Abstract. In this study, the optimization of the surface plasmon resonance (SPR) sensor based on graphene-silver substrate was investigated. We simulated the refl ection spectrum that depends on the metal thickness and the number of graphene layers. The addition of a certain number of graphene layers based on the knowledge that silver oxidation decreases the sensitivity of the sensor improved the sensitivity S RI , while the detection accuracy decreased. To optimize the sensor performance, the investigation focused on monolayer graphene. Furthermore, genetic algorithms were used to optimize the SPR biosensor refl ection by adjusting the coeffi cients of the system, which are the incidence angle and metal layer thickness.

Optical absorption in thin-film solar cells can be improved by using surface plasmons for guiding and confining the light on the nanoscale. We report theoretical and simulation studies of a-Si thin-film solar cells with silver nanocylinders on the surface. We found that surface plasmons increased the cells' spectral response over almost the entire studied solar spectrum. In the ultraviolet range and at wavelengths close to the Si band gap we observed a significant enhancement of the absorption for both thin-film and wafer-based structures. We also performed optimization studies of particle size, inter-particle distance, and dielectric environment, for obtaining maximal absorption within the substrate. A blue-shift of the resonance wavelength with increasing inter-particle distance was observed in the visible range. Cell performance improved at optimal spacing, which strongly depended on the nanoparticle size. Increasing the nanocylinder size was accompanied by the widening of the plasmon resonance band and a red-shift of the plasmon resonance peaks. A weak red-shift and plasmon peak enhancement were observed in the reflectance curve with increasing refractive index of the dielectric spacer.