Modification of dye distribution in luminescent waveguide for higher efficiency of bifacial thin-film microscale GaAs solar cells

•The dye distribution through waveguide has been studied for the first time.•Jsc increases from 16.78 to 20.98 mA/cm2 due to the change in dye distribution.•Higher photon capturing possibility has been demonstrated in experiments.•More potential can be achieved in a given sandwich-like luminescent waveguide.

In pursuit of more wave-guided luminescence, modification of dye distribution has been proposed for the first time with surface-printed bifacial GaAs μ-cells. The short-circuit current density (Jsc) has been improved from 16.78, 17.88 to 20.98 mA/cm2 under a standard AM1.5G spectrum corresponding to uniform, 5-layered and 10-layered sandwich waveguide. More significantly, Jsc monotonically increases as the illumination aperture width (d) increases from 20 μm to 1500 μm. But only for uniform LSC, Jsc asymptotically approaches saturation value at d = 1000 μm. As a contrast, the other two cases have presented a continuous growth in Jsc even beyond d = 1500 μm, which means higher photon capturing possibility mainly due to lower optical transport losses. Compared to the uniform LSC using the same dye/matrix materials, it is convinced that sandwiched luminescent waveguide system with optimal dye concentration and optimal thicknesses of luminescent layer can promise a far better performance for surface-printed bifacial GaAs μ-cells.

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