Preparation Of Phthalocyanine Electrodeposited Film And Its Nonlinear Optical Properties

Phthalocyanines(Pcs)with an extensive delocalized 18-? electron system of aromatic macrocycles show excellent third order nonlinear optical properties,and have potential application in the fields of optical limiting,laser protection and optical data storage materials.Scientists have been developing materials not only with excellent third-order nonlinear optical properties but also with practical value.At present,the nonlinear optical properties of phthalocyanine solution are mainly conducted.If phthalocyanines can be applied in optical devices,thin solid films must be prepared.So,it is imperative to prepare thin film of phthalocyanines.Thin films containing unsubstituted phthalocyanines,unsubstituted naphthalocyanines and substituted phthalocyanines with n-pentyloxy,iso-pentyloxy and pyridyloxy were prepared by electrodeposition method.Effects of voltage,time and concentration on the electrodeposition of material were investigated.The electrodeposition process is followed using UV-Vis spectra,and surface morphology of the films was characterized using Atomic Force Microscope(AFM).The electrostatic self-assembly films of CoPcTs/PDDA and ZnPc(COONa)4/PDDA were prepared by electrostatic self-assembly method,and characterized using UV-Vis spectra,Polarized UV-Vis absorbance spectra,X-Ray Diffraction(XRD)and AFM.Electrodeposited thin films containing unsubstituted naphthalocyanines and substituted phthalocyanines with n-pentyloxy,iso-pentyloxy and pyridyloxy have not been reported in literature.The nonlinear optical properties of electrodeposited films and electrostatic self-assembly films containing Pcs were investigated using z-scan technique,and a series of optical parameters were obtained.Compared electrodeposited films to the pthalocyanine solutions,nonlinear absorption coefficients of electrodeposited films are 4 orders larger than that of solution sample.The molecular hyperpolarizability of the CoPcTs/PDDA film is about 50 times as large as that of the solution sample,and the nonlinear absorption coefficient of the ZnPc(COONa)4/PDDA film is 5 orders larger than that of solution sample.This indicates that the nonlinear optical properties of phthalocyanine films are much better than that of corresponding solutions.The nonlinear optical properties of phthalocyanine solution were investigated by z-scan technique,and the third-order nonlinear optical susceptibilities and the second-order molecular hyperpolarizabilities of substituted phthalocyanines with n-pentyloxy,iso-pentyloxy and pyridyloxy and unsubstituted phthalocyanines were obtained.The effect of centeral metal and peripheral substituents on the nonlinear optical properties of phthalocyanines were studied.Fluorescence lifetime,fluorescence quantum yield and triplet lifetime were acquird by fluorescence spectra and transient absorption spectra in order to study the properties of excited state and the nonlinear optical mechanism.