Reduced graphene oxide covalently functionalized with polyaniline for efficient optical nonlinearities at 532 and 1064 nm

摘要

The polyaniline (PANI) covalently grafted reduced graphene oxide (RGO) nanohybrids (RGO-PANI 1, RGO-PANI 2 and RGO-PANI 3) were fabricated by the in situ synthesis of PANI on the surface of p-phenylenediamine (PPD) functionalized graphene oxide (GO). The formation of RGO-PANI nanohybrids was confirmed by various spectroscopic techniques. The nonlinear optical performances of the as-prepared samples were investigated by the Z-scan measurements at 532 and 1064 nm with 4 ns laser pulses, the results displaying that the chemical nanohybrids (RGO-PANI 1, RGO-PANI 2 and RGO-PANI 3) exhibited enhanced optical nonlinearities compared to those of the benchmark material C-60, and the constituent RGO and PANI, due to the synergistic effects stemming from charge transfer between the two components. The role of charge transfer in the optical non linearity was clarified with the help of photocurrent and electrochemical impedance spectroscopies. By controlling the concentration of original reactants in the precursor, the PANI content in RGO-PANI nanohybrids can be precisely adjusted so that the optical nonlinearity can be tuned.