Thin-film solar cells enhanced by micron and submicron spherical lenses

Thin-film solar cells enhanced by micron and submicron spherical lenses

The simple array of small transparent spheres focusing the light into the photovoltaic medium sometimes operates better than an antireflecting coating and plasmonic light-trapping structures. The simplicity and frequency stability of this light-trapping structure makes it very promising for thin-film solar cells. This work is supported by the ongoing EffiNano project of the ELEC School.

Controlling the electromagnetic fields with simple structures
(a) One of dozens of sets comprising two samples of the amorphous thin-film solar cell we have designed. The left sample (L) is covered with an optimal blooming layer. The right sample (R) is covered with our light-trapping structure. (b) This photo shows that our solar cell is flexible and semi-transparent when its circuit is open and there is no photocurrent. Red color results from the dispersion in a-Si. (c) This AFM picture illustrates the quality of our light-trapping structure. The non-covered area seen at the right of the structure is not illuminated. The best experimental result corresponds to the illumination of the most regular domain by a narrow beam. (d) For industrial adaptation the quality of the structure should be like this everywere.
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