Construction of a graphene oxide-encapsulated Pt@TiO2 core/shell ternary composite nanostructure with enhanced optical limiting behavior

A facile, simple and integrated strategy to construct a Pt@TiO2 core/shell nanoparticle-coated graphene oxide (GO) ternary composite nanostructure (Pt@TiO2/GO) as an optical limiter with high performance is reported. Pt@TiO2/GO is prepared by hydrolysis and polycondensation of titanium tetrachloride in the presence of GO to form tetragonal TiO2 NPs on GO, and then ultrafine Pt nanoparticles (NPs) are anchored on the surface of the TiO2 NPs. The nonlinear optical (NLO) and optical limiting (OL) properties of Pt@TiO2/GO are investigated using a nanosecond open-aperture Z-scan technique at 532 nm. Pt@TiO2/GO exhibits markedly improved NLO and OL performance over that of Pt/GO binary NPs and GO alone. Meanwhile, the NLO performance of the Pt@TiO2/GO ternary composites nanostructure is significantly better than that of the benchmark molecule C60 and can be further optimized by tuning the concentration of original reactants in the precursor. The possible mechanisms of this enhancement are the synergistic effect from the combination of nonlinear absorption originating from GO, nonlinear scattering induced in Pt and/or TiO2 NPs, and efficient charge transfer between TiO2 NPs and GO sheets, as well as between TiO2 and Pt NPs.