Preparation And Properties Of Lanthanide Phthalocyanine-graphene Optical Limiting Materials

Laser technology has been widely used in civil and military applications such as laser surgery,industrial processing,communications,optical imaging and attack weapons.High-intensity laser beams can pose potential hazards to human eyes and optical devices,and people are increasingly concerned about avoiding damage caused by accidental laser radiation.Therefore,optical power limitation?OPL?technology has made tremendous progress under huge demands.For OPL materials,high transmittance can be maintained at lower light intensities,and the transmittance gradually decreases as the light intensity increases.The development of powerful optical limiters remains a huge challenge,as excellent optically constrained materials are still limited.To date,in order to develop highly efficient optical limiters,different mechanisms have been applied to reduce laser intensity,such as absorption,reflection and diffraction.Among them,nonlinear optical?NLO?materials with strong nonlinear absorption or scattering response are ideal materials for different laser pulse optical limiters.However,NLO materials designed by a single strategy still do not meet the actual needs of the application.Multi-mechanism combination and synergistic enhancement effects are considered to be effective methods for designing efficient NLO materials.The graphene oxide dispersion exhibits broadband NLO and OL characteristics when excited at nanometer pulses at 532 nm and 1064 nm,but the nonlinear extinction coefficients at these two wavelengths are not high enough to meet the practical needs of optical limiting.Moreover,the dispersion stability of graphene in an organic solvent is also poor,and it is easy to aggregate or settle.These have become obstacles to their application.One of the possible ways to solve these problems is to chemically modify GO with some soluble materials,and covalently modify different organic molecules to obtain functionalized graphene.This modified graphene not only has more in organic solvents.Good dispersion stability and a significantly improved nonlinear extinction coefficient.In this thesis,several GO hybrid materials were prepared by modifying GO with lanthanide phthalocyanine.The photophysical properties,microstructure and molecular structure and properties of GO nano hybrid materials were discussed from the design ideas of different nonlinear optical mechanisms.The relationship has been studied as follows:1)Using GO phthalocyanine modified GO to prepare two kinds of axial bond and GO hybrid materials,both materials have better dispersibility than original GO in DMF,two materials combined with phthalocyanine,rare earth elements,GO Advantages in various aspects,such as large nonlinear optical coefficient and fast photoelectric response of phthalocyanine,OPL response of GO at 1064nm,and rare earth elements can promote the inter-system to triplet nature,becoming a new type of broadband optical limiting material.Significant fluorescence quenching indicates electron transfer between the two combinations,which also enables photoelectron/energy transfer?PET/ET?processes with two hybrid materials at 532and 1064 nm under the same pulsed laser energy illumination.The optical confinement ability is improved,especially the?_eff value at 1064 nm reaches 0.331cm GW-1,which is 23 times higher than that before modification.2)In order to further improve the dispersibility of GO hybrid materials in organic solvents,and the nonlinear extinction coefficient at 532 and 1064 nm,inspired by various excellent properties of hyperbranched metal phthalocyanine?HMePc?oligomers,the same chemical bonds Two kinds of hyperbranched lanthanide phthalocyanine modified GO hybrid materials were synthesized.The two hybrid materials combined with the good properties of HMePc showed more stable dispersion than MePc-GO hybrids.Also,dispersed in DMF at the same concentration of 0.1 mg mL-1,HBMePc-GO showed a larger nonlinear extinction coefficient value than the single molecule modified hybrid MePc-GO due to the special structure of hyperbranched phthalocyanine.This allows the HBMePc-GO hybrid to have more efficient electron/energy transfer while exhibiting stronger fluorescence quenching than MePc-GO.In summary,two kinds of new optical confinement materials have been prepared by surface modification of GO.By comparing the structure and properties of the two materials,it provides a theoretical basis for the regulation of nonlinear optical materials.Based on this,the nonlinear optical material is regulated.