Optical Limiting Property Of Graphene And Its Composites

Laser has brought us much convenience due to its special opticalproperties. However, the destructive capacity of laser has alreadyattracted much more attentions since its hindrance towards thesuccessfully practical utilizations. Thus the technique of optical limitinghas also been brought to the most important position in order to resist itsdestruction. The foundation of optical limiting technology is based inthe feature of the optical limiting materials, especially the ones withrapid responsive property, wide guard-band and good stability, whichhave also been brought to the research hotspots. Graphene possesseswide-band optical limiting property which has finest response towardslaser pulses at ns and ps wavebands. Thus the graphene was chosen asthe main research material in this thesis. Based on the detail studies ofthe optical limiting properties of graphene dispersion, we compositedthe graphene with several materials and intensively studied the opticallimiting properties of these composites. The detail researches are asfollows:Part I: Graphene was prepared by the method of adoptultrasonication and dispersed in a variety of organic solvents. Theoptical limiting properties of graphene with different sheet sizes havebeen investigated under different transmission rates and in varioussolvents. Subsequently, the graphenes with functionalized surfaces wasdispersed into various kinds of transparent polymer films and theiroptical limiting performances have been analyzed and compared indifferent polymeric substrates.Part II: The liquid crystal material,4-propyl-4’-butyl diphenylacetylene, was successfully synthesized and its optical limiting propertywas also investigated, which was used to modify graphene oxidation and the optical limiting performance of the composite was also been studied.As shown by the experimental results, the optical limiting property ofthe composite was dramatically improved under the irradiation of thelaser at532nm and1064nm. Especially at1064nm, the optical limitingproperty was improved significantly due to the enhanced energy transferefficiency, resulted from the increased interactions between the liquidcrystal material and the graphene.Part III: Hydroxyl pillar[5]arene was modified onto the surface ofgraphene oxide so that the dispersion of graphene oxide has beenimproved in organic solvents such as acetone. Meanwhile, the opticallimiting property of this composite was also investigated. According tothe experimental results, the optical limiting property of graphene oxidemodified with hydroxyl pillar[5]arenes has been improved under theirradiation of laser at532nm. Furthermore, other pillarene derivativesand the corresponding ligands have also been synthesized, providing thebasic materials to composite with graphene and investigate their opticallimiting properties.