| The two-photon absorption(TPA)materials have promising applications in the fields of two-photon fluorescence sensing,optical power limiting,photodynamic therapy and so on.Therefore,it is one of the domestic and foreign research hotspots in photoelectric field to seek the materials with strong TPA performance and study the relationship between the structures and properties of materials thoroughly.Organic/silver nanohybrids can not only combine the small size effect and surface plasmon resonance effect(SPR)of silver nanoparticles with the machinability of organic materials,but also bring new properties due to synergistic effect of the two components based on no effect to the nature of components themselves.These materials are easy to adjust and optimize the optical properties,especially enhance theTPA activity,and they have potential applications in laser protection materials and two-photon microscopy imaging in living cells.In the present study,three organic dyes with TPA activity are designed and synthesized,to couple with silver nanoparticles in the interface.So,we can obtain organic/silver nanohybrids and further study the "hot spot" group at the interface and the mechanism of the optimization of optical properties.At last,we further explore the application of materials in the fields of optical power limiting and two-photon microscopy imaging in living cells.The specific research contents are as follows:(1)Preparation,properties and application of L1-AgNPs nanohybridsAn organic functional ligand 4,4’-((4-(dimethylamino)phenyl)methylene)bis(sulfanediyl)dianiline(L1)was designed and synthesized,which coupled with 6 nm AgNPs by self-assembly method.Compared with the pure L1,the coupling interactions between L1 and AgNPs,which resulted in the changed morphology of the nanohybrids,a dramatically red-shift of single photon absorption and blue-shift of the single photon fluorescence.Especially,the TPA cross section increased by 6.7 times.The mechanisms of interaction "hot spots" at the interface and the enhancement of two-photon absorption effect were investigated by X-ray photoelectron spectroscopy and Raman spectroscopy.The enhanced TPA cross section was favorable for improving the optical power limiting performance.(2)Preparation,properties and application of L2-AgNPs nanohybridsAn organic functional ligand(E)-4-(4-(diphenylamino)benzylideneamino)benzenethiol(L2)was designed and synthesized,which coupled with 6 nm AgNPs at the interface by self-assembly method.It was found that the morphology of the nanohybrids were significantly different from those of pure AgNPs and L2,and the elemental composition and their contents of nanohybrids were analyzed by SEM-EDS.Compared with pure L2,the coupling interactions between components,which resulted in a dramatically red-shift of single photon absorption and blue-shift of the single photon fluorescence.Especially,the TPA cross section increased by 12 times.The interaction "hot spots" at the interface were investigated by Raman spectroscopy and IR spectroscopy to reveal the mechanism of the interaction.The enhanced TPA cross section was beneficial to the improvement of the optical power limiting properties of the material,which was aimed at the further application of laser protection.(3)Preparation,properties and application of L3-AgNPs nanohybridsL3-AgNPs nanohybrids were prepared from AgNPs and(E)-4-(2-(pyridin-4-yl)vinyl)aniline(L3)by in-situ.Compared with pure L3,the optical properties of nanohybrids changed significantly due to the surface plasmon resonance(SPR)effect of AgNPs:red-shifts of single photon absorption and single photon fluorescence and the increasement of fluorescence intensity and TPA cross-section.Especially,the TPA cross-section increased by 320 times than that of pure L3.The interaction "hot spots"at the interface were studied by 1HNMR and Raman spectroscopy.The increasement of TPA cross-section due to the introduction of AgNPs was beneficial to two-photon microscopy imaging in living cells. |
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