The third-order optical nonlinearity of C60 and biphenyl derivatives Original Research Article

C60 biphenyl derivatives were synthesized, and their structures were characterized by FT-IR, 1H NMR and FD-MS. It was found that the products are mixture of C60(biphenyl)x and C60(biphenyl)xC60, x=3–7. The molecular images of C60(biphenyl)x and C60(biphenyl)xC60 were directly observed by scanning tunneling microscope. The Z-scan technique was used to measure the third-order optical nonlinearity of the C60 derivatives;