Contactless light-trapping analysis from photoluminescence

Optimising light trapping is essential for high-efficiency silicon solar cells, but conventional measurements often require completed devices. In this work, we demonstrate a contactless method that uses photoluminescence (PL) spectra to quantify optical path-length enhancement directly on silicon wafers and solar cells.

The method determines the wavelength-dependent light-trapping factor from measured PL spectra and produces results consistent with conventional quantum-efficiency measurements and optical modelling. By parameterising the spectral response, it also enables extraction of a light-trapping metric that can be compared across different wafer thicknesses and surface textures.

This makes spectral PL a powerful tool for evaluating and optimising texturing and optical design before full device fabrication, and for tracking how individual processing steps affect light trapping.