Effects of geometry and size of noble metal nanoparticles on enhanced refractive index sensitivity

Efforts to develop and operate sensors in the early detection of diseases have led to the development of high-performance sensors. In this work, a structure of two particle (dimer) arrangements was modeled. We have changed the size of the nanoparticles and considered their separation distance is 10 nm. The coupled nanoparticles have been considered to detect refractive index changes in range of 1.32 to 1.42. The sensitivity of the proposed sensor was calculated, and the factors affecting the performance of the nanosensor such as geometry, material, sizes of nanoparticles, and refractive index of the environment are investigated. For this purpose, using the boundary element method, we have modeled various nanostructures that can excite plasmonic modes and coupling between these modes. It is found that nanoparticles with different sizes are more sensitive to refractive index changes than nanoparticles with the same sizes. The best result is obtained for nanoparticles with cubic geometry made of aluminum (Al) with a sensitivity of 600 nm/RIIU . In addition, its range of applications can be easily adjusted to a wide range of ultraviolet to visible light.