Self-assembled semiconductor capped metal composite nanoparticles embedded in BaTiO_3 thin films for nonlinear optical applications

摘要

A simple synthetic route with a direct self-assembling process was developed to synthesize sulfide semiconductor capped metal composite nanoparticles.Gold nanoparticles have been encapsulated with PbS nanocrystals to form spherical composite nanoparticles with core-shell structure.Stable Au@PbS composite colloids were prepared by thiourea,which acted as the linkage agent between Pb~(2+) ions and gold nanoparticles.The formation mechanism of Au@PbS composite nanoparticles was iscussed and proved with FT-IR spectra.The PbS-capped gold composite nanoparticles which served as the building blocks were successfully integrated into BaTiO_2 filoms.Significant enhancement of the femtosecond third-order nonlinear optical susceptibility in the Au@PbS_3 nanoparticles with the core-shell structure was reported.To compare effect of the enhanced nonlinear response,single gold and single PbS nanoparticles embedded in BaTiO_3 films were also prepared.