Enhanced optical limiting properties of graphene oxide/triangular Pd nanocrystal composites

Novel graphene oxide (GO)/triangular Pd nanocrytal composites were prepared by a simple method involving the direct reduction of palladium acetate on the surface of GO. Transmission electron microscopy images confirmed that the triangular Pd nanoparticles (NPs) were successfully and homogenously deposited onto the surface of the two-dimensional GO sheet. Raman spectroscopy revealed that the loading of Pd NPs resulted in a lesser-ordered and more defective graphitic structure attributed to the increased defects and interaction between Pd NPs and GO sheets. The corresponding optical limiting (OL) behavior was investigated at 532 nm using the open aperture Z-scan technique with nanosecond pulses. Results showed that the OL property was significantly enhanced in GO/triangular Pd composites compared with its individual counterparts, indicating the usability of these hybrids in optoelectronic applications. Furthermore, the synthetic OL properties in GO/triangular Pd nanocrytal composites were found to originate from two-photon absorption in the GO sheet and nonlinear scattering in the triangular Pd NPs.