| Penulis/Author |
Muhammad Riswan (1); Muhammad Arifin, S.Si., M.Sc., Ph.D. (8); Dr. Iman Santoso, S.Si., M.Sc. (9); Prof. Dr.Eng. Edi Suharyadi, S.Si., M.Eng. (10) |
| Abstrak/Abstract |
The effect of an electric field on localized surface plasmon resonance (LSPR) properties of Fe3O4/Ag composite nanoparticles (NPs) was successfully investigated. Fe3O4/Ag composite NPs were synthesized by the co-precipitation method and deposited on the surface of Au thin film-coated BK7 hemispherical prisms using the spray method. A He-Ne laser beam with a wavelength of 632.8 nm was used as the light source in a Kretschmann arrays consisting of a four-layer material of a prism, Au thin film, Fe3O4/Ag composite NPs, and an air medium. A prominent resonance improvement in electro-optical activity was observed at the plasmon resonance frequency. To observe the effect of the applied electric field on the SPR angular shift, electric fields with voltage changes of 2, 4, and 6 volts were applied to prism/Au thin
film/air layer structure and prism/Au thin film/Fe3O4/Ag composite NPs/air layer structure. The SPR angle of the prism/Au thin film/air layer structures is 45,020. Under an electric field, the SPR angles shifted by 0.86°, 0.90°, and 0.94°, respectively. The LSPR angle of the prism/Au thin film/ Fe3O4/Ag composite NPs/Air structure layer is 45.46°. Under the electric field, the LSPR angles shifted by 1.36°, 1.72°, and 1.80°, respectively. The results show that the application of the electric field induces the SPR angle shift to a larger angle. Under an electric field, the LSPR angle shift (with nanoparticles) is larger than the SPR angle shift (without nanoparticles). As the electric field increases, the refractive index and the dielectric tensor of the nanoparticles change causing the shift of the LSPR angle. The significant shift in the LSPR angle due to the application of an electric field indicates that the use of an electric field could be a promising alternative to increase the performance of SPR biosensors. |
