An efficient utilization of the sun spectrum is a key issue in the field of thin-film silicon solar cell technology. Therefore, different strategies for enhanced light absorption were presented in the last years. In order to achieve a better understanding of light scattering at nanotextured interfaces the optical properties of a large variety of samples were studied. The angle resolved scattering behavior was analyzed by means of a developed ray tracing model. As an alternative to randomly textured substrates, the influence of periodically textured substrates on the light propagation in solar cells was experimentally and numerically studied with respect to improved light in-coupling and light trapping. Based on a deeper understanding a new tandem cell structure with a diffractive element between the top and bottom cell was developed. Finally, the influence of metallic nanoparticles on the cell performance was studied.