09:45 〜 10:00
▼ [20a-W321-4] A Universal Photochemical Approach to Ultra-Small, Well-Dispersed Nanoparticle/Reduced Graphene Oxide Hybrids with Enhanced Nonlinear Optical Properties
キーワード：femtosecond laser ablation in solution,graphene hybrids,nonlinear optical properties
Femtosecond laser ablation in solution (FLAS) is a unique and simple technique addressing the drawbacks of the conventional methods giving access to preparation of an ultra-broad spectrum of nanomaterials (NMs), since the NMs can be produced from nearly any solid materials and variable precursors in different solutions. After the energy injection in ultra-short time, extreme conditions with high temperature, high pressure and high cooling rate are created, under which various NMs can be generated. Characteristic advantages of this method are the applications in preparing a huge variety of NMs, the high purity of the products, and the in situ dispersion and functionalization of the as-prepared NMs. Here, a series of ultra-small and well-dispersed nanoparticles (NPs, e.g., ZnO, Co3O4, Ag and Ag/Co3O4 hybrid NPs) supported on the undoped and doped reduced graphene oxide (rGO) are obtained via this versatile photochemical technique, FLAS (Fig. 1a and b). Extremely fast heterogeneous nucleation rate and cooling rate having negligible thermal are proposed to play a determined role in the formation of ultra-small NPs. No surfactants, reduction reagents, or toxic materials are needed. The prepared rGO hybrids exhibit significantly enhanced ultrafast NLO response with very low optical limiting threshold (3.4 mJ/cm-2), which originates from the fast and efficient electron and/ or energy transfer from ultra-small NPs to rGO (Fig. 1c). This study may represent an important universal step toward the generation of graphene hybrid nanostructures and even complex 3D functional systems consisting of multiple functional ultra-small subunits with new horizons for numerous applications, especially in ultrafast nonlinear optics.