Synthesis and Optical Limiting Performance of Graphene Oxide Covalently Functionalized with Polyaniline

A soluble graphene oxide (GO) covalently functionalized with polyaniline (PANI), GO-PANI, was synthesized by an amidation reaction. The formation of an amido bond between PANI and GO was confirmed by X-ray photoelectron and Fourier Transform Infrared spectroscopy(FT-IR). By using 316 nm excitation light, both PANI and GO-PANI exhibited a strong fluorescence peak, which was located at 420 nm for PANI and 416 nm for GO-PANI, respectively. Compared with PANI, GO-PANI exhibited the 4 nm blue shift and enhanced fluorescence emission. The open aperture Z-scan results demonstrated that GO-PANI exhibited much larger nonlinear optical extinction coefficients, the imaginary third order susceptibility and better optical limiting performance than PANI at 532 nm as a result of the covalent link between GO and PANI.