Advanced light management approaches for thin-film silicon solar cells

Thin-film Si solar cell technology is a promising photovoltaic (PV) technology for delivering low-cost solar electricity. A drawback of this technology is a relatively low stabilized efficiency of modules that varies between 5 to 10%. Light management plays a crucial role in increasing the performance of thin-film Si solar cells. Light trapping is an important part of the light management. Application of light trapping techniques in thin-film Si solar cells increases the average optical thickness of the absorber layers resulting in an enhanced absorption especially in the long wavelength region. Several recently introduced approaches for light trapping in thin-film Si solar cells will be discussed, such as: i) periodic surface textures and modulated surface textures for efficient light scattering, ii) 1-D photonic crystals as intermediate and back reflectors for selectively enhanced reflection and suppression of parasitic optical losses at the back metal contact and iii) plasmon scattering using metal nanoparticles. Application of these novel approaches in amorphous Si solar cells will be presented. Modeling of new light trapping approaches can strongly contribute to their optimization, such as surface textures and/or size and shape of metal nanoparticles. We shall show results from optical 3-D simulations of full solar cell structures that lead to the optimization of periodic interface textures.