Periodically textured glass for 20% bottom cell current increase in a-Si:H/μc-Si:H tandem solar cells

OM&T | Moser Baer Technologies is investigating the approach of using periodically textured glass in combination with an optimized TCO for an improved light trapping. Diffraction next to scattering can then be used to enhance the path-length of the incoming light and this approach enables the use of relatively thin front TCO layers. Optical absorption measurements by integrating sphere were used to evaluate different textures in combination with different TCO/silicon stacks. Solar cell processing was used to verify the results. It was found that an optimized 2D grating texture in combination with a thin front TCO layer can lead to 20% higher bottom cell currents in a-Si:H/μc-Si:H tandem solar cells compared to Asahi U-type FTO.