Advanced Light Trapping in Thin-film Silicon Solar Cells

Photon management is one of the key issues for improving the performance of thin-film silicon solar cells. An important part of the photon management is light trapping that helps to confine photons inside the thin absorber layers. At present light trapping is accomplished by the employment of the refractive-index matching layers at the front side and the high-reflective layers at the back contact of the solar cells and scattering of light at randomly surface-textured interfaces. In this article key issues and potential of light management in thin-film silicon solar cells are addressed. Novel approaches for light trapping are presented such as i) surface textures based on periodic diffraction gratings and modulated surface morphologies for enhanced scattering and anti-reflection, ii) metal nano-particles introducing plasmonic scattering, and iii) one-dimensional photonic-crystal-like structures for back reflectors.