Tandem thin film solar cells composed by amorphous and microcrystalline silicon (i.e., a-Si:H/ μc-Si:H) with the top absorber (a-Si:H layer) and the intermediate layer nanopatterned as photonic crystal are studied. The optoelectronic simulations connecting the full-wave electromagnetic and the detailed electron/hole transport calculations are conducted to thoroughly evaluate the performance of the nanostructured tandem solar cells. It is found the wavelength-selective intermediate reflector between the top and bottom junction and rich interactions among multilayer Fabry-Perot, grating diffraction and other hybrid modes are responsible for the dramatic increase in the broadband absorption from the nanopatterning treatment. Moreover, the light-trapping performance of the proposed configuration is insensitive to the light polarization and can be sustained to a wide incident angle.

© 2015 Optical Society of America

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