Controlling the shape of Ag nanoparticles (NPs) is very difficult. In the present work, urchin Ag NPs with different sizes and pod length control have been synthesized successfully in high yield by the concentration of a reducing agent. Unique Ag NPs were observed by TEM and SEM. These nanocrystals exhibit tunable surface plasmon resonance properties from the visible to near-infrared regions. They were applied to surface-enhanced Raman scattering (SERS) substrates using rhodamine 6G (R6G), benzenethiol (BT), and 4-amino benznethiol (4-ABT) molecules. The enhanced local field effect due to the sharp pod length, size, and surface plasmon of the urchin Ag NPs resulted in enhanced SERS properties and can serve as high-sensitivity substrates for SERS measurements.

In this study, e-beam equipment was used to form silver nanoparticles on thin films of TiO₂ to increase the efficiency of dye-sensitized solar cells and improve the annealing process. TiO₂ thin films with nanoparticle photoelectrodes were fabricated in individual units for use in dye-sensitized solar cells. The characteristics of dye-sensitized solar cells were compared to those of the prepared TiO₂ photoelectrode with and without nanoparticles. The dye-sensitized solar cells with silver nanoparticles showed a significant increase in the electric current density compared with the pure TiO₂ dye-sensitized solar cell and improved the solar conversion efficiency to 27.89%. The increased density of electric current increased the extent of light absorption of the dye owing to the plasmon resonance of the nanoparticles at the local surfaces. This phenomenon led to increased light scattering, which in turn increased the current density of the dye-sensitized solar cells and improved the solar conversion efficiency.