin(TPP)and 5-p-hydroxyphenyl-10,15,20-tri(2-thienyl)porphyrin(TTP 1)by the Alder-Longo method and then covalently modified it with acid chloride graphene oxide to prepare binary and ternary organic-inorganic nanohybrid materials.Materials proved to be successfully prepared by various characterization methods and analyzed the content of each component of the material.The material's nonlinear absorption and optical limiting capabilities were tested by Z-scan technique.The ternary nano-hybrid materials exhibited better nonlinear absorption and optical limiting effects than the monomer and binary hybrid materials due to their efficient charge transfer effects.Chapter 3,5-phenyl-10,15,20-tris(p-hydroxyphenyl)porphyrin(TPP 2)and5-(2-thienyl)-10,15,20-tris(p-hydroxy Phenyl)porphyrins were covalently linked to graphene oxide by esterification reactions to prepare binary and ternary organic-inorganic nano hybrid materials.The thermodynamic stability,linear optical properties and NLO properties of GO,porphyrin and hybrid materials were studied by various spectroscopic techniques.Z-scan results show that the ternary hybrid materials exhibit enhanced nonlinear absorption optical effects.The results are attributed to the mutual synergistic effect between the monomers.Chapter 4,tetraphenylgallium porphyrin(GaClTPP)and tetra(2-thienyl)gallium porphyrin(GaClTTP)were prepared,then the binary and ternary organic-inorganic nano hybrid materials were prepared by affinity substitution reaction with hydroxyl groups on GO.A series of characterization studies were performed on the material through various spectroscopic characterizations,confirming the successful preparation of the material.The effect of electron/energy transfer in materials was investigated by steady-state fluorescence spectroscopy.The NLO performance of the material was tested using Z-scan method under a laser pulse of 523 nm and 4 ns.Z-scan results show that the ternary hybrid materials exhibit enhanced nonlinear absorption and optical limiting response.The results are attributed to the synergistic effect between the monomers and the efficient charge transfer effect.