| Metal plasmon and semiconductor exciton have been integrated into one nanosystem through metal-semiconductor hybrid nanostructure,many new and interesting physicochemical properties were produced due to the synergistic effect between their components.In recent years,they have been widely studied in the fields of information optics,energy and environment,especially for the gold-chalcogenide nanomaterials.In this paper,metal-semiconductor nanocomposites with different symmetric structures were synthesized by using hydrothermal synthesis methods,based on gold nanorods and chalcogen semiconductors.The research and application of their surface plasmonic enhancement effects have been discussed.The details are as follows.Firstly,we synthesized the Janus-like Au-AgAuS asymmetric heterogeneous"nanoboats"structure by the selective deposition of silver atoms on the gold nanocrystals in the cetyltrimethylammonium bromide（CTAB）and cetyltrimethylammonium chloride（CTAC）dual surface modification agent systems.Their corresponding plasmon properties have been investigated through theoretical simulation and experimental methods.By use rhodamine B as the probe molecule and Au-Ag AuS is heterogeneous nanoboats as test substrate,the effect of different shell thicknesses on the performance of surface plasmon-enhanced Raman scattering was further studied.The researchs show that under the same mass of nano-gold precursors,Au-AgAuS hetero-nanoboats exhibit better Raman signal plasma enhancement than pure gold nanorods,and the thinner the semiconductor layer,the greater the enhancement factor.Those can be ascribed to the effective control of local light fields with asymmetric surface plasmon nanostructures and the efficient loading of Raman molecules on hybrid nanosturctures.Secondly,under the combined action of the Kirkendall effect and Gly-guiding cation transport,the symmetrical growth of PbSe semiconductor on gold nanorods was precisely controlled by adjusting the initial Pb2+ion concentration,obtaining Au-PbSe nano-dumbbell and yolk-shell hybrid nanorods respectively.Theoretical and experimental results show that the surface plasmon resonance properties from metal-semiconductor hybrids can be manipulated with their symmetric distribution of semiconductor shells on metal nanocrystals.In addition,based on the photoelectrochemical study of sensitized TiO2 electrodes,the photoactivities of Au-PbSe nanorods with different symmetrical structures have been investigated.The results show that the Au-PbSe yolk-shell nanorods with transverse symmetry show more excellent photocurrent response under the same mass of corresponding substances than the other samples.As a general synthesis approach,this method can also be used for the synthesis of other metal-selenide composite nanostructures（such as Au-CdSe,Au-Bi2Se3 and Au-CuSe）.In our works,we further demonstrate the bright application prospect of gold-chalcogenides nanocomposites in the fields of Raman molecular detection,photocatalystic and photoelectrocatalytic solar energy conversion. |
