Electrodeposition Of Ag Nanoparticles And The Applications Of Their Localized Surface Plasmons Enhancement Effect

Excitation of localized surface plasmons (LSP) by light at a frequency similar to that of the Ag nanostructure’s plasma, results in strong light scattering, absorption and enhancement of local electromagnetic fields. Hence, Ag nanostructures has great potential for applications in electromagnetic fields related areas. Surface-enhanced Raman scattering (SERS) enables ultrasensitive, low cost and real-time detection of organic molecules with extremely weak Raman signals. On the other hand, LSP of metal nanoparticles can improve the external quantum efficiency of LED and enhance the absorption of solar cell based materials. Therefore, the applications of LSP are beneficial for fabrication of highly efficient ZnO based light emitting devices and a-Si based solar cells. All these can decrease the cost of production and be beneficial for our environment.In this paper, Ag nanostructures were first electrodeposited via double-potentiostatic method. As-deposited Ag nanoparticles were utilized in SER(R)S, photoluminescence enhancement of ZnO nanorods and absorption enhancement of a-Si films. The primary achievements of this work are as follows.(1) Double-potentiostatic method was first used for electrodeposition of Ag nanostructure on ITO glass. Ag nanoparticle arrays with the lowest size standard deviation of about 3 nm and lowest distance standard deviation of about 5 nm could be achieved. Different Ag morphologies including nanoparticles, nanoflowers, hierarchical nanostructures and concave nanostructures can be obtained. The anisotropic growth of the Ag nanoparticles might be due to small nucleation driving force and electron concentration. The existence of twin defects and the small nucleation driving force might contribute to the formation of concave nanostructures. The Ag nanostructures exhibited efficient SER(R)S effect with good reproducibility.(2) It was confirmed that the local electronic field contributed to the near-band--edge luminescence enhancement of ZnO nanorods. The LSP-exciton coupling contributed to the enhancement of defect luminescence.(3) It was found that the large local electronic fields were beneficial for the light absorption of a-Si films.