Nonlinear Optical Properties Of Phthalocyanine/graphene Oxide Solid Thin Film Materials

With the rapid development of materials science,graphene materials have shown excellent nonlinear optical properties,such as nonlinear scattering,two-photon absorption and saturated absorption,which makes them a kind of potential materials in the fields of photonic and optoelectronic,and have been applied to optical communication,optical limiting and laser alignment.The broadband nonlinear optics and optical limiting properties of graphene dispersion have been reported under the laser excitation of 532 and 1064 nm in wavelength,pulse width for nanosecond.Nevertheless,the solubility of graphene in most kinds of solvents is very poor,which is a obstacle for its use.A viable method to solve this problem is the modification of graphene oxide with some soluble materials.Graphene oxide has many oxygen-containing functional groups,such as carboxyl,hydroxyl and epoxy group,so graphene oxide can be decorated by organic or inorganic materials with covalent functionalization.Phthalocyanine and its derivatives have shown superior nonlinear optical properties,and with different substituent groups,they exhibit excellent solubility,which can modify the graphene oxide successfully.Graphene oxide covalent functionalization with tetracarboxylic Zn（II）phthalocyanine（ZnPcC₄）hybrid materials have been prepared,based on the covalent linkage of ZnPcC₄ molecules onto the graphene oxide nanosheets with or without the amino-functionalization by the ethylenediamine,and the samples have been investigated by UV-Vis,FT-IR,Raman,fluorescence,XPS and morphological analysis.We made the sol-gel materials with sol-gel method and thin film polymer materials with bulk polymerization of MMA,and measured the nonlinear optical properties of the materials with Z-scan technique.With the input intensity of 32.6μJ,the nonlinear absorption coefficientβof sol-gel materials increases from4.6*10^-11m/W for ZnPcC₄ to 7.1*10^-11m/W for ZnPcC₄-GO and 1.3*10^-10m/W for ZnPcC₄-NGO,and the value of thin-film materials increases from 5.4*10^-11m/W for ZnPcC₄ to 1.1*10^-10m/W for ZnPcC₄-GO and 1.8*10^-10m/W for ZnPcC₄-NGO.