Light trapping in solar cells: numerical modeling with measured surface textures

Area of Science:

• Optics and Photonics
• Materials Science
• Renewable Energy Technologies

Background:

• Accurate modeling of light propagation is crucial for optimizing thin-film solar cell performance.
• Existing models often rely on approximations for light scattering that may not reflect real-world textured surfaces.

Purpose of the Study:

• To present and validate a computational model integrating non-paraxial scalar diffraction theory and non-sequential ray-tracing for thin-film solar cells.
• To compute spectral layer absorbances directly from measured surface topographies.
• To quantify parasitic absorption without heuristic scattering distributions.

Main Methods:

• Integration of non-paraxial scalar diffraction theory with non-sequential ray-tracing.
• Direct computation of spectral layer absorbances from measured surface topographies.
• Experimental validation of the computational model.

Main Results:

• The model accurately computes spectral layer absorbances for solar cells with micro- and nano-textured interfaces.
• The commonly used Lambertian scattering approximation is shown to be violated for textured solar cells.
• Parasitic absorption is quantified directly from surface topography.

Conclusions:

• The developed model provides a more accurate representation of light propagation in textured thin-film solar cells.
• Controlling both scattering and parasitic absorption is essential for maximizing photocurrent generation.
• The findings challenge the use of simplified scattering models in solar cell design.