Nonlinear Optical Properties Of Graphene/tin Based Nanocomposites

Nonlinear optics has promoted the development of laser technology, optical information technology, material analysis. Therefore, people also have a higher demand of diversity and performance of optical devices. In recent years, the enticing prospect indicated by size effect and quantum confinement effect aroused the nonlinear optical properties of the interest of the people in the nano material, and soon became the research hotspot.In this paper, the nonlinear optical properties of graphene based nano composite materials were investigated. Graphene (G)/tin oxide (G/SnO2), G/polyaniline (G/PANI) and G/tin oxide/polyaniline (G/SnO2/PANI) nanocomposites were prepared, and then they were annealed in hydrogen atmosphere. The resulting products were dispersed in N-methyl pyrrolidone (NMP) and polyvinylidene fluoride (PVDF) soulution (70%PVDF+30%NMP),respectively, to obtain the solution and the organic film. The nonlinear optical properties of samples were investigated, and the details are listed as following:1. Preparation and characterization of graphene based nanocompositesIn the experiment,G/PANI,G/SnO2 and G/SnO2/PANI nano composites with different amount of G/SnO2 were prepared, and annealed in hydrogen atmosphere. The XRD and SEM images of annealed G/SnO2 showed that SnO2/Sn core shell particles with an average diameter of about 150 um were uniformly dispersed on graphene sheets. SEM images of annealed G/SnO2/PANI with different amount of G/SnO2 showed that the diameter of SnO2/Sn core shell particles increased with the increase of the added amount; SEM images of annealed G/PANI showed that polyaniline particles were uniformly dispersed on graphene sheets.2. Investigation of nonlinear optical properties of graphene based nanocompositesGraphene based nanocomposites were dispersed in NMP solution and prepared into organic thin film, respectively. The analysis of Z-scan curves of their NMP solution showed that the annealed (G/SnO2)0.15/PANI exhibited the best performance of optical nonlinearity among samples. Therefore, the annealed (G/SnO2)0.15/PANI and other samples were prepared into organic thin film for further characterization. Z-scan curves of different input energies demonstrated the transition from saturable absorption to reverse saturable absorption,and the critical input energy is 41 μJ.